Antibiotics doi: 10.3390/antibiotics15111099

Authors: Verena Zerbato Stefano Di Bella Chiara Ercolini Nicholas Geremia Markus Zeitlinger Matthias Jackwerth Luigi Principe

The global spread of multidrug-resistant Gram-negative bacteria has increased the need for β-lactamase inhibitors with broader activity. This narrative review examines nacubactam and xeruborbactam, two emerging inhibitors with distinct pharmacological and microbiological profiles. Nacubactam combines serine β-lactamase inhibition with PBP2 binding and β-lactam-enhancing activity, whereas xeruborbactam provides broader enzymatic coverage, including several clinically relevant metallo-β-lactamases and OXA carbapenemases. Their clinical development is also at different stages, with phase III efficacy data already available for nacubactam-based combinations, while xeruborbactam remains supported mainly by preclinical and phase I evidence. Rather than being interchangeable, nacubactam and xeruborbactam may therefore occupy distinct and potentially complementary roles in the future treatment of multidrug-resistant Gram-negative infections.

Antibiotics doi: 10.3390/antibiotics15111098

Authors: Olivia Mobarakai Wendy Stead Jeffrey Larnard

Orthopedic implant infections—including prosthetic joint infections (PJI), fracture-related infections (FRI), and spinal implant infections (SII)—represent a spectrum of biofilm-associated infections that are associated with substantial morbidity, prolonged antimicrobial therapy, and frequent need for surgical intervention. Rifampin is often incorporated into antimicrobial treatment regimens for orthopedic implant infections due to its potent biofilm-penetrating properties and has been most studied in the treatment of staphylococcal PJIs, though the majority of data is observational. Its use is frequently complicated by adverse effects and significant drug–drug interactions, and the role of rifampin beyond staphylococcal PJIs managed with implant retention or one-stage exchange remains controversial. In this review, we critically evaluate the evidence for use of rifampin in PJI, with additional consideration of its role in FRIs, SIIs, and PJIs caused by staphylococcal and other Gram-positive organisms. Using illustrative cases, we provide a practical framework for navigating common clinical scenarios and challenges involving the use of rifampin in orthopedic implant infections.

Antibiotics doi: 10.3390/antibiotics15111097

Authors: Danuta Łoboda Robert D. Wojtyczka Krzysztof S. Gołba Michał Joniec Dorota Łyko-Morawska Anna Schikora Sylwia Gładysz-Wańha Julia Staroń Denis Swolana Michał Gibiński Beata Sarecka-Hujar

Background: Cardiac implantable electronic device (CIED) infections require transvenous lead extraction, followed by 2–6 weeks of antimicrobial treatment. Case presentation: This series describes CIED infection cases treated with the long-acting lipoglycopeptide antibiotic oritavancin, based on preliminary data from the ORI-4-CIEDi study (ClinicalTrials.gov ID: NCT07013552). Eleven patients (2 women), with a median age of 67.0 years (range 28.0–78.0), received oritavancin administered as a single dose or as multiple doses at 7-day intervals. The etiological factors included: (1) methicillin-sensitive (MS) or methicillin-resistant (MR) coagulase-negative staphylococci (CoNS) in three cases; (2) MS Staphylococcus aureus and MS-CoNS; (3) MR-CoNS and vancomycin-resistant (VRE) Enterococcus faecium; (4) vancomycin-intermediate S. aureus and VRE E. faecium; (5) MR-CoNS, Corynebacterium spp., Peanibacillus humicus, and Acinetobacter baumannii; and (6) Gram-positive rod Bacillus cereus. In two cases, oritavancin therapy was continued empirically. In one case, only Gram-negative bacillus Pseudomonas stutzeri was cultured, leading to discontinuation of oritavancin. Nine participants (81.8%) underwent transvenous lead extraction (TLE), one (9.1%) received pocket debridement and relocation, and one (9.1%) was managed conservatively. Definitive treatment success, defined as a clinical response without recurrence of infection during the 3-month follow-up, was achieved in five participants (62.5%) with infections involving Gram-positive cocci and in two participants (100.0%) with infection of unknown etiology, including one managed conservatively. In two cases infected with Gram-positive cocci, follow-up after TLE was discontinued prematurely due to death from cardiogenic shock, and only complete healing of the surgical wound was observed. In the patient who had undergone non-radical surgery, long-term suppressive therapy against CoNS proved ineffective. Discussion: Weekly administration of long-acting oritavancin in CIED infections with Gram-positive cocci has the potential to enhance patient comfort and support outpatient parenteral antimicrobial therapy. Conclusions: These preliminary findings are encouraging; however, outcomes should be interpreted within the context of the overall treatment strategy, including source-control procedures and combined antimicrobial therapy, rather than attributing results solely to oritavancin.

Antibiotics doi: 10.3390/antibiotics15111096

Authors: Ahmed G. K. Habib Nada A. Fahmy Bibek Lamichhane Yosra A. Helmy

Escherichia coli Nissle 1917 (EcN) is one of the most intensively investigated Gram-negative probiotic strains that have been clinically used for over a century. However, how EcN’s strain-specific traits contribute to its probiotic activity, safety profile, and therapeutic potential remains poorly understood. In this review, we link its clinical history and unique microbiological and genomic characteristics to the bioactive molecules and cell-surface structures responsible for its probiotic activity. These include antimicrobial microcins and siderophore-microcins, iron-acquisition systems, and locally acting metabolites involved in nutrient competition and colonization. They also include outer membrane vesicles and surface structures, such as lipopolysaccharide, flagella, fimbriae, and capsular polysaccharides, that mediate host interactions, barrier protection, and immune modulation. Together, these factors support intestinal homeostasis and distinguish EcN from pathogenic E. coli. By controlling pathogens through non-antibiotic mechanisms, EcN may also support antibiotic-sparing approaches that can help prevent antimicrobial resistance. However, many molecular functions are supported primarily by in vitro and animal studies, and their contribution to clinical efficacy remains less well established. We also discuss safety considerations, particularly the pks/colibactin island, genotoxicity, and long-term therapeutic use. By linking EcN’s clinical relevance to its molecular traits, we highlight how mechanistic understanding can support next-generation probiotics and live biotherapeutic products.

Antibiotics doi: 10.3390/antibiotics15111095

Authors: Sena Nur Başaran Lütfiye Öksüz İmdat Kılbaş İhsan Hakkı Çiftçi

Background: Antimicrobial resistance (AMR) is a major global health threat, with bacterial efflux pumps representing an important mechanism that reduces antibiotic efficacy by actively expelling antimicrobial agents from bacterial cells. Efflux pump inhibitors (EPIs) have therefore emerged as promising antibiotic adjuvants. Methods: This study presents a bibliometric analysis of EPI research published between 1991 and 2025 using the Web of Science Core Collection. Of 1078 identified publications, 835 original research articles were included. Publication trends, citation patterns, country and author contributions, scientific disciplines, thematic clusters, and keyword co-occurrence patterns were analyzed using VOSviewer version 1.6.21. Results: Publication output showed an overall upward trend over the study period, with higher annual publication counts in the later years. The United States led in publications (156), citations (9122), and collaborations (80), followed by India (103) and China (94). Lomovskaya et al. (2001) was the most cited article (752 citations). Microbiology was the leading research category (329; 39.4%), followed by Pharmacology & Pharmacy (269; 32.2%). Phytochemicals represented 7.3% of meso-level citation topics. Conclusions: EPI research has expanded over the study period, encompassing a multidisciplinary range of topics primarily related to antimicrobial resistance mechanisms, bacterial efflux systems, and inhibitor discovery. These findings underscore the need to strengthen the connection between fundamental research and translational applications, particularly through the systematic evaluation of EPI efficacy, safety, and therapeutic potential.

Antibiotics doi: 10.3390/antibiotics15111094

Authors: Jakub Piotr Aleksiejuk Jan Kiryluk Marta Eliza Plonska-Brzezinska

Implant-associated biofilms are a major barrier to successful treatment of periprosthetic joint infection (PJI) because surface-adherent microbial communities embedded in extracellular polymeric substance exhibit marked tolerance to antimicrobial therapy and host defenses. Electrical and electrochemical approaches offer a mechanistically distinct strategy for directly disrupting these communities at conductive implant surfaces. This review critically evaluates mechanistic, in vitro, animal, translational, and early clinical evidence for electrical and electrochemical control of implant-associated biofilms, with particular emphasis on orthopedic applications. Low-intensity direct current, cathodic voltage-controlled electrical stimulation, electrolytic cleaning, alternating and pulsed fields, and radiofrequency approaches can promote biofilm detachment, bacterial killing, or antimicrobial sensitization through polarity- and dose-dependent effects involving local pH shifts, electrolysis, reactive species generation, gas evolution, matrix disruption, and altered transport across the biofilm. Experimental studies consistently demonstrate antibiofilm activity on metallic implant surfaces, and animal models provide additional support, particularly for combinations with antibiotics. However, interpretation is constrained by heterogeneous electrical dosing, simplified implant geometries, young or single-species biofilms, variable endpoints, and limited assessment of corrosion and tissue safety. Human evidence remains largely limited to dental peri-implantitis, and no completed clinical trial has established efficacy in hip or knee PJI. Electrical and electrochemical decontamination should therefore be considered promising but investigational adjuncts to surgical source control and antimicrobial therapy in orthopedic periimplantitis. Translation will require standardized dose reporting, clinically realistic biofilm and implant models, rigorous electrochemical and tissue safety assessment, and controlled trials evaluating infection-free implant retention and patient benefit.

Antibiotics doi: 10.3390/antibiotics15111093

Authors: Maryam Jawad Fatima Wasif Dar Fatmaelzahraa Gamil Omar Zaina Asif Hussain Marfoha Tabassum Osama Ahmed Amal A. H. Gadalla

Background: Urinary tract infections (UTIs) are a major global health burden that drives substantial antimicrobial use. Microbiological culture, the reference standard, can miss uropathogens and delay appropriate treatment, promoting interest in genomic approaches. Here, we systematically review the diagnostic accuracy of genomic methods and discuss their positivity criteria, turnaround time (TAT) and clinical impact. Methods: The Scopus and PubMed databases were searched for studies published between January 2020 and January 2026 that evaluated genomic methods for UTI diagnosis against microbiological culture and reported accuracy. Sensitivity and specificity were pooled separately using binomial-normal generalised linear mixed models (GLMM). Quality assessment was conducted using QUADAS-2. TAT and clinical impact were synthesised narratively. The review protocol was registered with PROSPERO (CRD420261294559). Results: Thirteen studies were included. Genomic methods showed high pooled sensitivity with moderate heterogeneity (0.94; 95% CI 0.87–0.98, τ2 = 1.43). However, pooled specificity was moderate and highly variable (0.61; 95% CI 0.23–0.89; τ2 = 5.92). The criteria used to define a positive genomic result varied widely, the shortest TAT was 4–6 h, and evidence on clinical outcomes was limited to two studies. Conclusions: Genomic methods are sensitive, potentially rapid, detect organisms missed by culture and characterise microbial diversity. However, their moderate, variable specificity likely reflects both limitations of culture as a reference standard and inconsistent genomic positivity criteria. As culture-negative, genomic-positive results may have explanations other than infection, they should be interpreted alongside symptoms and pre-test probability. Standardised positivity criteria and evidence of clinical benefit are needed before routine implementation.

Antibiotics doi: 10.3390/antibiotics15111092

Authors: Luke C. Hicks Matthew J. Urban Hailey Y. Maurer Steven J. DiSpirito Maggie Cortes Sarah E. Montanti Eleanor P.-B. Race Sophia Cozza Kaveesha N. Kulkarni Benjamin R. Carone Valerie J. Carabetta Jeffrey D. Hettinger Gregory A. Caputo

Background: Antimicrobial resistance has developed as a significant world health problem, and numerous approaches have been actively studied to address the challenge. Some metals, including silver, copper, and zinc, have emerged as potential alternatives to traditional antibiotics, especially in the context of medical devices and coatings that can be applied to these devices. However, the effective dose and spectrum of activity of these metals have been areas of question for many material scientists, as well as those looking to translate the coatings into clinical trials. Methods: Here, we have evaluated the efficacy of three antimicrobial metals in solution against a panel of clinically relevant bacteria grown in three different growth media types. We used a combination of microbiological approaches, including determining susceptibility by broth microdilution assays, bacterial growth curves, analysis of biofilm mass using crystal violet binding and metabolism using XTT conversion, and analysis of bacterial morphology by scanning electron microscopy. Results: The results demonstrate that not all antimicrobial metals are equally effective in all media types. Across all conditions tested, Ag+ ions were the most effective, followed by Cu2+ and Zn2+. Notably, Cu2+ and Zn2+ showed increased variability in MIC against bacteria grown in nutrient broth media, with both increased susceptibility and decreased growth rates for all bacteria tested. Both E. coli and S. aureus exhibited significantly smaller cell sizes in NB media when treated with metal ions. Bacterial biofilms grown in nutrient broth media exhibited lower metabolic activity and decreased biomass, although not statistically significant in all cases. Importantly, when compared to mammalian cytotoxicity levels, the dramatic effects of media on the MIC values can have significant impact on calculations of effective dosage. Conclusions: These results demonstrate that studies on the antimicrobial efficacy of metal-based antimicrobials, including metal-based coatings, should be viewed through the lens of differential activity depending on the media conditions used.

Antibiotics doi: 10.3390/antibiotics15111091

Authors: Sabita D. Stoeckle Anais Sauerwein Elisabeth Mueller Heidrun Gehlen

Background: Multidrug-resistant organisms increasingly challenge infection prevention and control (IPC) in equine referral hospitals. Objectives: Assessment of selected environmental indicator pathogens in an equine teaching hospital and evaluation of their relevance for nosocomial wound infections. Study design: Observational study with repeated environmental sampling and retrospective evaluation of wound culture submissions. Methods: During three sampling periods (SPs), surface samples were collected across functional areas before and after routine cleaning/disinfection. Revision of the cleaning/disinfection protocols and environmental support staff feedback and training was performed between SP 1 and 2. Indicator pathogens were defined as an equine-adapted ESKAPEE-derived panel. Samples from surgical wounds were considered nosocomial if infection developed ≥3 days after hospitalisation. Results: Indicator pathogens were detected in all SPs, with the greatest frequency and diversity in SP 1. SP 1 yielded indicator pathogens in 25.7% of the 152 samples. After IPC optimisation, detection decreased in SP 2 to 11.2% of the 152 samples. In SP 3 with fewer samples (n = 42) sporadic recovery (7.1%) was observed. Contamination involved in particular high-touch surfaces and floors, and several pathogens persisted after cleaning/disinfection. Of 125 wounds, 38 met the criteria for nosocomial infection. Isolated from both, the environment and infected wounds were Streptococcus equi ssp. zooepidemicus, Staphylococcus aureus, Escherichia coli, and Enterobacter cloacae. Molecular typing was unavailable. Conclusions: Environmental equine-relevant indicator pathogens were detected across clinical areas. Some persisted after routine cleaning and/or were detected in nosocomial wound infections. Revision of cleaning/disinfection protocols with staff training was temporarily associated with reduced environmental contamination.

Antibiotics doi: 10.3390/antibiotics15111089

Authors: Georgi Lukanov Alexander Slavov Vensan Velchov

This review traces 5 decades of systemic antibiotic therapy for periprosthetic joint infection (PJI) and classifies each element of current regimens by the evidence behind it. In the 1970s, one-stage exchange with antibiotic-loaded cement was developed in Hamburg, initially without systemic antibiotics. North American two-stage exchange adopted the 6 weeks of intravenous therapy used for osteomyelitis. The first randomised trial of an antibiotic combination (1998) reported cure in 12 of 12 patients given rifampicin–ciprofloxacin and 7 of 12 given ciprofloxacin alone (24 of 33 randomised patients analysed; wide confidence interval). We identified 14 randomised trials of systemic therapy that enrolled patients with PJI and assessed their risk of bias; 10 randomised trials enrolled fewer than 200 patients. Of the three with more than 400 patients, OVIVA (2019) found early oral therapy non-inferior to intravenous therapy in bone and joint infection; DATIPO (2021) did not show 6 weeks to be non-inferior to 12, with the largest difference after debridement and implant retention; and SOLARIO (2026) found 7 days or less of systemic therapy non-inferior to 4 weeks or more when a local antibiotic carrier was implanted. A trial of oral therapy after reimplantation reported less reinfection, with 15% of patients lost to follow-up. The 3- and 6-month durations recommended since 2004 have been compared with a shorter course in one trial of 63 patients. Certainty of evidence was moderate for early oral therapy and low or very low for most questions of duration and agent; several components of current practice remain untested.

Antibiotics doi: 10.3390/antibiotics15111090

Authors: Rezak Drali Jessica Arliaud Margaux Mercadal Amira Doudou Julie Martinez Dimitri Gonzalez Laurent Deblir Ronan Boulmé Chalom Sayada Sofiane Mohamed

Background/Objectives: Routine diagnostic microbiology relies on separate workflows for pathogen identification, resistance genotyping, and molecular surveillance. This proof-of-concept study evaluated the feasibility of consolidating targeted assays for bacterial pathogens and DNA and RNA viruses within a single DNBSEQ-E25 sequencing run coupled with automated bioinformatic interpretation. Methods: Twenty-five libraries generated from 21 unique external quality assessment materials, reference strains, and anonymized residual clinical specimens were analysed. Targeted assays covered Mycobacterium tuberculosis resistance-associated regions, human immunodeficiency virus type 1 (HIV-1), cytomegalovirus (CMV), full-length bacterial 16S rRNA, and influenza A/B. Outcomes included on-target sequencing yield, coverage, and pathogen-specific resistance and typing results. Results: The 25 libraries generated 39,962,528 reads, with 82.6% mapping to the intended targets. Both tuberculosis materials yielded resistance profiles concordant with the expected results. HIV-1 pol libraries achieved complete target coverage, whereas whole-genome coverage reached 89.4–91.1%. Both cytomegalovirus formats achieved complete target coverage except for UL54 in the multiplex format, reflecting substantial UL54 depth imbalance. Bacterial 16S results were consistent with the reference organisms, and influenza sequencing enabled subtype and clade assignment. Conclusions: These findings support the technical feasibility of consolidating the evaluated targeted assays within a single DNBSEQ-E25 run. The limited sample set and absence of replicate runs preclude conclusions regarding reproducibility or clinical performance.

Antibiotics doi: 10.3390/antibiotics15111088

Authors: Haiyi Li Jinghui Ma Qiongfang Zhu Siying Qu Jie Xu

β-lactam antibiotics are fundamental to antimicrobial treatment. They inhibit bacterial cell-wall synthesis, and are particularly important for treating Gram-positive bacterial infections. Bacteria have evolved several mechanisms of β-lactam resistance, among which alterations in penicillin-binding proteins (PBPs) are particularly important in the Gram-positive pathogens discussed here. This review summarizes PBP functions and PBP-mediated resistance mechanisms in Staphylococcus aureus, Enterococci, and Streptococcus pneumoniae, aiming to inform drug development and guide new therapeutic strategies against resistance.

Antibiotics doi: 10.3390/antibiotics15111087

Authors: Laura Isabell Werneburg Ramona Schweyen Karl-Stefan Delank Felix Werneburg

Background/Objectives: The oral cavity is a potential Staphylococcus aureus reservoir, but whether oral strains are genetically related to S. aureus at other body sites of the same individual is unclear. This scoping review mapped the evidence on within-person genotypic concordance between oral and extraoral S. aureus and on the direction of dissemination. Methods: Following PRISMA-ScR, PubMed and Web of Science were searched (last update 28 September 2026), supplemented by citation and recent-literature searches, for human studies comparing S. aureus from a true oral specimen with isolates from at least one extraoral site of the same individual by a strain-level genotypic method (e.g., pulsed-field gel electrophoresis, multilocus sequence typing, whole-genome sequencing). Findings were synthesized descriptively. Results: Fifteen reports (2003–2026) were included, covering 16 oral–extraoral comparisons: oral–nasal (n = 7), oral–lower respiratory or endotracheal (n = 5), oral–skin/wound (n = 3), and oral–rectal (n = 1). Within-person concordance was frequent but not universal: in the largest paired oral–nasal whole-genome study, 23 of 34 dual-site carriers (67.6%) harbored the same clone, and among intubated patients, 13 of 22 oral–nasal and 16 of 26 oral–subglottic isolate pairs differed by ≤9 single-nucleotide polymorphisms. Directional evidence was sparse and bidirectional, ranging from an oral clone preceding tracheal colonization to patterns compatible with nasal-to-oral seeding. Conclusions: Genetically related S. aureus lineages are repeatedly shared between the oral cavity and extraoral sites, supporting the oral cavity as one component of a dynamic multisite reservoir that is not addressed by screening and decolonization strategies directed at the nares alone. Establishing whether it is an upstream source of extraoral colonization or infection requires longitudinal multisite studies with high-resolution genomics.

Antibiotics doi: 10.3390/antibiotics15111086

Authors: Dan-Alexandru Toc Alex-Gabriel Beilic Andreea Cristina Fratila Ovidiu Stefan Ionita Ana-Flavia Dulău Paul Cristian Martian Alexandru Botan Ioana Alina Colosi Carmen Costache

Enterococcus faecium is a major healthcare-associated pathogen whose increasing resistance to clinically important antimicrobials has created a need for faster susceptibility-testing approaches. This narrative review critically evaluated the available evidence on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) biomarkers for predicting antimicrobial resistance in E. faecium. PubMed/MEDLINE, Scopus, and Web of Science Core Collection were searched from database inception to 15 July 2026, without language or publication-date restrictions. Seventeen studies met the eligibility criteria. Most investigated vancomycin resistance or the presence of vanA and vanB, whereas fewer addressed ampicillin resistance, resistance to other antimicrobials, or lineage discrimination. Several individual peaks and machine-learning models showed high discriminatory performance within their respective study populations. However, direct comparisons were limited by substantial heterogeneity in isolate collections, culture conditions, sample-preparation protocols, MALDI-TOF MS platforms, spectral-processing pipelines, feature-selection methods, and validation strategies. Most reported biomarkers lacked molecular annotation, and some previously proposed signals could not be reproduced in independent collections, suggesting that certain peaks may reflect clonal lineage rather than a direct resistance mechanism. External and multicenter validation also remained limited. MALDI-TOF MS-based resistance prediction therefore represents a promising rapid screening or decision-support approach but cannot currently replace reference phenotypic antimicrobial susceptibility testing. Future research should prioritize standardized experimental and analytical workflows, isolate-level data partitioning, geographically diverse multicenter cohorts, independent external validation, and integrated proteomic and genomic characterization of candidate biomarkers.

Antibiotics doi: 10.3390/antibiotics15111085

Authors: Micaela Shinya-Hidalgo José Rodrigo W. Martínez Sophie Squella Patricia García Manuel Alcalde-Rico José Manuel Munita Aniela Wozniak

Background/Objectives: This study investigated the emergence of cefiderocol (FDC) non-susceptibility among clinical isolates of ceftazidime–avibactam-resistant Pseudomonas aeruginosa in Chile, a setting where FDC has not yet been introduced into clinical practice. Methods: Seventy-seven ceftazidime–avibactam-resistant isolates were analyzed through antimicrobial susceptibility testing, efflux pump inhibition assays, and whole-genome sequencing. Results: Of the 77 isolates, 21 carried blaVIM, 33 carried blaPER, and 23 did not carry any extended-spectrum β-lactamase nor carbapenemases (NP isolates). Among FDC-non-susceptible isolates, seven of them were intermediate (MIC = 8 μg/mL) and eight were resistant (MIC ≥ 16 μg/mL). PER was significantly more prevalent in non-susceptible than susceptible isolates (p = 0.010). MIC90 were markedly higher for NP and PER isolates, being 32 μg/mL and 16 μg/mL, respectively, compared to 0.5 μg/mL for VIM isolates. Phenotypic analyses demonstrated that inhibition of efflux pumps significantly reduced FDC MIC, particularly among non-susceptible isolates, indicating that active efflux contributes to FDC resistance. Whole-genome sequencing revealed predominance of the high-risk clone ST309 among PER-producing isolates. Comparative genomic analyses showed that FDC non-susceptibility was associated with the cumulative burden of mutations affecting iron-uptake pathways, AmpC/PBPs, and efflux pumps/permeability. Accessory genome analysis identified an ISPa38-like element carrying mercury-resistance genes that was significantly more common among FDC-susceptible isolates. Conclusions: FDC non-susceptibility in P. aeruginosa is a complex phenotype driven by the interaction of acquired β-lactam resistance determinants, chromosomal adaptations, and active efflux mechanisms. The detection of this phenotype in an FDC-naïve setting suggests that resistance may emerge indirectly through collateral selection, raising concerns about the future effectiveness of FDC against high-risk multidrug-resistant lineages like PER-producing ST309.

Antibiotics doi: 10.3390/antibiotics15111084

Authors: Ilias Karaiskos Georgia Vrioni Antonio Vena Daniele Roberto Giacobbe Patricia Muñoz

Antimicrobial susceptibility testing (AST) is evolving from conventional culture-based methods toward rapid phenotypic, molecular, sequencing, and artificial intelligence-assisted approaches. This narrative review examines current and emerging strategies for Gram-negative bacteria and proposes a conceptual round-trip framework for integrating genotype, phenotype, and clinical outcome evaluation. Phenotypic AST remains the functional reference because it measures growth inhibition under standardized conditions and provides drug-specific minimum inhibitory concentrations or categorical results. Rapid phenotypic platforms can shorten time to actionable susceptibility information, whereas multiplex molecular panels provide earlier pathogen identification and detection of selected resistance mechanisms. Whole-genome, metagenomic, and long-read sequencing extend this information to resistance architecture, plasmid context, transmission, and surveillance, while validated machine-learning approaches may support drug-specific susceptibility prediction. However, genotype–phenotype discordance, incomplete resistance-gene coverage, workflow constraints, and limited evidence for consistent improvement in patient outcomes remain important limitations. The proposed model links early molecular information with phenotypic testing, discordance review, expert clinical interpretation, and governed investigational learning. Reference phenotypic AST supplies susceptibility labels; clinical outcomes are evaluated separately. External validation and prospective assessment are required before the proposed learning extension can support clinical care.

Antibiotics doi: 10.3390/antibiotics15111083

Authors: Berfin Çirkin Doruk Mustafa Uğuz

Background: Systemic antifungal treatment in intensive care units (ICUs) is frequently initiated before microbiological confirmation. Earthquake-affected ICUs provide an important setting for examining antifungal decision-making under sudden patient surges and disrupted care processes. We compared initiation patterns across ordinary pre-pandemic, COVID-19, and earthquake-affected ICU cohorts. Methods: This retrospective single-center study included 566 adults receiving systemic antifungal therapy for suspected or blood-culture-confirmed Candida bloodstream infection: 256 ordinary pre-pandemic, 150 COVID-19, and 160 earthquake-affected patients. Initiation was classified as empirical, culture-guided, or same-day indeterminate using the recorded ICU days of treatment initiation and blood culture positivity. Initial antifungal class, documented infectious diseases consultation, and total treatment duration were compared. Thirty-day all-cause mortality after antifungal initiation was a secondary exploratory outcome. Results: Initiation patterns differed across cohorts (p < 0.001; Cramer’s V = 0.449). Empirical initiation occurred in 15.6%, 85.3%, and 69.4% of ordinary, COVID-19, and earthquake-affected patients, respectively. Echinocandins accounted for 96.0% of initial therapy in the COVID-19 cohort. Infectious diseases consultation was documented in 80.5%, 66.7%, and 19.4%, respectively. Median treatment durations were 8 (interquartile range, 6–10), 8 (4–14), and 6 (5–7) days (p < 0.001). After excluding 63 same-day cases, empirical initiation was not significantly associated with mortality after adjustment (adjusted odds ratio, 0.891; 95% confidence interval, 0.522–1.519; p = 0.671). Alternative same-day classifications also yielded nonsignificant associations. Conclusions: Recorded antifungal initiation timing and treatment patterns differed across the three ICU cohorts. These descriptive findings do not establish causal effects of healthcare context, treatment appropriateness, or equivalence between initiation approaches.

Antibiotics doi: 10.3390/antibiotics15111082

Authors: Justine Fri Angelina Maphula Tjale Cloupas Mahopo Idris Njanje Amidou Samie Lufuno Grace Mavhandu-Ramarumo Pascal Obong Bessong

Background: The inappropriate use of antibiotics contributes to the development and spread of antibiotic resistance. Community education plays an important role in mitigating this threat; however, community-derived data required to inform the co-creation of solutions and development of awareness packages remain limited. This study assessed knowledge, attitudes, and practices (KAP) regarding antibiotic use in a community participating in a longitudinal enteric antibiotic resistance research project to inform targeted community interventions. Methods: This cross-sectional study included 917 residents of nine villages in a rural community in Limpopo Province, South Africa. Data on antibiotic use and resistance were collected using a structured questionnaire comprising closed-ended items and two open-ended questions. The four-point Likert-scale responses were scored based on appropriateness, with possible scores ranging from 0 to 14 for knowledge, 0 to 7 for attitudes and 0 to 5 for practice. Quantitative data were analysed using descriptive statistics, bivariate and multivariable logistic regression, while qualitative responses were analysed thematically. Results: The median age of participants was 34 years (IQR: 22), and the majority were females (61.5%), unemployed (67.0%), single (69.1%) and had less than Grade 12 education (60.0%). The mean percentage KAP scores were 67.9 ± 9.3%, 27.3 ± 22.5%, and 61.9 ± 11.0%, respectively. Most participants had moderate knowledge (82.9%), negative attitudes (83.8%) and suboptimal practices (83.2%). Major knowledge misconceptions concerned the effectiveness of antibiotics against viruses and most coughs and colds. More than 70% expressed inappropriate attitudes towards obtaining antibiotics without a prescription or from relatives or friends, keeping antibiotics for future use, and stopping treatment when they felt better. Notable inappropriate practices included obtaining antibiotics based on the experiences of family or friends (77.8%) and stopping the medication when symptoms disappear (94.7%). Unemployed participants had higher odds of having at least moderate knowledge compared to the employed (aOR = 1.48, 95% CI: 1.02–2.14), those aged ≥50 years had lower odds of a positive attitude than those aged 16–24 years (aOR = 0.35, 95% CI: 0.19–0.68), and participants with less than Grade 12 education had lower odds of good practice than those with Grade 12 education (aOR = 0.62, 95% CI: 0.42–0.91). Positive attitudes were associated with higher odds of good antibiotic-use practice than negative attitudes (aOR = 2.21, 95% CI: 1.46–3.34). Qualitative findings supported the quantitative results by revealing perceptions of antibiotic effectiveness alongside persistent misconceptions, including beliefs that antibiotics treat viral infections or should be used frequently. Conclusions: Although participants demonstrated moderate overall knowledge, important misconceptions coexisted with predominantly negative attitudes and poor reported practices. These findings identify priority areas for subsequent responsive dialogues with stakeholders to co-create locally appropriate community antimicrobial stewardship interventions.

Antibiotics doi: 10.3390/antibiotics15111081

Authors: Li Huang Xiaoqing Fu Yuhao Wang Xinmiao Wu Bo Pang Zhenpeng Li Xin Lu Shiwen Zhao Biao Kan

Background: The misuse of antibiotics in aquaculture and clinical settings promotes drug resistance in food-related microbes. Vibrio parahaemolyticus, a global pathogen linked to diarrheal disease and food safety concerns, warrants a systematic assessment of its resistance. Methods: We analyzed 9757 high-quality V. parahaemolyticus genomes retrieved from NCBI (1950–2023). ARGs, mobile genetic elements (MGEs), plasmid replicons, sequence types, and virulence genes were identified. Associations between ARGs and genomic/macro-level factors were assessed, and strain-level resistance risk was evaluated using arg_ranker. Results: Among all sequenced strains, 99.59% were pathogenic, and 23.57% were food and aquatic animal sources. Furthermore, pan-resistome analysis indicated that ARGs carried by the V. parahaemolyticus population are expanding. Notably, most ARG types were enriched in strains from food and aquatic animals. In terms of temporal trends, shifts in resistance categories highlight tetracyclines, penams, and phosphonic acid antibiotics as priority surveillance targets, given that their associated ARGs have recently increased. Consistent with these findings, a positive correlation was found between ARG abundance and mobile genetic element (MGE) count per strain, specifically with tnpA as the most frequently co-occurring MGE. In addition, dynamic changes in predominant plasmid replicon types were documented, among which IncA/C2 and Col3M show co-occurrence with high-risk ARGs. Finally, risk assessment classified 95.18% of strains as Risk Level IV (lowest). Conclusions: Although the overall global resistance risk remains low, strains from food and aquatic animals contained the highest proportion of higher-risk (Rank I and II) strains among all sources. This study provides updated insights into antimicrobial resistance trends in V. parahaemolyticus and offers a theoretical foundation for guiding future resistance management strategies.

Antibiotics doi: 10.3390/antibiotics15111080

Authors: Maria-Elena Vodarici Roxana-Carmen Cernat Elena Dumea Oana-Elena Ioniţă Nicola-Maria Vișan Petronela-Anca Dumitrescu Rareș-Alexandru Constantin Andreea Mara Cambrea Gabriela Mitea Florin Gabriel Pănculescu Valeriu Gheorghiţă Irina-Magdalena Dumitru

Extensively drug-resistant (XDR) and pandrug-resistant (PDR) Gram-negative bacteria—principally carbapenem-resistant Acinetobacter baumannii (CRAB), carbapenem-resistant Enterobacterales (CRE), and difficult-to-treat resistant (DTR) Pseudomonas aeruginosa—account for a growing share of severe nosocomial infections and rank among the pathogens of greatest public health concern. In the 2024 World Health Organization Bacterial Priority Pathogens List, CRAB and carbapenem-resistant Enterobacterales are classified as critical-priority pathogens and carbapenem-resistant P. aeruginosa as a high-priority pathogen, whereas difficult-to-treat resistance is a clinical resistance definition and not a WHO priority category. Because monotherapy is frequently inadequate or unavailable, combination regimens remain central to bedside decision-making, and antimicrobial synergy testing has moved from a niche laboratory exercise to a question with direct clinical relevance. This narrative review synthesises recent literature identified through a structured search, the preparation of which was guided by the SANRA quality criteria for narrative review articles. The synthesis is organised across four linked domains. First, the molecular mechanisms that determine which of the following combinations are rational: carbapenemase production, efflux- and porin-mediated impermeability, lipid A modification and polymyxin resistance, and iron-transport alterations underlying emerging cefiderocol resistance. Second, the laboratory methods used to detect synergy—the checkerboard assay and fractional inhibitory concentration index, time-kill assays, and dynamic pharmacokinetic/pharmacodynamic models, including the hollow-fibre infection model—and the genotype-dependence that limits their generalisability. Third, two agents whose combination behaviour is atypical: (1) cefiderocol, whose iron-transport-dependent uptake makes its synergy testing uniquely medium-dependent and for which pooled observational data in CRAB have reported lower mortality with monotherapy than with cefiderocol-containing combination regimens, although confounding by indication limits causal interpretation and (2) intravenous fosfomycin, whose unique MurA target and the risk of rapid resistance emergence during monotherapy often favour its use in combination regimens for severe MDR/XDR infections. Fourth, the clinical evidence from the ATTACK randomised trial of sulbactam-durlobactam in CRAB to large multicentre cohorts of ceftazidime-avibactam plus aztreonam in metallo-β-lactamase-producing Enterobacterales. We conclude that in vitro synergy testing retains clear value for individualising therapy when no single active agent can be identified, but that its translation to the bedside requires genotype-aware interpretation, pharmacokinetic or pharmacodynamic context, and corroboration against comparative clinical data rather than extrapolation from checkerboard results alone.

Antibiotics doi: 10.3390/antibiotics15111079

Authors: Brunella Posteraro Flavio De Maio Giordana Cafaro Ada Teti Tiziana D’Inzeo Barbara Fiori Giulia Menchinelli Maurizio Sanguinetti

Background/Objectives: Ceftazidime–avibactam (CZA) resistance in KPC-producing Klebsiella pneumoniae is frequently associated with variant KPC enzymes, but the resulting susceptibility to other β-lactam/β-lactamase inhibitor combinations remains difficult to predict. We investigated the genomic characteristics and collateral susceptibility profiles of CZA-resistant KPC-producing K. pneumoniae colonizing isolates. Methods: This retrospective study included a selected collection of 38 isolates recovered from rectal screening samples between 2019 and 2023, with only one isolate per patient included. Isolates underwent whole-genome sequencing and susceptibility testing to aztreonam–avibactam (AZT–AVI), meropenem–vaborbactam (MEM–VAB), imipenem–relebactam (IMI–REL), and meropenem. MICs were interpreted according to EUCAST 2026 criteria. Results: Twelve blaKPC alleles were identified. The most frequent were blaKPC-31 (17/38, 44.7%) and blaKPC-66 (7/38, 18.4%), while the remaining 14 isolates carried ten less frequent alleles. Most KPC variants involved the Ω-loop. OmpK35 and OmpK36 alterations were common and frequently occurred together. AZT–AVI was active against all isolates, whereas susceptibility to MEM–VAB, IMI–REL, and meropenem was 89.5%, 81.6%, and 44.7%, respectively. Marked MIC variability was observed among isolates carrying the same blaKPC allele, including isolates with identical OmpK35 and OmpK36 profiles. Resistance to MEM–VAB and IMI–REL showed incomplete overlap across allelic backgrounds. Conclusions: Within this collection, isolates carrying the same blaKPC allele and porin profile could exhibit different collateral susceptibility patterns, supporting direct susceptibility testing of individual β-lactam/β-lactamase inhibitor combinations.

Antibiotics doi: 10.3390/antibiotics15111078

Authors: Supanut Prasertsin Suwalak Chitcharoen Pratsanee Hiengrach Parama Budmala Waewta Kuwatjanakul Supranee Phanthanawiboon Vorthon Sawaswong Auttawit Sirichoat

Background/Objectives: The Stenotrophomonas maltophilia complex (Smc) comprises opportunistic bacteria with substantial antimicrobial resistance and genomic diversity. This study investigated the antimicrobial susceptibility and genomic characteristics of clinical Smc isolates from a university hospital in Thailand. Methods: Fifty clinical isolates underwent broth microdilution susceptibility testing and whole-genome sequencing. Analyses included average nucleotide identity, digital DNA–DNA hybridization, multilocus sequence typing, screening for resistance- and virulence-associated genes, prediction of mobile genetic elements, and SNP-based phylogenetic analysis. Results: Forty-nine isolates were assigned to eight species, and the remaining isolate, which could not be resolved at the species level, was designated Stenotrophomonas sp. The predominant groups were S. maltophilia and S. sepilia (n = 14 each), followed by S. hibiscicola (n = 12). Resistance to trimethoprim–sulfamethoxazole and levofloxacin was detected in 14% and 16% of isolates, respectively. Thirty-six isolates (72%) were not assigned to an existing sequence type by seven-locus MLST. Phylogenetic analysis resolved eight major clades corresponding to the reported species. Resistance-associated annotations included aminoglycoside-modifying enzymes, β-lactamases, and efflux-associated proteins. Predicted mobile genetic elements varied among isolates. Conclusions: These findings describe genomic diversity and antimicrobial susceptibility in a single-hospital collection of clinical Smc isolates from Thailand. They provide a foundation for genomic surveillance and the investigation of resistance-associated features. Broader sampling and functional validation are needed to establish the clinical significance of the predicted genomic features.

Antibiotics doi: 10.3390/antibiotics15111077

Authors: Vincenzo Pennone Stefania Mamberti Giada Meogrossi Monica Abbondi Barbara Canciani Camilla Recordati David Sarlah Fabio Sangalli Elena De Vecchi Emanuela Galliera Arianna Barbara Lovati

Background: Orthopedic implant-associated infections are difficult to eradicate because of biofilm formation and impaired healing. FK-16 and GF-17 are short synthetic antimicrobial fragments of the human cathelicidin LL-37; FK-16 consists of 16 amino acids and differs from the 17-amino-acid GF-17 by the absence of its N-terminal glycine. This study aimed to assess their acute tolerability following single-dose intravenous administration in mice and to evaluate the local antibacterial efficacy of FK-16 delivered via peptide-enriched silk fibroin (PSF) scaffolds in a rat model of methicillin-resistant Staphylococcus epidermidis (MRSE)-associated femoral nonunion. Methods: Thirty-six BALB/c mice (18 males and 18 females) received vehicle, FK-16, or GF-17 (0.1 or 1 mg/kg for each peptide) and underwent clinical and functional assessments, hemolysis testing, biochemical analyses, organ-weight measurements, and histopathological examination. Thirty-two male Wistar rats were assigned to a noninfected control group or infected groups treated with unloaded PSF, vancomycin-loaded PSF, or FK-16-loaded PSF. On day 56, antibacterial activity and bone healing were evaluated using microbiological culture, micro-computed tomography, and histopathology. Results: No mortality, persistent neurobehavioral abnormalities, or treatment-related organ lesions occurred in mice. Transient hind-limb paralysis occurred in one mouse treated with FK-16 and one treated with GF-17 at 1 mg/kg. Biochemical and hemolysis-related changes were isolated and did not follow a consistent dose–response pattern; no corresponding treatment-related organ lesions were observed. In rats, viable MRSE was recovered from 3/4 untreated specimens and none from those treated with vancomycin or FK-16. FK-16 was associated with partial normalization of the circulating ratio of osteoprotegerin to receptor activator of nuclear factor-κB ligand without significantly reducing early systemic inflammation. Bone mineral density, tissue mineral density, and bone volume fraction increased numerically, but no quantitative micro-computed tomography healing parameter improved significantly; the radiographic osteomyelitis score decreased significantly. Untreated PSF showed absent bridging, abundant fibrovascular tissue, chronic inflammation, rare Gram-positive cocci, and higher histological scores than noninfected controls; both treated groups showed minimal inflammation but incomplete bridging. Conclusions: FK-16 and GF-17 showed generally acceptable acute tolerability despite transient high-dose neurological effects. Locally delivered FK-16 demonstrated antibacterial activity, reduced osteomyelitis severity, and was associated with minimal histological evidence of inflammation, but did not significantly improve quantitative bone healing or restore complete bridging by day 56.

Antibiotics doi: 10.3390/antibiotics15111076

Authors: László Gombos Imre Nemes László Búza Enikő Varga Eszter Kollár-Nagy Zoltán Somogyi Veronika Szűr László Varga

Background/Objectives: Farm-level monitoring of antimicrobial use (AMU) is essential for mitigating antimicrobial resistance (AMR) within a One Health framework because aggregated sales data cannot identify farms and production stages with high AMU. This study evaluated year-to-year changes in AMU intensity and antimicrobial-class distribution in a longitudinal cohort of 492 large-scale Hungarian pig farms in 2023 and 2024 and identified priorities for antimicrobial stewardship. Methods: Mandatory veterinarian-reported AMU data were analyzed retrospectively. The same 492 farms were included in both years, representing approximately 3.7 million pigs in 2023 and 3.8 million in 2024. AMU intensity was expressed as milligrams of active substance per kilogram of pig biomass using the standard live weights specified in the European Medicines Agency’s ESUAvet methodology: 120 kg per slaughter pig and 240 kg per breeding sow. Antimicrobials were grouped by Antimicrobial Advice Ad Hoc Expert Group (AMEG) category. Results: In the 492-farm cohort, AMU intensity was 5.1% lower in 2024 than in 2023 (55.0 versus 57.9 mg/kg biomass). Category B intensity decreased in all farm categories; Category C increased on only-fattener and breeding farms but decreased on farrow-to-finish farms; Category D remained dominant. AMU was concentrated in specific production stages and farms: 57.5–86.4% of breeding-unit AMU was reported for post-weaning pigs, the 20 farms with the highest absolute use accounted for 43.3% of total cohort AMU, and the 20 farms with the highest absolute Category B use accounted for approximately 68.8% of cohort Category B use. Oral formulations represented 93% of reported antimicrobial quantity. Medicated-premix use decreased by approximately 25%, while drinking-water and injectable formulations increased. Conclusions: Mandatory farm-level surveillance provides data for benchmarking and targeted stewardship. Interventions should distinguish absolute use from biomass-adjusted intensity and focus on farms with disproportionate use and the post-weaning phase. The observed 2023–2024 difference is descriptive; additional years of data are needed to assess longer-term patterns in AMU intensity.

Antibiotics doi: 10.3390/antibiotics15111075

Authors: Tsepo Ramatla Jane Nkhebenyane Tshegofatso Motlhaoloa Khasapane G. Ntelekwane

Introduction: Poultry production can serve as an important reservoir of antimicrobial-resistant bacteria. Although surveillance commonly focuses on prevalent organisms such as Clostridium perfringens, less prevalent anaerobic spore-forming bacteria may also contribute to the antimicrobial resistance reservoir. This study characterised Paraclostridium bifermentans recovered from broiler chicken faeces and compared its antimicrobial resistance profiles with those of co-resident C. perfringens. Methods: Ninety-six pooled avian faecal samples were screened for P. bifermentans. Isolates were identified using biochemical testing and 16S rRNA gene sequencing. Antimicrobial susceptibility was assessed against five antibiotic classes, and selected antimicrobial resistance genes (ARGs) were detected using conventional PCR. Phenotypic resistance profiles were compared with those of 52 previously characterised C. perfringens isolates recovered from the same sampling population. Results: Six P. bifermentans isolates were recovered from 96 pooled samples (6.25%) and showed 99.9% 16S rRNA gene sequence similarity to reference P. bifermentans sequences. All six isolates were multi-drug-resistant, compared with 24/52 (46.15%) C. perfringens isolates (Fisher’s exact test, p = 0.024). P. bifermentans showed significantly higher resistance to chloramphenicol (100% vs. 34.62%, p = 0.003) and clindamycin (100% vs. 46.15%, p = 0.024) than C. perfringens. Resistance genes were variably detected among the P. bifermentans isolates. All six isolates carried tet(A), while tet(W) was detected in 33.3%. The blaOXA gene was detected at 66.7%, and catIV and catII were detected in 66.7% and 33.3%, respectively. Phenotypic resistance was not consistently explained by the ARGs targeted in this study. Conclusions: The recovery of multi-drug-resistant P. bifermentans from broiler faeces indicates that this less frequently recovered organism may represent an under-recognised component of the antimicrobial resistance reservoir in the investigated poultry environment. However, the small number of isolates limits generalisation. Further studies using larger sample sizes and whole-genome or functional approaches are required to determine the diversity, genomic context, expression, and potential mobility of resistance determinants in P. bifermentans.

Antibiotics doi: 10.3390/antibiotics15111074

Authors: Emre Yücel Dionysios Ntais Mike Allen David W. Hilbert Mary R. Motyl Fakhar Siddiqui Katherine Young Hannah Collings Medi Stone

Background: Multidrug-resistant (MDR) Pseudomonas aeruginosa infections are associated with substantial morbidity, mortality and therapeutic uncertainty, particularly in critically ill and immunocompromised patients. Imipenem/cilastatin/relebactam (IMI/REL) combines the established carbapenem imipenem with cilastatin, a dehydropeptidase-I inhibitor, and relebactam, a diazabicyclooctane beta-lactamase inhibitor that restores imipenem activity against selected class A and class C beta-lactamase-mediated resistance mechanisms. Methods: A targeted narrative review was undertaken to identify and provide an overview of published observational studies and conference abstracts reporting clinical outcomes with IMI/REL in patients with confirmed or suspected MDR P. aeruginosa infection. Evidence was summarized descriptively, because the available studies were heterogeneous in design, infection site, patient severity, pathogen mix, susceptibility testing and outcome definitions. Results: Real-world IMI/REL data remain limited but are increasingly informative. IMI/REL was commonly used in high-risk patients, including those with pneumonia, bacteremia, intensive care admission, prior antimicrobial exposure, polymicrobial infection or limited alternative treatment options. Reported clinical success or clinical cure was observed in approximately 56–70.2% of patients, although interpretation is limited by non-comparative designs, small patient populations and mixed-pathogen populations. Thirty-day all-cause mortality varied widely, broadly reflecting baseline severity, infection site and salvage-therapy use. Emergence of IMI/REL non-susceptibility was variably reported, but some recent studies report high rates of treatment-emergent resistance; this requires caution and remains an important area for surveillance. Conclusions: IMI/REL appears to be a clinically useful option for susceptible MDR P. aeruginosa infections, particularly in patients with limited alternatives. Available real-world evidence should be interpreted cautiously, because most data derive from retrospective uncontrolled cohorts.

Antibiotics doi: 10.3390/antibiotics15111073

Authors: Sumarheni Sumarheni Shagun Gogna Minh Phuong Theresa Nguyen Giovanni Battista Migliori H. Manisha Yapa Jin-Gun Cho Jan-Willem Alffenaar

Background/Objectives: Coinfection with tuberculosis (TB) and respiratory viral infections (RVIs) complicates clinical management due to polypharmacy, potential drug–drug interactions (DDIs), and adverse drug reactions (ADRs). We aimed to evaluate patient-level treatment data, focusing on potential DDIs, reported or suspected ADRs, clinical outcomes, and opportunities for pharmacist involvement in the management of TB/RVI coinfection. Methods: This systematic review was registered in PROSPERO CRD420251125786 and conducted following PRISMA guidelines. We searched MEDLINE, PubMed, Embase, Web of Science, and Scopus for case reports and case series of TB/RVI coinfection. Study quality was assessed using the Joanna Briggs Institute (JBI) tools. Potential DDIs between TB medicines and concomitant medicines were assessed using three drug interaction checkers and synthesized descriptively. Results: A total of 186 patients described in 108 studies were included. The studies reported 79 single-patient and 29 two- or more patient-level data on treatment. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was the most frequently reported RVI (89.8%). An ADR was reported in 16 of 186 published cases (8.6%), mainly related to hepatotoxicity (11/21 ADR events; 52.4%), followed by anemia/cytopenia and gastrointestinal intolerance. Four contraindicated and 50 serious potential DDIs requiring close monitoring were identified, mostly involving rifampicin. Because the evidence consists of published case reports and case series, these proportions are descriptive rather than population risk estimates. Conclusions: TB/RVI coinfection is characterized by substantial polypharmacy, potential DDIs, and risk of ADRs. None of the included reports described pharmacist involvement. These findings suggest that pharmacist involvement in multidisciplinary TB services, together with co-treatment guidance, warrants evaluation to improve medication safety.

Antibiotics doi: 10.3390/antibiotics15111072

Authors: Angel Montero Lage Alexandre Lamas Freire Emiliano J. Quinto Carlos M. Franco Beatriz I. Vázquez

Background/Objectives: Brassica spp. constitute an important group of edible plants. Over the last century, the important power of these plants as bioactive producers with anticancer, anti-inflammatory, antioxidant or cardioprotective properties has clearly been established. There are many species of this genus, with more than 34 species, as well as several subspecies. Brassica species also have antimicrobial properties, and this is an important aspect of this group. Therefore, the objective of this study was to explore the antimicrobial properties of extracts of different Brassica species. These aspects are important to consider in actual antimicrobial resistance crises and in terms of the possible modulation of the gut microbiota by these foods. Methods: A search of the scientific literature was carried out using the Scopus, Web of Science and Google Scholar databases. The search was carried out regarding antimicrobials as well as Brassica as the main initial term. From the great number of papers found, those with minimum inhibitory concentration (MIC) data and aspects such as the extraction procedure, as well as the proven microorganisms, were selected. Results: A total of 41 papers were selected from the literature. Most of them were from Brassica oleracea, with a total of 14 papers. There are differences between different species, as well as among the different parts of the plants, depending on the extraction procedure used to obtain the extracts. Conclusions: Higher antimicrobial power was detected for the extracts of Brassica rapa, whose best value was 0.25 µg/mL, when hydrodistillation or microwave hydrodistillation was used. Additionally, Brassica nigra (black mustard) showed the greatest inhibition when it was extracted in the vapor phase, with the best value of 0.012 µg/mL. No reviews regarding the MICs of Brassica extracts have been carried out until now.

Antibiotics doi: 10.3390/antibiotics15111071

Authors: Francesco Carrozzo Alessandro Milia Serena Scacchi Alberto Antonelli Marco Coppi Roberto Spampatti Tommaso Pelagatti Angelamaria Becorpi Filippo Pieralli Gian Maria Rossolini

Background/Objectives: Essential oils (EOs) are volatile, biologically active compounds naturally extracted from aromatic plants. Known for their broad-spectrum antimicrobial properties, EOs are gaining increasing attention as potential alternative or complementary agents in clinical practice, especially in the face of rising antibiotic resistance. EOs act through multiple mechanisms, including disruption of microbial membranes, interference with enzyme activity, and inhibition of quorum sensing pathways, making them promising antimicrobial candidates against multidrug-resistant organisms (MDROs). Methods: In this study, the in vitro antimicrobial activity of seven essential oil batches, including Eucalyptus globulus, Lavandula hybrida, Melaleuca alternifolia, Pelargonium graveolens, Coriandrum sativum, Cymbopogon winterianus, and Cinnamomum zeylanicum, was evaluated against five reference strains and ten clinical strains mostly belonging to ESKAPE species, plus Stenotrophomonas maltophilia, Achromobacter xylosoxidans, and Burkholderia cepacia complex. Results: The tested EO batches displayed heterogeneous antimicrobial activity: Cinnamomum zeylanicum exhibited the strongest and broadest antibacterial effect, showing consistently low minimum inhibitory concentration (MIC) values across all tested strains, including carbapenemase-producing and non-fermenting Gram-negative bacteria. The remaining oils showed moderate-to-limited activity, particularly against Gram-negative strains. The two Klebsiella pneumoniae strains producing either KPC or NDM carbapenemases, and the Pseudomonas aeruginosa PAO-1 strain, showed the highest MIC values for all EOs, except for C. zeylanicum, for which MICs were 0.125 and 0.25% (v/v), respectively. Conclusions: The consistently low MIC values of the C. zeylanicum batch against the panel of tested strains suggested a potential for this essential oil and for its bioactive constituents as promising candidates against several MDROs.

Antibiotics doi: 10.3390/antibiotics15111070

Authors: Burcu Karagülle Zeynep Yerlikaya Yasin Öztürk İbrahim Canpolat Selçuk Başer Daniele Marini Chiara Storoni Vincenzo Cuteri Anna-Rita Attili

Background/Objectives: Feline otitis externa is less well characterized microbiologically than the canine disease. This retrospective laboratory-based study described cultivable otic microorganisms and antimicrobial resistance among isolates from 112 animals with otitis externa (46 dogs and 66 cats). Methods: A total of 204 archived isolates were identified to species level by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Bacterial isolates underwent disk-diffusion antimicrobial susceptibility testing with organism-specific panels. Record-based multiple antibiotic resistance (MAR) indices and an organism-specific exploratory multidrug resistance (MDR) category assessment were calculated. Phenotypically methicillin-resistant staphylococci were tested for mecA by PCR. Results: The collection comprised 188 bacterial and 16 yeast isolates. Staphylococcus pseudintermedius was the most frequent (30/204; 14.7%), followed by Staphylococcus aureus (21/204; 10.3%), Escherichia coli (20/204; 9.8%), Pseudomonas aeruginosa (17/204; 8.3%), and Proteus mirabilis (15/204; 7.4%). Of 181 bacterial isolates with AST records, 171 had at least one MAR-eligible result; mean record-based MAR indices were 0.341 in canine isolates (n = 88) and 0.343 in feline isolates (n = 83). Heterogeneous panels and incomplete interpretative provenance precluded a standardized pooled MDR estimate. mecA was detected in 19/28 (67.9%) phenotypically methicillin-resistant staphylococci, including 8/12 (66.7%) S. pseudintermedius and 11/15 (73.3%) S. aureus isolates. Conclusions: This study documented diverse cultivable otic microorganisms, species-dependent antimicrobial resistance profiles, and mecA-positive staphylococci among archived isolates from dogs and cats with otitis externa. These findings contribute to the characterization of antimicrobial resistance in companion-animal otic isolates, while requiring cautious interpretation in relation to topical treatment.

Antibiotics doi: 10.3390/antibiotics15111069

Authors: Montserrat Rodríguez-Gómez Francisco Braojos Sánchez Carolina Parra Esteban Stalina Frometa Carrillo María Soledad Arellano Serrano Marina López-Olivencia Carmen de Burgos-Lunar Cruz Soriano-Cuesta Francisco Javier Candel Fernando Martínez Sagasti

Background/Objectives: Stenotrophomonas maltophilia is a common cause of lower respiratory tract infection (LRTI) in critically ill patients, but differences between ventilator-associated tracheobronchitis (VAT) and ventilator- or hospital-acquired pneumonia (VAP/HAP) remain unclear. We aimed to compare clinical outcomes between VAT and VAP/HAP and, secondarily, to explore antimicrobial treatment patterns and their association with treatment failure. Methods: We conducted a retrospective two-center cohort study of adults admitted to intensive care units (ICUs) in Madrid, Spain, between August 2021 and December 2025 with clinically significant S. maltophilia VAT, VAP, or HAP. The primary analysis included only the first (index) episode per patient. Results: Sixty-seven patients contributed 90 episodes. Among index episodes, therapeutic failure was more frequent in VAP/HAP than in VAT (40.6% vs. 14.3%; absolute risk difference, 26.3 percentage points; 95% confidence interval [CI], 5.0–45.2; p = 0.026). In a parsimonious Firth’s penalized logistic regression, VAP/HAP remained associated with therapeutic failure (adjusted odds ratio, 4.06; 95% CI, 1.32–14.25; p = 0.014). Results were consistent after adjustment for SOFA score at infection onset and when the analysis was restricted to VAP. ICU mortality was numerically higher in VAP/HAP (46.9% vs. 25.7%). In an exploratory Firth’s model, laboratory-reported in vitro active antimicrobial therapy was associated with lower odds of failure (adjusted odds ratio, 0.19; 95% CI, 0.05–0.72; p = 0.014); however, this exposure was susceptible to time-dependent bias, and empirical anti-S. maltophilia therapy, defined at treatment initiation, was not associated with failure (26.7% vs. 26.9%). Conclusions: The clinical and prognostic significance of respiratory S. maltophilia infection appears to differ by syndrome. VAP/HAP was associated with more therapeutic failure than VAT. The association between in vitro active therapy and lower failure was exploratory and requires confirmation, and no comparative effectiveness conclusions can be drawn for individual antimicrobial agents.

Antibiotics doi: 10.3390/antibiotics15111068

Authors: Hüseyin Kutlu Cemil Çolak Mehmet Cengiz Çolak

Background/Objectives: Machine learning applied to MALDI-TOF mass spectra can flag antimicrobial resistance days before conventional susceptibility testing, but models rarely retain accuracy in a new laboratory. We asked whether this failure can be repaired without target-site labels and, if a few local labels are obtainable, how they should be chosen. Methods: We assembled 72 cross-site species–antibiotic transfer tasks from DRIAMS (eight species, 18 agents, three site pairs) in 12 prespecified clusters. After benchmarking unsupervised adaptation, five label-free shift descriptors were used to choose between Random and Hybrid acquisition at 20, 30 and 50 target labels, under nested leave-one-cluster-out validation with cluster-level sign-flip inference. Results: Source–target separability was uniformly high (domain AUROC: 0.966–1.000), while external PR-AUC varied widely (0.049–0.920), and no unsupervised method restored transportability. The selective policy numerically exceeded Always-Random at all budgets (+0.0084, +0.0078 and +0.0048 PR-AUC; p = 0.064, 0.012 and 0.045). The 30-label result was robust to excluding development tasks, duplicated phenotypes and post hoc descriptor choice, but not to accounting for isolates shared between clusters (p = 0.06–0.09), and the policy did not outperform Always-Hybrid. Conclusions: Site identity persists in MALDI-TOF spectra despite harmonization, so cross-site deployment is better planned around a small local labeling budget than around label-free correction. Shift-informed acquisition is a methodological proof of concept: its gains were small and statistically fragile, it did not outperform Always-Hybrid, and independent laboratory validation and local recalibration are required before any clinical application.

Antibiotics doi: 10.3390/antibiotics15111067

Authors: Nuha Almulla Hanaa Bahaa Elkhouly Raya Soltane Omar Khaled Lamia Ryad Mohamed Khedr Omiya A. Hasan Eman Maher Zahran

Background/Objectives: Targeting bacterial virulence mechanisms and associated inflammation represents a compelling strategy to disarm pathogens without imposing selective survival pressure. While Euphorbia tirucalli (Pencil Cactus) synthesizes potent bioactive secondary metabolites, the extreme irritancy of its raw phytocomplex has historically hindered its biomedical application. This study aimed to overcome these limitations via polymeric nanoencapsulation, leveraging the metabolome of E. tirucalli stem extract to attenuate bacterial virulence and cellular inflammation. Methods: Chemical profiling was conducted via high-resolution LC-Q-Orbitrap HRMS. Polymeric nanoparticles were fabricated using different stabilizers (Tween 80, ethyl cellulose, and PEG 6000) and characterized using TEM, DLS, and XRD. In vitro release kinetics were analyzed in PBS (pH 7.4). Biological evaluations encompassed agar well diffusion, broth microdilution (MIC/MBC), qRT-PCR transcriptional analysis of virulence/biofilm genes in standard bacterial strains (Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli), and anti-inflammatory profiling in LPS-stimulated RAW 264.7 murine macrophages via ELISA. Results: HRMS tentatively annotated 46 metabolites, predominantly methoxy flavonoids, flavonoid glycosides, and phenolic acids. The PEG 6000-stabilized nanoformulation achieved optimal colloidal properties (particle size: 65 ± 15 nm, PDI: 0.19 ± 0.03, and zeta potential: −29.6 ± 2.1 mV) alongside sustained Fickian release. Nanoencapsulation markedly suppressed key target genes (toxA, exoS, algD, papC, fimH, and cna;p< 0.05). Broth microdilution confirmed substantial antibacterial enhancement, where the optimized nanoformulation (F3) achieved an 8-fold reduction in MIC/MBC values (15.6 µg/mL vs. 125 µg/mL for crude extract) across S. aureus, E. coli, and P. aeruginosa. In LPS-stimulated RAW 264.7 macrophages, nanoformulations F2 and F3 significantly decreased TLR-2 levels from 5.99 to 5.21 and 5.18, and IL-17 expression from 2.54 to 1.87 and 1.85, respectively. Similarly, NF-κB expression dropped from 3.12 in the LPS group to 2.34 (F2) and 2.27 (F3) (p= 0.0149), confirming pronounced attenuation of acute inflammatory signaling. Conclusions: Polymeric nanoencapsulation of Euphorbia tirucalli extract successfully enhanced antibacterial efficacy and attenuated inflammatory cascades, demonstrating improved in vitro biocompatibility in macrophage cultures. The optimized formulation (F4) achieved an 8-fold reduction in MIC/MBC thresholds (15.6 µg/mL) alongside the downregulation of biofilm and virulence determinants (fimH, papC, and algD). Furthermore, the nanosystems effectively suppressed pro-inflammatory signaling in LPS-stimulated RAW 264.7 macrophages via the TLR-2/NF-κB axis. Overall, this nanoplatform demonstrates improved cellular compatibility and functions as an effective candidate for dual antibacterial and anti-inflammatory interventions.

Antibiotics doi: 10.3390/antibiotics15111066

Authors: Shun Zhang Rui Liu Zhongfu Wang Xiaofang Zhou Zhengjie Li Lei Huang Tao Pan Xudong Wen

Background: Early antibiotic administration is a cornerstone of sepsis management, but its survival benefit in septic patients with pre-existing cirrhosis remains unclear. This study evaluated the association between antibiotic timing and short-term mortality, and explored clinical indicators that modify this therapeutic effect. Methods: This multicenter retrospective cohort study used MIMIC-IV as the primary cohort (n = 1660) and subsequently evaluated consistency in MIMIC-III (n = 1776), Chengdu First People’s Hospital (n = 176), and NWICU (n = 88). Adult patients with sepsis and cirrhosis who reached the ICU without documented prior antibiotic administration were included (excluding those with pre-ICU antibiotics or ICU stay < 24 h). Antibiotic timing was dichotomized as early (≤2 h) vs. delayed (>2 h) from ICU admission. Propensity score matching balanced confounders. The primary outcome was 30-day mortality. Results: In the matched primary cohort, early antibiotics showed no overall survival benefit. However, machine learning prioritized INR, PT, and MELD-Na as potential modifiers. In exploratory analyses, lower adjusted odds of mortality were observed within specific data-derived exploratory ranges: INR 0.9–2.3 (adjusted risk difference [ARD] −11.62%, 95% CI −19.11% to −4.13%), PT 9.4–25.0 s (ARD −12.21%, 95% CI −19.70% to −4.73%), and MELD-Na 6.0–28.3 (ARD −10.88%, 95% CI −19.26% to −2.49%). A composite score (0–100) was derived; lower adjusted odds were observed in patients with score < 23.7 (OR 0.51, 0.300–0.820), whereas no association was observed in those with higher scores. Directional consistency for the exploratory composite score threshold was observed in MIMIC-III and the CD-FH external cohort, but not in the smaller NWICU cohort, underscoring the exploratory nature of these external assessments. Conclusions: Early antibiotic administration was not associated with improved short-term survival in the overall cohort of septic patients with cirrhosis, though exploratory analyses suggest that the association of timing may vary with underlying liver disease severity and coagulation abnormalities. Importantly, our findings are strictly confined to patients surviving the initial hyperacute ICU resuscitation phase (≥24 h). Given the observational design, these results remain hypothesis-generating and warrant prospective validation prior to clinical translation.

Antibiotics doi: 10.3390/antibiotics15111065

Authors: Edrous Alamer Hazem Mathkour Majed A. Suwaydi

Background: Antimicrobial resistance (AMR) is a major challenge among hospitalized patients, particularly when bacterial infection coexists with laboratory evidence of organ dysfunction. This study assessed AMR patterns and laboratory abnormality burden among hospitalized patients in Jazan, Saudi Arabia. Methods: This retrospective single-center study included 43 hospitalized patients with a culture-positive bacterial isolate and antimicrobial susceptibility testing (AST) results at King Fahd Central Hospital, Jazan, Saudi Arabia, from 1 January 2019 to 1 January 2022. Demographic, ward, organism-identification, antimicrobial susceptibility, hematological, coagulation, and biochemical data were analyzed. Only AST results for agents applicable to the identified organism were analyzed. Multidrug resistance (MDR) was primarily defined as non-susceptibility to at least one antimicrobial agent in three or more antimicrobial categories, with intermediate and resistant results grouped as non-susceptible. An alternative resistance-based sensitivity analysis classified isolates as MDR when resistance was detected to three or more individual antimicrobial agents, regardless of antimicrobial category. Laboratory abnormalities were classified using institutional reference ranges, with sex-specific hemoglobin intervals and a random-glucose threshold of >140 mg/dL. Results: The median age was 41 years (IQR, 28.0–58.5), and 22 patients were female (51.2%). The most frequent admission locations were the intensive care unit (27.9%), female medical ward (20.9%), and male neurology ward (20.9%). Gram-negative bacilli accounted for 60.5% of the total isolates. The most common organisms were Staphylococcus epidermidis (20.9%), Klebsiella pneumoniae (20.9%), and Acinetobacter baumannii complex (16.3%). MDR was identified in 30/43 isolates (69.8%) using the primary class-based non-susceptibility definition and in 30/43 isolates (69.8%) using the alternative resistance-based definition. All MDR-stratified clinical and laboratory comparisons were based on the primary class-based definition. High resistance rates were observed for oxacillin (11/11 staphylococci, 100%), erythromycin (81.2%), levofloxacin (61.1%), imipenem (56.0%), ceftazidime (53.8%), meropenem (50.0%), and cefepime (50.0%) among the tested isolates. No resistance was detected to vancomycin, teicoplanin, or tigecycline. Laboratory abnormalities were frequent, including anemia (73.8%), leukocytosis (33.3%), platelet abnormalities (47.6%), hyperglycemia (27.9%), elevated blood urea nitrogen (BUN) (67.4%), elevated creatinine (32.6%), hypoalbuminemia (71.4%), and elevated INR (52.9%). In exploratory MDR-stratified comparisons (30 MDR vs. 13 non-MDR), platelet counts were lower in the MDR group (p = 0.032), but no laboratory difference remained significant after correction for multiple comparisons, and these comparisons were underpowered, so the absence of significant differences does not exclude an association. Conclusions: Hospitalized patients in this cohort showed a high burden of AMR and frequent hematological, renal, metabolic, hepatic, and coagulation abnormalities. These descriptive findings highlight the need for denominator-aware, organism-specific AMR surveillance; whether integrating routine laboratory biomarkers into antimicrobial stewardship improves outcomes was not evaluated and requires a prospective study. Larger multicenter studies are needed to determine whether the MDR phenotype independently predicts adverse clinical outcomes.

Antibiotics doi: 10.3390/antibiotics15111064

Authors: Nuwan Indika Millagaha Gedara Lisa A. Tell Remya Ampadi Ramachandran Jim E. Riviere Raghavendra G. Amachawadi Melissa A. Mercer Douglas Shane Majid Jaberi-Douraki

Background/Objectives: Fluoroquinolones are classified by the World Health Organization as highest-priority critically important antimicrobials, and their use in food-producing animals is a One Health concern. We aimed to map the published literature on fluoroquinolones in food-producing animals and to extract the dosing regimens and reports of resistance it contains. Methods: We screened 77,583 Scopus records (1981–2021) and applied natural language processing, combining named-entity recognition with rule-based pattern matching, to 14,417 abstracts on cattle, pigs, poultry, sheep, and goats. Extraction was validated against a blinded manual annotation of 205 records, and temporal trends and between-species differences were assessed with Mann–Kendall and Kruskal–Wallis tests. Results: Extraction achieved an overall precision of 0.80, recall of 0.70, and F1-score of 0.75. Annual publications increased steadily (Mann–Kendall τ = 0.98, p < 0.001), led by authors affiliated with institutions in the United States, China, and India. Across 531 doses from 370 records, the median reported dose was 10 mg/kg in poultry and 5 mg/kg in cattle, pigs, sheep, and goats (p < 0.001); 67% of doses came from pharmacokinetic or residue studies. The proportion of records reporting fluoroquinolone resistance rose from 13% in the 1990s to about 20% after 2000 and has since remained stable, most often for ciprofloxacin with Escherichia coli, Campylobacter, and Salmonella. Conclusions: Natural language processing can map dosing and resistance information in the veterinary literature at scale. These outputs describe research activity and reported regimens, not fluoroquinolone consumption or resistance prevalence, and are best interpreted alongside national sales and surveillance data.

Antibiotics doi: 10.3390/antibiotics15111062

Authors: Fizza Khalid Ahmed J. Alzahrani Majed Alabdulhafid Gharam Alruwaili Nouf Alrakaf Osamah T. Khojah

Background: Klebsiella pneumoniae is a leading cause of multidrug-resistant Gram-negative infections worldwide, with carbapenem resistance posing a major therapeutic challenge. Continuous surveillance of antimicrobial resistance is essential to guide empirical therapy, optimize antimicrobial stewardship, and inform infection prevention strategies. Methods: We conducted a retrospective study of 2014 calendar-year patient-level non-duplicate K. pneumoniae isolates collected between 2020 and 2024 at a tertiary care hospital in Riyadh, Saudi Arabia. Only the first isolate of each species per patient per calendar year was included, regardless of specimen source or susceptibility profile. Antimicrobial susceptibility was assessed against 12 antibiotics. Temporal resistance trends were evaluated, and multivariable logistic regression assessed the association between patient setting and resistance, adjusting for study year and specimen source. Results: A total of 415 isolates (20.6%) exhibited an extended-spectrum beta-lactamase (ESBL) phenotype and 55 isolates (2.7%) met the study definition of CRKP. Co-trimoxazole showed a significant decreasing temporal trend after Benjamini–Hochberg correction. Imipenem and meropenem resistance increased from 2.3% in 2020 to 5.3% in 2024; their raw trend p-values were significant, but neither remained significant after multiple-testing correction (BH-adjusted p = 0.055). Inpatient isolates had higher adjusted odds of resistance for all 12 antibiotics. Conclusions: Resistance to several beta-lactams and fluoroquinolones remained substantial. The higher carbapenem resistance observed in 2024 warrants continued surveillance, while interpretation of temporal changes should account for multiple-testing correction and breakpoint revisions during the study period.

Antibiotics doi: 10.3390/antibiotics15111063

Authors: Ricardo Antonio Pilegi Sfaciotte Leandro Parussolo Fernanda Danielle Melo Naiara Dognani Israel Luis Henrique Pompelli Fabiano Zanini Salbego Sandra Maria Ferraz

Background/Objectives: Hospitalized companion animals may act as reservoirs of multidrug-resistant (MDR) Gram-negative bacteria and contribute to the dissemination of clinically important antimicrobial resistance genes. This study investigated gastrointestinal colonization by carbapenem-resistant Gram-negative bacteria harboring carbapenemase and/or AmpC β-lactamase genes in dogs and cats admitted to a Brazilian veterinary teaching hospital. Methods: Rectal swabs were collected from 106 animals at admission and discharge. Isolates were identified by biochemical methods and MALDI-TOF, screened by multiplex PCR for carbapenemase and AmpC β-lactamase genes, and characterized by antimicrobial susceptibility testing. Results: Fourteen (13.2%) animals were colonized, including animals colonized at admission, those in which colonization was detected only at discharge, and those remaining colonized throughout hospitalization, yielding 18 Gram-negative isolates from five bacterial species. blaNDM predominated (61.1%), followed by blaKPC, blaOXA-48-like, and blaSPM (16.7% each). PCR-based detection indicated the co-occurrence of carbapenemase and AmpC β-lactamase gene families in 66.7% of isolates, including uncommon combinations such as blaKPC + blaSPM and blaOXA-48-like + blaPER + blaEBC in Pseudomonas aeruginosa, without sequence-level confirmation. All isolates were MDR. Conclusions: Hospitalized companion animals may serve as reservoirs of clinically important MDR Gram-negative bacteria carrying carbapenemase and β-lactamase AmpC genes. These findings highlight the role of veterinary hospitals in the epidemiology of antimicrobial resistance and reinforce the need for molecular surveillance, antimicrobial stewardship, and infection prevention within a One Health framework.

Antibiotics doi: 10.3390/antibiotics15111061

Authors: Antonio Scarano Fabio Di Carlo Sergio Alexandre Gehrke Guia Basoccu Faroni Fulvio Caracciolo

Healthcare-Associated Infections (HAIs) are among the leading causes of morbidity and mortality in critically ill patients admitted to intensive care units. The growing spread of multidrug-resistant (MDR), extensively drug-resistant (XDR), and totally drug-resistant (TDR) microorganisms is making the clinical management of sepsis and septic shock increasingly complex. AIM: We conducted an uncontrolled retrospective before-and-after study comparing ICU patients admitted before and after implementation of the P-GRISS protocol (Prevention and Rapid Management of Infections and Sepsis), based on four integrated strategies: environmental prevention, microbiota restoration, rapid point-of-care molecular diagnostics, and early targeted antimicrobial therapy. Methods: We carried out a retrospective study between 1 January 2015 and 31 March 2019 at the Anesthesia and Intensive Care Unit of Sora Hospital, Italy. Results: The introduction of advanced air purification systems led to a 64% reduction in healthcare-associated Acinetobacter baumannii infections and a 76% reduction in Pseudomonas infections, with no cases of cross-transmission of Staphylococcus or Clostridioides difficile reported during the observation period. The use of the FilmArray molecular platform allowed pathogen identification in about one hour, facilitating the early initiation of targeted therapies. Sepsis-attributable mortality (calculated on the total ICU-admitted population, including deaths occurring outside the ICU) decreased from 13.5% to 7.0% (p < 0.004). Conclusions: The implementation of the P-GRISS bundle was associated with a reduction in HAIs. However, the relative contribution of environmental purification, rapid diagnostics, microbiota restoration, and antimicrobial optimization cannot be determined from the present study.

Antibiotics doi: 10.3390/antibiotics15111060

Authors: Michiko Kawanishi Taimu Toyama Yuta Hosoi Tomoko Tanaka Tomoko Funakoshi Saki Harada Niho Fujiwara Shunya Okamura Manao Ozawa Mari Matsuda Hideto Sekiguchi

Background/Objectives: Colistin, previously of limited clinical relevance in human medicine, has become one of the last-line antimicrobials for infections caused by multidrug-resistant Gram-negative bacteria and was classified by the World Health Organization as a highest-priority critically important antimicrobial (HPCIA) in 2017. In Japan, based on a risk assessment, risk-management measures for colistin were strengthened in 2018 by revoking its designation as a feed additive and restricting its veterinary medicinal use to second-line treatment. This study evaluated changes in colistin sales volume and resistance among Escherichia coli from pigs and characterized mcr-1-carrying isolates. Methods: A total of 2212 E. coli isolates collected through the Japanese Veterinary Antimicrobial Resistance Monitoring System (JVARM) from healthy pigs at slaughterhouses (n = 1122) and diseased pigs submitted for pathological inspection (n = 1090) during 2013–2023 were subjected to antimicrobial susceptibility tests. Isolates with colistin minimum inhibitory concentrations of at least 4 μg/mL were screened for mcr-1 to mcr-10. Long-read whole-genome sequencing was performed for 32 mcr-1-positive isolates. Results: Colistin resistance rate among isolates from diseased pigs decreased from 52.0% in 2017 to 7.7% in 2023, whereas resistance among isolates from healthy pigs remained at or below 6.0% throughout the study period. mcr-1 was the predominant mobile colistin resistance gene. ST88, ST100, and ST1 were the predominant sequence types among isolates from diseased pigs, whereas healthy-pig isolates exhibited greater sequence-type diversity. IncI2 was the dominant mcr-1 plasmid type, and all IncI2 plasmids were predicted to be conjugative. Their backbones were highly similar to pHNSHP45, an IncI2 plasmid identified in an E. coli isolate collected from a pig in China in 2013, retained pil and tra/vir regions, and generally lacked ISApl1. Conclusions: The strengthening of risk-management measures in 2018 was followed by a substantial decline in colistin resistance rate among isolates from diseased pigs, supporting the effectiveness of these measures. Stable and potentially transmissible IncI2 plasmids continue to maintain mcr-1, underscoring the importance of maintaining these risk-management measures, ensuring prudent antimicrobial use, and continuing integrated phenotypic and genomic surveillance.

Antibiotics doi: 10.3390/antibiotics15111059

Authors: Andrea Sambri Alessandro Bruschi Martina Modeo Eleonora Zamparini Sara Tedeschi Giacomo Fornaro Marta Stoppa Cristina Scollo Lorenzo Di Prinzio Andrea Pace Pierluigi Viale Massimiliano De Paolis

Background: Determining infection eradication before reimplantation remains challenging during two-stage revision for chronic periprosthetic joint infections (PJI). This exploratory study investigated the association between serial postoperative C-reactive protein (CRP) trajectories and treatment outcome following prosthesis explantation during two-stage revision for chronic periprosthetic joint infection (PJI). Methods: We retrospectively reviewed patients undergoing two-stage revision for chronic hip or knee PJI between January 2020 and August 2024. Patients with weekly CRP measurements and at least 12 months of follow-up were included. Treatment failure was defined according to modified Delphi criteria. Weekly CRP concentrations and percentage changes from postoperative Week 1 (ΔCRP) were compared between groups. ROC analysis assessed CRP discrimination weekly. Results: Ninety-one patients were included; 50 (54.9%) achieved infection eradication and 41 (45.1%) experienced treatment failure. CRP increased during the first post-operative week in both groups. Week 1 CRP concentrations were not significantly different between groups (5.24 vs. 6.79 mg/dL, p = 0.108). From Week 2 onwards, postoperative CRP trajectories and relative reductions from Week 1 differed between patients with treatment success and those experiencing treatment failure. From Week 2 onward, CRP remained significantly higher in patients with treatment failure (Week 2: 3.91 vs. 2.27 mg/dL, p = 0.0017; Week 4: 3.28 vs. 0.94 mg/dL, p < 0.0001; Week 6: 2.16 vs. 0.70 mg/dL, p = 0.0007). Relative CRP reduction was significantly higher in the success group from Week 2 onward. Discriminatory performance improved over time, with AUCs of 0.699–0.782 at Weeks 2–6. Conclusions: In this exploratory cohort, postoperative CRP trajectories differed according to treatment outcome. A slower decline in CRP was associated with treatment failure, but these findings do not establish an independent prognostic effect. CRP should not determine reimplantation timing in isolation, but an unfavourable trajectory should prompt reassessment and consideration of repeat debridement and spacer exchange. Larger prospective multicentre studies are needed to confirm these associations and determine their clinical utility.

Antibiotics doi: 10.3390/antibiotics15111058

Authors: Michał Powietrzyński Jan Romantowski Julia Glińska Ilona Iwaszko Joanna Pawlik Nicola Le Alicja Miecznikowska Dominika Galińska Maja Kozielec Kaja Kozielec Joanna Śledzik Natalia Domańska Mateusz Skotnicki Agata Sztramska Marta Chełmińska Marek Niedoszytko

Background: Beta-lactam antibiotic allergy is one of the most frequently reported drug hypersensitivities. True allergy is rarely confirmed. Inaccurate labeling leads to unnecessary avoidance of beta-lactams, antimicrobial resistance, and increased healthcare costs. Delabeling is mainly evaluated using electronic databases, whereas patient perceptions, quality of life, and real-world barriers remain uncertain. Methods: This cross-sectional, questionnaire-based study included 96 adults with a reported history of beta-lactam hypersensitivity: 46 after successful specialist delabeling and 50 before specialist evaluation. Structured telephone interviews assessed diagnostic pathways, perceived correctness of diagnosis or exclusion, confidence in beta-lactam safety, antibiotic use, and symptom recurrence. Quality of life was assessed using the WHOQOL-BREF questionnaire. Results: Perceived safety of beta-lactam antibiotics was significantly higher in the delabeled group than in the non-delabeled group (7.37 vs. 2.40; p < 0.001). WHOQOL-BREF scores were similar between groups, except for a small difference in the Environment domain, favoring delabeled (p = 0.029) patients. Among delabeled patients, 57% required antibiotics during follow-up; of these, 65% received beta-lactams. In 35% of cases with an indication, physicians withheld beta-lactams despite documented delabeling. Self-reported mild cutaneous symptoms occurred in 18% of patients re-exposed to beta-lactam antibiotics despite delabeling; the significance of this finding needs to be assessed in the future. Conclusions: Patients who underwent beta-lactam allergy delabeling reported greater perceived safety regarding the use of beta-lactam antibiotics, while no significant differences in quality of life were observed. Persistent reluctance among patients and physicians may, however, limit the real-world benefits of delabeling.

Antibiotics doi: 10.3390/antibiotics15111057

Authors: Gloria Bua Davide Campoccia Giulia Bottau Stefano Ravaioli Eleonora Capponi Maria Daglia Carla Renata Arciola

Acinetobacter baumannii (AB) is recognized as a major opportunistic nosocomial pathogen. Its success largely depends on the ability to adhere to and colonize both biotic and abiotic surfaces, survive under adverse environmental conditions, and acquire antimicrobial resistance determinants. In orthopedic settings, its ability to form biofilms is a key virulence factor that contributes to the development of implant-associated infections. Although Gram-positive bacteria remain the leading etiologic agents of orthopedic implant infections, the increasing emergence of multidrug-resistant isolates of this Gram-negative bacterium in periprosthetic tissues and other implant-associated niches has become a major clinical concern. The intrinsic antibiotic tolerance of biofilm-embedded bacterial cells and the multidrug resistance of AB render these infections difficult to eradicate. We conducted a scoping review to summarize the current evidence on the role of AB in orthopedic implant-related infections, with emphasis on its epidemiology, clinical management, biofilm formation on abiotic surfaces, and emerging anti-biofilm and other preventive strategies. A deeper understanding of these aspects is essential to better delineate the pathogenic potential of AB and to support the development of more effective approaches for the prevention and management of orthopedic implant-associated infections.

Antibiotics doi: 10.3390/antibiotics15111056

Authors: Igor Lima Soares João Fundo Redondo Joana Liberal Francisco Leandro Rocha Liberato Kirley Marques Canuto Mary Anne Medeiros Bandeira Lígia Salgueiro Mónica Zuzarte

Background/Objectives: Dermatophytosis is a common superficial mycosis of keratinized tissues caused predominantly by species of the genera Epidermophyton, Microsporum, and Trichophyton. The present study aimed to investigate the antidermatophytic efficacy and skin reparative potential of essential oils from Lippia alba chemotypes. Methods: Essential oils from two L. alba chemotypes collected during the dry season in Fortaleza, Ceará, Brazil, were evaluated for their in vitro antifungal activity against clinical and reference strains. The essential oil showing the highest antifungal activity was subsequently evaluated in antibiofilm, cytotoxicity, and fibroblast wound-closure assays, as well as in an ex vivo human skin model of Trichophyton rubrum infection. Results: Chemotype I, rich in citral and α-copaene, and chemotype II, rich in citral and limonene, both demonstrated antidermatophytic activity. However, chemotype II showed greater efficacy, with a minimum inhibitory concentration as low as 12.5 μg/mL. This oil was more effective at preventing early biofilm development than disrupting mature biofilms. It also exhibited low cytotoxicity, was associated with enhanced wound closure, and reduced fungal colonization and lesion development in the skin, particularly as a preventive strategy. Conclusions: L. alba citral–limonene chemotype showed promising antidermatophytic activity and effects associated with wound closure and reduced fungal progression in the models evaluated, supporting its potential as a candidate for further investigation in topical approaches to dermatophytosis.

Antibiotics doi: 10.3390/antibiotics15111055

Authors: Meryem Toprak Tuncer Tuba Bayir Ahmet Atessahin

Background/Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) remains an important One Health challenge, yet its combined human, animal, and environmental correlates remain incompletely understood. This study examined associations of human antibiotic consumption, veterinary antimicrobial sales, pig and poultry density, and pesticide use with the proportion of methicillin resistance among invasive S. aureus isolates (MRSA proportion) across 27 European Union countries. Methods: Country-level panel data (2013–2023, 297 country-year observations) were analyzed using two-way fixed-effects regression with Driscoll–Kraay standard errors, a Spatial Lag of X (SLX) model, and Global/Local Moran’s I statistics. Results: Human antibiotic consumption showed the most consistent positive association with MRSA (β = 0.523, p < 0.001), remaining significant in the SLX model, across alternative spatial weights, and in models for proportional outcomes, as did the local association of pig density. Pesticide use showed a negative within-country association (β = −0.189, p = 0.015) that was not retained in fractional logit models and, in the primary SLX model, a positive spillover association (θ = 1.097, p < 0.001) that was sensitive to the spatial-weight specification. Veterinary antimicrobial sales showed a positive total effect across all spatial weight specifications, whereas the poultry density spillover was not robust. MRSA exhibited persistent positive spatial clustering (Moran’s I = 0.481–0.558; all p = 0.001), with High–High clusters in southeastern and Low–Low clusters in northern Europe. Conclusions: At the country level, human antibiotic consumption was most consistently associated with MRSA proportion, whereas pesticide- and poultry-related spillover associations were specification-dependent. These ecological associations should be regarded as hypothesis-generating; nevertheless, they support integrated, cross-border One Health surveillance of antimicrobial resistance.

Antibiotics doi: 10.3390/antibiotics15111054

Authors: Matheus Alves Pauletti Marcelly Chue Gonçalves Sara Scandorieiro Leonardo Pinto Medeiros Laura Pierobão Anastácia Nikolaos Deonas Renata Katsuko Takayama Kobayashi Gerson Nakazato

Background/Objectives: Resistance and toxicity limit topical agents for infected burns. We evaluated biogenic silver nanoparticles (bio-AgNPs) combined with Brazilian stingless bee Scaptotrigona bipunctata honey (SB honey). Methods: Bio-AgNPs and honeys from three stingless bee species and Apis mellifera were screened against 11 reference and multidrug-resistant (MDR) strains, including MRSA, MDR Escherichia coli, and MDR Pseudomonas aeruginosa. The most active, SB honey, was combined with bio-AgNPs and assessed by checkerboard (FICI), time-kill, and scanning electron microscopy (SEM). Each agent’s cytotoxicity was determined in HaCaT keratinocytes. Results: Combinations were synergistic (FICI 0.50) against the three Gram-negative strains tested and additive (FICI 0.75) against the three Gram-positive ones, lowering both inhibitory concentrations up to fourfold. The combination reduced viable counts below detection faster than either agent alone at its MBC against MDR P. aeruginosa (30 vs. 60 min) and S. aureus (7 vs. 10–24 h), and matched the fastest single agent against E. coli, at two- to fourfold lower concentrations of both. SEM showed surface damage and incomplete septa. These reduced concentrations fell below each agent’s CC50, increasing the calculated selectivity index. Conclusions: Bio-AgNPs and SB honey act jointly against the reference and MDR strains tested, all associated with burn infections, at concentrations below each agent’s cytotoxic threshold, supporting their further development as a topical antimicrobial.

Antibiotics doi: 10.3390/antibiotics15111053

Authors: Mariana Aparecida Piotto Gumiero Jennifer Germiniani-Cardozo Débora Dahmer Pedro Henrique Takata Pedro Ademario Lima e Silva Eliana Carolina Vespero Sara Scandorieiro Renata Katsuko Takayama Kobayashi Gerson Nakazato

Background/Objectives: Bacterial resistance to antimicrobials has become a public health problem worldwide, limiting the effectiveness of conventional treatments. Therefore, combination antimicrobial therapy has been proposed as a strategy to combat multidrug-resistant bacteria. This study aimed to investigate the antibacterial effects of ciprofloxacin (CIP) in binary combinations with Cinnamomum cassia (L.) J. Presl. (CEO) and Origanum vulgare L. (OEO) essential oils against Acinetobacter baumannii, Klebsiella quasipneumoniae, Pseudomonas paraeruginosa, Staphylococcus aureus, and methicillin-resistant S. aureus (MRSA). Methods: The hemolytic activity was evaluated for the compounds individually and when combined. The antimicrobial activity was performed by broth dilution in double-antimicrobial gradient and time-kill assays. Results: The CEO–CIP and OEO–CIP combinations demonstrated hemolytic activity in human erythrocytes of 4.04 to 3.35% and 3.39 to 2.29%, respectively, and presented synergistic, additive, and indifferent antibacterial effects. The CEO–CIP combination significantly reduced CIP minimal inhibitory concentration from 256 to 0.125 µg/mL against MRSA. OEO–CIP was bactericidal against P. paraeruginosa and S. aureus; meanwhile, the CEO–CIP combination showed bactericidal activity against P. paraeruginosa, but reduced S. aureus viability by only 1.83 log after 24 h. Conclusions: These findings demonstrate the combination of CEO–CIP against A. baumannii, K. quasipneumoniae, P. paraeruginosa, S. aureus, and MRSA, in addition to hemolytic activity below 5% at the tested concentrations. Although limited to in vitro conditions, these results highlight the combination’s therapeutic potential and emphasize the necessity for further investigation into its mechanisms of action and in vivo toxicity.

Antibiotics doi: 10.3390/antibiotics15111052

Authors: Siyi Hu Ying Zhang Yuanye Zeng Shizhou Shen Rui Xin Keqiang Zhang Fengxia Yang

Background/Objectives: The proliferation of antibiotic resistance genes (ARGs) in agricultural soils poses a growing One Health threat. However, how hydrological fluctuations in paddy–upland rotations shape the soil resistome remains unclear. This study examined the spatiotemporal dynamics and drivers of soil ARGs in a manure-amended rice–faba bean rotation system. Methods: A one-year field experiment was conducted using quantitative PCR and 16S rRNA gene sequencing to characterize ARGs, mobile genetic elements (MGEs), and bacterial communities. Results: The hydrological regime and manure application interactively drove resistome succession. Manure introduced diverse ARGs and MGEs, whereas redox fluctuations restructured bacterial host communities and ARG–MGE networks. Compared with the wet phase, the dry phase enriched intI1 by approximately two orders of magnitude. Specifically, the log10-transformed intI1/16S rRNA gene copy-number ratio increased from −7.11 to −5.14, indicating greater potential for horizontal gene transfer. The fallow transition period represented a critical resistome-restructuring stage with lasting legacy effects. Structural equation modeling identified a dominant carbon–microbe–MGE cascade. Active organic carbon fractions, including dissolved organic carbon (DOC) and readily oxidizable carbon (ROC), shaped microbial community structure, which regulated MGE abundance and ultimately ARG dynamics. MGEs were the strongest direct driver of ARGs (path coefficient = 0.575, p < 0.001). Conclusions: Wet–dry alternation modulates soil resistance risks through the carbon–microbe–MGE cascade. The fallow transition period therefore provides a key target for managing hydrology and carbon inputs to mitigate ARG dissemination in sustainable agroecosystems.

Antibiotics doi: 10.3390/antibiotics15111051

Authors: Irene Sini Lucia Allavena Niccolò Riccardi Giovanni Fumagalli Alice Claudia Repossi Maurizio Ferrarese Marco Mantero Mariangela Valentina Puci Giovanni Sotgiu Francesco Blasi Luigi Ruffo Codecasa

Background/Objectives: Tuberculosis (TB) in older adults represents an increasing clinical challenge, although this population remains underrepresented in clinical studies. We compared outcomes and permanent regimen modification between age groups in adults treated for drug-susceptible pulmonary TB. Methods: This retrospective study included 3621 consecutive adults treated at an Italian referral centre between 2000 and 2023. Patients were stratified as <65 and ≥65 years for the primary analysis; additional analyses used four age groups and continuous age. Logistic regression models were adjusted for sex, WHO region, socio-economic status, clinical setting, and calendar period. Results: There were 3173 patients aged <65 years and 448 aged ≥65 years. Crude treatment success was similar (90.0% vs. 89.3%; p = 0.65), whereas death during treatment was more frequent among older adults (4.7% vs. 0.3%; p < 0.001) and loss to follow-up among younger adults (6.0% vs. 2.0%; p < 0.001). After adjustment, age ≥65 years was associated with lower odds of treatment success (aOR 0.56, 95% CI 0.39–0.81) and higher odds of death (aOR 12.24, 95% CI 4.83–31.00). Compared with patients aged 65–79 years, those aged ≥80 years had lower adjusted odds of success (aOR 0.41, 95% CI 0.22–0.78; Holm-adjusted p = 0.025) and higher odds of death (aOR 4.49, 95% CI 1.78–11.28; Holm-adjusted p = 0.004). Permanent regimen modification did not differ between the two main age groups (3.8% vs. 4.7%; p = 0.34). Conclusions: Increasing age was associated with lower treatment success and higher mortality, particularly among adults aged ≥80 years, supporting closer clinical monitoring in this population.

Antibiotics doi: 10.3390/antibiotics15111050

Authors: Manal Rossi Moussa Benboubker Salim Belchkar Fouzia Hmami Bouchra Oumokhtar

Background/Objectives: Peripheral intravenous catheters (PIVCs) are frequently used in neonatal intensive care units (NICUs) and can become major conduits of nosocomial infections, often colonized with clinically important bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). Molecular data on PIVC-associated S. aureus in Moroccan NICUs remain limited. This study aimed to characterize bacterial colonization of PIVCs and investigate the phenotypic and molecular characteristics of recovered S. aureus, with particular emphasis on MRSA and staphylococcal cassette chromosome mec (SCCmec) types. Methods: 402 PIVC tips collected from 225 neonates hospitalized in the NICU of Hassan II University Hospital between June 2024 and May 2025 were analyzed using the Brun–Buisson quantitative culture method. Bacterial identification and antimicrobial susceptibility testing were performed, and S. aureus isolates were further characterized by PCR for 16S rRNA, mecA, and Panton–Valentine leukocidin (PVL) genes. SCCmec typing was performed on mecA-positive MRSA isolates. Results: Seventy-nine PIVC tips (19.7%, 95% CI: 16.1–23.8%) met the colonization criteria (≥1000 CFU/mL). A total of 152 bacterial isolates were recovered; S. aureus was the predominant species (n = 89, 58.6%), of which 15 (16.9%) were confirmed as MRSA. All MRSA isolates were mecA-positive. SCCmec typing identified two types; 12 isolates predominated and harboured SCCmec type IV (n = 12, 80.0%), while SCCmec type III was detected in three isolates (20.0%). No isolate harbored PVL genes, and no inducible clindamycin resistance was detected. MRSA isolates showed markedly higher resistance to gentamicin, fusidic acid, erythromycin, rifampicin, and clindamycin compared with MSSA isolates. Conclusions: S. aureus was the predominant bacterium recovered from PIVCs in our study. The predominance of SCCmec type IV among MRSA isolates provides original molecular epidemiological data from a Moroccan neonatal setting and highlights the need for continued surveillance of PIVC-associated MRSA and its molecular characteristics.

Antibiotics doi: 10.3390/antibiotics15111049

Authors: Elisabeth Fischer Isabella Salihovic Anabel Cenit Andreas Kubin Lionel Wightman Linda Jernej Kristjan Plaetzer

Background/Objectives: Curcumin is a food-grade (E100) photosensitiser with promising antimicrobial properties, but its applicability is limited due to low water-solubility. Complexation of curcumin with hydroxypropyl-γ-cyclodextrin (HP-γ-CD) overcomes this constraint and may facilitate using a single photosensitiser for Photodynamic Inactivation (PDI) of pathogens along the food-production chain and within a One Health framework. Methods: In this study, a novel method to complex HP-γ-CD and curcumin (abbreviated as CD-Cur) was developed and the compound was tested against Escherichia coli, Salmonella enterica, and Candidozyma auris, in liquid culture and in situ on abiotic surfaces, food matrices, and a porcine skin model. Results: Planktonic experiments demonstrated concentration-dependent PDI efficacy with photokilling exceeding the 3 log10 threshold for all tested organisms at CD-Cur concentrations between 10 and 50 µM, illuminated with 435 nm (50 J/cm2) LED light, while dark and light toxicity remained below microbiologically relevant levels. CD-Cur induced high reductions of viable E. coli on food-contact plastic foil (3.35 log10, 100 µM, white light, 100 J/cm2) and on abiotic surfaces (5.17–5.50 log10, 30 µM, 435 nm, 25 J/cm2) with visible photobleaching of the photosensitiser after illumination. On salmon and pistachios, matrix-dependent effects were observed, but PDI still achieved practically relevant reductions (2.25–3.52 log10, 30 µM, 435 nm, 200 J/cm2) of S. enterica without visible colour alteration of the food. In a porcine skin model, CD-Cur in a 1% hydroxyethyl cellulose hydrogel reduced C. auris contamination notably. The addition of 2 mM EDTA further enhanced antifungal effects, indicating that CD-Cur can also be applied in a medical context as topical application on porcine skin (2.41 log10, 500 µM, 435 nm, 75 J/cm2). Conclusions: Together, these results show that a single, photodynamic system based on food-grade CD-Cur can provide broad antimicrobial efficacy across diverse matrices and pathogens in a One Health context.

Antibiotics doi: 10.3390/antibiotics15111048

Authors: Lingxia Zhang Weiguo Sun Yanhua Liu Wenping Gong

Latent tuberculosis infection constitutes the principal reservoir from which tuberculosis (TB) disease emerges, yet the molecular transition from durable containment to reactivation remains incompletely resolved. Reactivation is not a single bacterial “awakening” event or a nonspecific consequence of immunosuppression. Instead, we propose a hypothesis-generating threshold framework across an interconnected pathogen–host–microenvironment system. This narrative review integrates evidence on Mycobacterium tuberculosis persistence and resuscitation programs, including metabolic remodeling, resuscitation-promoting factors, cell-wall turnover, and metal acquisition, with defects in adaptive and innate immunity, immunometabolic control, cytokine networks, aging, comorbid disease, and epigenetic regulation. We further examine the granuloma as a spatially heterogeneous ecosystem in which hypoxia, necrosis, vascular dysfunction, fibrosis, extracellular-vesicle communication, and intercellular crosstalk may influence bacterial control. Evidence from human longitudinal and cross-sectional studies is distinguished from non-human-primate, other animal, in vitro, and cross-system evidence. The proposed balance between bacillary resuscitation potential and local containment capacity has not been prospectively validated in humans or defined by a numerical clinical cutoff. Pathogen-, host-, and lesion-directed approaches are therefore discussed as research priorities. They are not alternatives to recommended TB preventive treatment for eligible individuals or antimicrobial treatment of TB disease. Prospective human validation is required before the framework can inform biomarker-guided intervention or patient stratification.

Antibiotics doi: 10.3390/antibiotics15111047

Authors: George Cosmin Nadăş Mihaela Niculae

Plant-derived phytochemicals are being investigated as antibacterial agents and antibiotic adjuvants, but disruption of bacterial redox homeostasis does not invariably lead to sustained killing. This critical narrative review examines how bacterial responses to phytochemical-induced oxidative and electrophilic stress influence antibacterial efficacy and subsequent antibiotic susceptibility. We integrate phytochemical-specific evidence with broader bacterial redox physiology, distinguishing demonstrated mechanisms from molecular associations and mechanistic extrapolations. The synthesis covers thiol modification, metal dyshomeostasis, membrane and respiratory dysfunction, redox-sensitive regulation, antioxidant defenses, repair, and metabolic remodeling. These responses, triggered by phytochemical exposure, can contribute to bacterial protection and recovery, although causal redox involvement remains unresolved in many studies. Depending on the phytocompound, bacterial species, and exposure conditions, observed outcomes include cross-protection, tolerance, persistence, viable-but-nonculturable survival, and antibiotic-specific susceptibility trade-offs. Repeated exposure may additionally select heritable changes that must be differentiated from reversible physiological adaptation. Irreversible redox collapse is interpreted operationally as sustained loss of viability and failure to recover after stress removal. The term denotes an interpretative framework rather than a distinct death mechanism; a redox-dependent contribution requires functional evidence, and recovery failure is assessed within specified assay conditions. ROS fluorescence, ATP depletion, or growth inhibition alone cannot establish this endpoint or its redox dependence. Integrating validated redox measurements and functional interventions with killing and recovery assays, chemical characterization, exposure standardization, and host tolerability can strengthen the evaluation of plant-derived antibacterial compounds and their combinations with antibiotics.

Antibiotics doi: 10.3390/antibiotics15111046

Authors: Ian T. Watkins Matthew A. Pappas Jonathan Lans Nelson Merchan Jason Young Abhiram R. Bhashyam

Objective: The primary goal of this study was to determine the rate of occult fracture-related infection associated with nonunion of upper extremity fractures following open reduction internal fixation (ORIF). Methods: We performed a retrospective analysis of patients treated for upper extremity nonunion after ORIF at five urban hospitals, including two level I trauma centers, between the years 2000 and 2020. Patient demographics, operative reports, and laboratory data were collected. An unexpected positive intraoperative culture (UPIC) was defined as a positive intraoperative culture from a nonunion without overt signs of infection. Descriptive statistics were performed. Results: Of 363 patients with an upper extremity nonunion after ORIF, 197 had culture data available. Sixty-seven percent (67%) of nonunions occurred proximal to the elbow. Positive cultures were identified in 84 patients (43%), with the distal humerus showing the highest rate (33%). A total of 51 UPICs were identified. Cutibacterium acnes was present in 48% of all culture-positive nonunions and Coagulase-negative Staphylococci (CoNS) was represented in 43% of all culture-positive nonunions. C. acnes culture positivity rates decreased by proximal-to-distal anatomic location with 100% of culture-positive clavicle nonunions sampled growing C. acnes and 25% of culture-positive ulnar nonunions growing C. acnes. Among culture-positive nonunions, 94% of the UPIC group grew C. acnes or CoNS, compared with 52% of the overt FRI (fracture-related infection) group. The posterior mean rate of UPICs, when normalized to the clavicle, ranged from 5.1% to 23.5%. The clavicle demonstrated the highest rate (0.24; 95% CI, 0.11–0.39). The distal humerus had a comparable rate (0.22; 95% CI, 0.12–0.34; normalized ratio, 0.94). Nonunions with a high pre- or intraoperative concern for infection had a 48% rate of growing virulent bacteria compared to a 6% rate in the UPIC group. Conclusions: In total, 31% of aseptic-appearing nonunions yielded positive cultures and 94% of UPICs grew predominantly low-virulence organisms. While there is a high rate of UPICs with C. acnes and Coagulase-negative Staphylococci in upper extremity nonunion, the clinical significance of UPIC FRI remains unclear. Further research is needed to determine the implications of such UPIC in the absence of overt infection.

Antibiotics doi: 10.3390/antibiotics15111045

Authors: Ron Cheah Kaleswari Somasundaram Karin Thursky Kirsty Buising Matthew Suen Leanne Teoh Lena Sanci Jo-Anne Manski-Nankervis Ruby Biezen

Background/Objectives: Antimicrobials are regularly prescribed in general practice, yet the infrastructure to support routine review of prescribing in this setting remains limited. Integrated antimicrobial stewardship (AMS) interventions combining automated auditing of routine prescribing data with an educational component are a promising approach to addressing this gap. This qualitative study aimed to explore general practitioner (GP) and practice manager (PM) perspectives on the acceptability, feasibility, and perceived effectiveness of such an intervention implemented across 31 general practices and 97 GPs in Victoria, Australia. It also explored implementation considerations relevant to future scaling of the intervention. This is one of the first studies of GP and PM perspectives on this type of integrated program. Methods: Semi-structured interviews were conducted with 17 GPs and 5 PMs and analyzed using both inductive and deductive thematic analysis. The Theoretical Domains Framework (TDF) informed interview guide development and deductive coding; themes were generated inductively and final themes mapped to the Capability, Opportunity, Motivation–Behavior (COM-B) model for presentation. Results: Four themes were identified: (1) trust, validity, and value of audit and feedback; (2) clinical judgement and patient factors in prescribing complexity; (3) social, organizational, and professional contexts of learning and behavior change; and (4) effort, usability, and workflow in engagement with the intervention. Conclusions: Participants valued AMS activities that supported reflective practice without undermining professional autonomy. Trust in the systems managing prescribing data was a precondition for engagement with the data itself. Engagement also depended on fit with existing workflows, individualized reporting, and contextualized feedback. The social conditions under which learning occurred, such as peer interaction, moderated discussion, and collaborative reflection, mattered as much as the technical components of a program.

Antibiotics doi: 10.3390/antibiotics15111044

Authors: Senamile L. Ngema Reeve Sobol Siyabonga Myawe Fay Willis Lwazi Danisa Lateef Babatunde Amusa Keeren Lutchminarain Shaheed V. Omar N. Sarita Shah Barun Mathema Neel R. Gandhi Kogieleum Naidoo Rubeshan Perumal

Background: Bedaquiline (BDQ) is critical for multidrug-resistant tuberculosis (MDR-TB) treatment, but emerging resistance threatens its efficacy. Detection of BDQ resistance relies on slow phenotypic drug-susceptibility testing (pDST), delaying treatment decisions. We determined the diagnostic accuracy of whole-genome sequencing (WGS) for predicting BDQ resistance against culture-based pDST. Methods: Mycobacterium tuberculosis isolates underwent BDQ pDST (1.0 µg/mL in MGIT) in a prospective study of patients with MDR-TB with additional resistance to fluoroquinolones or aminoglycosides in KwaZulu-Natal, South Africa (2018–2022). Isolates with single nucleotide polymorphisms showing a read depth of ≥10 and allele frequency of ≥0.7 were included. Isolates exhibiting phenotypic resistance underwent quantitative minimum inhibitory concentration (MIC) testing (ranging from 0.25 to 8.0 µg/mL) using the BACTEC MGIT 960 system. Diagnostic performance of WGS compared to MGIT-based pDST was assessed by calculating sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV). Results: Analysis included 428 isolates: 88 phenotypically resistant isolates (87 with potential BDQ-resistance-associated variants (RAVs) and one wild-type) and 340 susceptible isolates (7 with potential RAVs and 333 wild-type). Presence of potential RAVs accurately predicted phenotypic resistance: sensitivity 98.9% (95% CI: 93.8–99.8), specificity 97.9% (95% CI: 95.8–99.0), PPV 92.6% (95% CI: 85.4–96.4), and NPV 99.7% (95% CI: 98.3–99.6). Among the 94 isolates with potential RAVs, we observed gene mutations in Rv0678 (88/94, 93.6%), pepQ (2/94, 2.1%), and Rv1979c (4/94, 4.3%). The median BDQ MIC for resistant isolates was 4.0 µg/mL [IQR:2.0–4.0 µg/mL]. Conclusions: Potential BDQ RAVs, predominantly in Rv0678, are strong predictors of BDQ phenotypic resistance, highlighting the potential use of genotypic catalogues to inform timely treatment decisions.

Antibiotics doi: 10.3390/antibiotics15111043

Authors: Mark S. Butler Robert J. Capon

Fungal diseases range from common superficial infections to life-threatening invasive mycoses, yet treatment options remain constrained by host toxicity, drug interactions, pharmacokinetic limitations and antifungal resistance. This review provides a historical and chemical account of 70 synthetic antifungal therapeutic entities, including mixtures and fixed-dose combinations, introduced or approved for human use from approximately 1895 to September 2026. These entities are organised into 19 structural classes, including hydroxyquinolines, diamidines, azoles, thiocarbamates, hydroxypyridones, benzylamines, morpholines and oxaboroles. Azoles constitute the largest class, comprising 31 agents across four subclasses: one benzimidazole, 20 imidazoles, nine triazoles and one tetrazole. For each entity, we summarise its first documented introduction or approval, clinical indications, routes of administration, use status, mode(s) of action, resistance mechanisms and relevant medicinal-chemistry context. Early synthetic antifungals were predominantly topical antiseptics used for dermatological or mucosal infections. Subsequent development delivered oral and intravenous agents suitable for systemic and invasive mycoses. From 1970 onwards, azoles predominated, accounting for 30 of the 43 synthetic entities first introduced or approved for human use. Broad-spectrum activity and the availability of oral and, for selected agents, intravenous formulations transformed antifungal therapy; however, the widespread use of azoles also concentrated treatment around inhibition of fungal ergosterol biosynthesis. Many early agents are classified as discontinued, whereas azoles and selected mechanistically distinct classes remain clinically important. This review highlights the enduring contribution of synthetic medicinal chemistry to antifungal therapy and the continuing need for safer agents with new chemical scaffolds and fungal targets, reliable exposure at sites of infection and reduced vulnerability to resistance.

Antibiotics doi: 10.3390/antibiotics15101042

Authors: Fausto Catena Belinda De Simone Igor A. Kryvoruchko Salomone Di Saverio Marcelo A. F. Ribeiro Timothy Craig Hardcastle Arda Işık Orestis Ioannidis Mauro Podda Marcello Di Martino Chad G. Ball Tal M. Hörer Pablo Ottolino Jung-Min Bae Fernando J. Kim Kemal Rasa Vishal G. Shelat Pradeep Navsaria Agron Dogjani Edward Tan Francesca Dal Mas Zsolt J. Balogh Isidoro Di Carlo Guixi Zhang Jae Gil Lee Dieter G. Weber Marco Ceresoli Gary Alan Bass Fikri M. Abu-Zidan Andrey Litvin David Costa-Navarro Edoardo Picetti Ana María González Castillo Andreas Hecker Aleix Martínez-Pérez Carlos A. Ordoñez Angela Gurrado Nikolaos Pararas Carlos Augusto Gomes Marja A. Boermeester Gustavo P. Fraga Emmanouil Pikoulis Anastasia Pikouli Jim Khan Paula Ferrada Boris E. Sakakushev Michel P. J. Teuben Tadeja Pintar Kaliterna Krstina Doklestić Vasiljev José Manuel Ramia Andrew W Kirkpatrick Kenji Inaba Ernest E. Moore Walter L. Biffl Manu L. N. G. Malbrain Gia Tomadze Juan Carlos Puyana Ari Leppäniemi Michael Sugrue Imtiaz Wani Rifat Latifi Haytham M. Kaafarani Philip F. Stahel Luca Ansaloni Federico Coccolini Massimo Sartelli

Background: Procalcitonin (PCT) may support decision-making in abdominal and emergency surgery when infection is difficult to distinguish from non-infectious inflammation. Its interpretation remains challenging because clinical settings, sampling schedules, and proposed thresholds vary. This WSES position paper examines the evidence across six clinical scenarios to provide a practical framework for PCT-informed decision-making. Methods: A structured literature review covering January 1980 to December 2025, with targeted updates through August 2026, informed six PICO-based clinical questions. Evidence appraisal drew on selected GRADE domains, including consistency, directness, and precision. Recommendations were developed through iterative expert review and consensus. Results: The panel formulated six conditional recommendations addressing intra-abdominal infection diagnosis, antibiotic discontinuation after source control, suspected source-control failure, infected pancreatic necrosis, infectious complications after trauma, and postoperative anastomotic leak. The panel’s qualitative assessment rated evidence certainty as moderate for antibiotic discontinuation and the pancreatitis domain, and low for the remaining domains. Serial PCT trends may complement clinical assessment in selected patients. Evidence for reduced antibiotic exposure with predefined PCT algorithms is more established than evidence that PCT-informed imaging, reintervention, or discharge decisions improve patient outcomes. Conclusions: PCT-informed decision-making in abdominal surgery may contribute to a more individualized approach to emergency surgical care and precision emergency surgery. When interpreted as part of serial assessment and integrated with clinical judgement, organ-dysfunction trends, microbiology, imaging, and evaluation of source-control adequacy, PCT may support individualized antibiotic discontinuation, potentially earlier recognition of an unfavourable clinical course, and more timely diagnostic and source-control reassessment. Current evidence does not support universal thresholds or routine serial testing in all surgical patients. Biomarker kinetics should strengthen, but not replace, surgical reasoning or independently determine antimicrobial, imaging, or interventional decisions. Future research should validate setting-specific thresholds and sampling schedules, establish whether PCT provides actionable information before clinical deterioration, and evaluate the clinical effects and cost-effectiveness of PCT-informed pathways.

Antibiotics doi: 10.3390/antibiotics15101041

Authors: Md Sarower Hossen Shuvo Won Ju-young Sujin Jo Izaz Ahmed Md Tareque Aziz Ali Atashi Md Abu Raihan Park Yeji Cheong Hyunhee Taehyeon Kim Hyein Yu Haneol Bae Sukyung Kim Hoonhee Seo Ho-Yeon Song

Background: Hospital drainage systems represent an important interface between healthcare facilities and urban wastewater networks and may contribute distinct microbial inputs to downstream aquatic environments. This issue is particularly relevant in Seoul, Republic of Korea, where urban wastewater discharges into receiving waters within the Han River watershed. Methods: In this study, we characterized hospital drain microbiomes to evaluate their microbial and environmental signatures, using residential drains as a non-clinical comparison. Results: Hospital drains exhibited a distinct taxonomic profile, with greater relative abundances of Bacteroidota and Firmicutes and several genera of environmental or potential public health relevance, including Mycobacterium, Legionella, and Pseudomonas. Although microbial richness was comparable between the two environments, Simpson diversity was significantly lower in hospital drains, indicating reduced community evenness. Bray–Curtis and Jaccard analyses showed clear separation between hospital and residential microbial communities, and hierarchical clustering further supported environment-associated community structuring. LEfSe analysis identified distinct hospital-associated taxonomic biomarkers, and predicted functional profiling revealed substantial metabolic differentiation, with 19 of the 25 most significantly differentiated pathways enriched in hospital samples. Conclusions: These microbial and functional differences underscore the ecological uniqueness of hospital drains and support their inclusion in future wastewater-based microbial surveillance strategies. Collectively, these findings establish hospital drains as distinct microbial ecosystems within urban wastewater networks and provide a baseline for future studies examining the persistence of hospital-associated microbial signatures within the Han River watershed.

Antibiotics doi: 10.3390/antibiotics15101039

Authors: Hakim Ennaciri Amin Regragui Driss Bengoumi Naoufal Rahmatallah Rabii El Bahraouy Mohammed Sbiti Mohamed Reda El Rhaffouli Ikhlass El Berbri Hicham El Rhaffouli Ouafaa Fassi Fihri

Background/Objectives: Antimicrobial resistance (AMR) is a major One Health challenge affecting both human and animal health. Comparative studies investigating resistance patterns across reservoirs remain limited in Morocco. This study compared antimicrobial resistance profiles and presumptive β-lactam resistance phenotypes of extraintestinal Escherichia coli isolates from humans and broiler chickens. Methods: A comparative cross-sectional study was conducted using 874 non-duplicate human-derived E. coli isolates and 142 broiler-derived E. coli isolates. Antimicrobial susceptibility testing was performed using the disk diffusion method according to CA-SFM/EUCAST 2024 guidelines. Resistance rates and presumptive β-lactam resistance phenotypes were compared between reservoirs. Results: Broiler isolates exhibited significantly higher resistance to amoxicillin (93.0% vs. 65.5%), ticarcillin (92.9% vs. 64.1%), amoxicillin–clavulanic acid (75.2% vs. 48.1%), fluoroquinolones, trimethoprim–sulfamethoxazole, fosfomycin, and gentamicin (all p < 0.05). In contrast, resistance to cephalosporins was significantly higher among human isolates, whereas resistance to cefoxitin and carbapenems was detected exclusively among human isolates. The presumptive IRT-like phenotype was markedly more prevalent in broiler isolates (66.9% vs. 26.9%; OR = 5.50; p < 0.001), while the presumptive AmpC and carbapenem-resistant phenotypes were identified only in human isolates. Conversely, the wild-type phenotype was significantly more frequent among human isolates (33.1% vs. 5.6%; OR = 0.12; p < 0.001). The prevalence of the presumptive ESBL phenotype was comparable between reservoirs (12.1% vs. 8.5%; p = 0.258). Conclusions: Human-derived and broiler-derived E. coli isolates exhibited distinct antimicrobial resistance patterns and β-lactam resistance profiles. Resistance levels were significantly higher among broiler isolates for most antimicrobial agents tested, whereas resistance to cephalosporins was significantly higher among human isolates, with cefoxitin and carbapenem resistance detected exclusively in the latter. Human isolates displayed a greater diversity of presumptive β-lactam resistance phenotypes, whereas broiler isolates were largely dominated by the presumptive IRT-like phenotype. The detection of isolates with a presumptive ESBL phenotype among broilers despite the absence of documented routine use of extended-spectrum cephalosporins highlights the potential contribution of horizontal gene transfer and co-selection. Further molecular and antimicrobial consumption studies are warranted to clarify the drivers of resistance dissemination within a One Health framework.

Antibiotics doi: 10.3390/antibiotics15101040

Authors: Thérèsse C. N. Holmström Luana O. Silva Sophia M. P. O. Costa Leticia B. Pinto Mário T. Makita Cláudio M. Rocha-de-Souza Shana de M. O. Coelho Dayanne A. de Melo Irene S. Coelho Miliane M. S. de Souza

Background/Objectives: The Acinetobacter baumannii–calcoaceticus (Acb) complex comprises opportunistic pathogens of increasing relevance in human and veterinary medicine due to their capacity to acquire multidrug resistance. colistin, a last-resort antimicrobial for carbapenem-resistant A. baumannii (CRAB), is increasingly challenged by the emergence of resistance determinants, including those encoded by the mobilized colistin resistance (mcr) gene family. This study aimed to screen for mcr genes in Acb complex isolates recovered from animal and environmental sources in Rio de Janeiro State, Brazil. Methods: Thirty-five isolates obtained from dogs, cats, horses, and soil between 2018 and 2020 were genotypically identified using multiplex PCR. Of these, 23 successfully recovered isolates were screened for mcr variants (mcr-1 to mcr-9) by multiplex PCR. Results: Five isolates (21.7%) yielded amplicons of expected sizes consistent with the presence of mcr-associated determinants, including two consistent with mcr-7, one with mcr-8, and two with mcr-9. Because amplicon sequencing and phenotypic colistin susceptibility testing were not performed, these findings should be interpreted as preliminary molecular screening results. Conclusions: These findings indicate the presence of PCR-detectable mcr-associated genetic targets in isolates from animal and environmental sources, highlighting the need for further molecular characterization and integrated surveillance under a One Health framework.

Antibiotics doi: 10.3390/antibiotics15101038

Authors: Alice Caneschi Donatella Scarafile Monica Modesto Maurizio Scozzoli Paola Mattarelli Anna Zaghini

Background: The inflammation of the mammary gland, known as bovine mastitis, is a major challenge for the dairy cattle industry globally. The main organisms responsible for mastitis are bacteria, classified as either contagious, such as Staphylococcus aureus, Streptococcus dysgalactiae, and Streptococcus agalactiae, or environmental, primarily Streptococcus spp. (e.g., Streptococcus uberis) and coliform species. Even though the emergence of antibiotic-resistant strains of pathogens poses a serious threat, antibiotics are still the primary treatment for mastitis. It is therefore necessary to explore alternative therapies, such as essential oils (EOs). This in vitro research intended to evaluate the efficacy of EOs against pathogens associated with bovine mastitis, as an alternative or complementary treatment to conventional antibiotics. Methods: The bactericidal activity of eleven essential oils and two blends was tested on five strains related to bovine mastitis: S. agalactiae, S. dysgalactiae, S. uberis, S. aureus, and Staphylococcus epidermidis. An assessment was carried out of both the reduction of biofilm formation and the inhibition of pre-formed biofilm against biofilm-formative strains of S. aureus and S. epidermidis. Results: Origanum vulgare and Cinnamomum verum resulted to be the EOs with the highest activity against the above-mentioned bacteria, inhibiting both bacterial growth and biofilm formation. Conclusions: This study emphasizes the relevance of investigating natural products and supports the hypothesis of appropriate use of EOs to reduce bacterial infections and provide an effective alternative to antibiotics in complementary therapy. Moreover, to avoid treatment failure, the combined use of available antibiotics and natural compounds should also be considered.

Antibiotics doi: 10.3390/antibiotics15101037

Authors: Damaris Krul Alana Araújo Braga Danieli Conte Letícia Kappel Ferreira Libera Maria Dalla-Costa Lorena Bavia

Antimicrobial resistance (AMR) is a global public health challenge with remarkable impacts on human, animal, and environmental health within the One Health framework. Among the pathogens most frequently associated with healthcare-associated infections are bacteria belonging to the ESKAPEE group, which comprises Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp., and Escherichia coli. These microorganisms are the main cause of severe infections and difficult-to-treat infections due to multidrug resistance phenotypes driven by complex molecular mechanisms, including enzymatic inactivation, target-site modification, permeability alterations, and biofilm formation. Through a One Health lens, this narrative review synthesizes current evidence on ESKAPEE microorganisms, bridging environmental reservoirs (such as wastewater) with clinical resistance mechanisms, their relevance in hospital settings, and therapeutic strategies. This review highlights the relationship between AMR in ESKAPEE bacteria and the One Health approach, emphasizing the need for integrated strategies to mitigate the spread of resistant pathogens across human, animal, and environmental interfaces.

Antibiotics doi: 10.3390/antibiotics15101036

Authors: M. Mar Morcillo Serrano Paloma Reche-Sainz Daniel González-Reguero Marina Robas-Mora Rocío de la Iglesia Natalia Úbeda Elena Alonso-Aperte Javier Arranz-Herrero Pedro A. Jiménez-Gómez

In the published article [...]

Antibiotics doi: 10.3390/antibiotics15101035

Authors: Majd Alsoubani Maureen Campion Somya Swarup Pamela Lee Abarna Pearl Kap Sum Foong

Background: Antimicrobial administration is a major contributor to healthcare-associated waste. We evaluated the environmental impact of changing the default metronidazole dosing frequency from three-times-daily (TID) to twice-daily (BID) administration in a three-hospital system. Methods: We conducted a quasi-experimental uncontrolled interrupted time-series study across an integrated health system. Inpatient oral and intravenous metronidazole utilization was assessed from January 2023 through December 2024, before and after a change in the default metronidazole dosing on 1 February 2024. Overall utilization was measured as days of therapy (DOT)/1000 days present (DP), and frequency-specific utilization was standardized as dispensed doses/1000 DP. Plastic waste was estimated using EcoRxChoice, and modeled disposal-related carbon dioxide-equivalent (CO2e) emissions reflected facility-specific incineration and transportation processes. Results: Overall metronidazole utilization remained similar (36.4 pre-intervention vs. 37.2 DOT/1000 DP post-intervention). After implementation TID utilization decreased relative to baseline (−4.41 dispensed doses/1000 DP per month; 95% CI, −6.02 to −2.80 p < 0.001), whereas twice-daily utilization increased (+1.32 dispensed doses/1000 DP per month; 95% CI, 0.37 to 2.27 p = 0.007). Mean modeled plastic waste decreased from approximately 200 to 164 kg/month. Over the 11-month post-intervention period, the monthly trend decreased by 14.63 kg/month relative to the pre-intervention trend (95% CI, −21.42 to −7.83; p < 0.001) and modeled disposal-related 351.3 kg of CO2e. Conclusions: Optimizing antibiotic dosing frequency is a simple, scalable antimicrobial stewardship strategy that was associated with reductions in modeled metronidazole plastic waste and modeled disposal-related emissions while leveraging the established clinical non-inferiority of twice-daily metronidazole dosing.

Antibiotics doi: 10.3390/antibiotics15101034

Authors: Nicola Benvenuto Massimiliano Lanzafame Sergio Venturini Verena Zerbato Arianna Perosa Giovanni Mori Giovanni Del Fabro Tommaso Cai Chiara Zanusso Filippo Giorgio Di Girolamo Stefano Colla Valentina Gerussi Vasiliki Koumaki Marina Busetti Stefano Di Bella

Background: Temocillin is a narrow-spectrum β-lactam with activity against extended-spectrum β-lactamase (ESBL)- and AmpC-producing Enterobacterales and represents a potential carbapenem-sparing option, especially for urinary tract infections (UTIs). This multicentre study evaluated the real-world use, clinical outcomes, and tolerability of temocillin in Italian clinical practice. Methods: We retrospectively included adults treated with temocillin for UTIs, with or without concomitant bloodstream infection, for at least 5 days at three Italian hospitals between November 2024 and May 2026. Data were collected from electronic medical records. Results: The study included 30 patients. Median age was 51 years (IQR 39–74); 50% presented with sepsis and 40% had UTI-associated bacteraemia. Pyelonephritis was the most common presentation (53.3%). At least one positive culture was obtained in 76.7% of patients, yielding 28 isolates. Of these, 27 were Enterobacterales, and 21/27 (77.8%) were ESBL producers. E. coli accounted for 64.3% of all isolates. Temocillin was administered at 6 g/day in 80% of patients and by continuous infusion in 76.7%. Outpatient parenteral antimicrobial therapy (OPAT) using elastomeric pumps was used in 16.7% of patients. Clinical success at the end of the overall antimicrobial treatment course was achieved in 28/30 patients (93.3%; 95% CI 77.9–99.2%). No recurrence occurred within 30 days, and no treatment-related adverse events directly attributable to temocillin were recorded. Two patients developed Clostridioides difficile infection within 60 days after treatment completion, with no established causal relationship with temocillin. Conclusions: This first Italian multicentre real-world experience reports favourable clinical outcomes with temocillin in UTIs, including in selected patients with sepsis or UTI-associated bloodstream infection, and describes the use of continuous infusion and OPAT in appropriately selected patients.

Antibiotics doi: 10.3390/antibiotics15101033

Authors: Jayasinghage Nirmani Chathurnagika Jayasinghe Chamilani Nikapitiya Vijaya R. Dirisala Tae-Won Kim Mahanama De Zoysa Ilson Whang

Background/Objectives: The genus Shigella is one of the major pathological agents responsible for diarrhea and diarrhea-related mortality worldwide. It shows a decreasing sensitivity to most conventional antibiotics available today. Methods: Hence, an antimicrobial peptide, Octominin II, was conjugated to a cell-penetrating peptide (HIV-TAT) named TAT-Octominin II, and its antibacterial effect against Shigella flexneri was investigated. Results: TAT-Octominin II displayed minimum inhibitory and bactericidal concentrations of 10 and 25 µg/mL, respectively. It showed rapid membrane-permeabilizing activity, as observed in the ONPG assay. TAT-Octominin II treatment altered the cell membrane integrity and causing membrane damage in S. flexneri. Moreover, TAT-Octominin II increased oxidative stress, as evidenced by the upregulation of antioxidant genes, such as sodA, sodB, katG, oxyR, and soxR. Furthermore, TAT-Octominin II bound to genomic DNA and RNA, which likely inhibited the transcription and translation of bacterial proteins. In addition, TAT-Octominin II possessed lipopolysaccharide neutralization activity. In vitro toxicity analysis was performed using mammalian Raw 264.7 and HEK 293 cells, which showed no toxicity at lower concentrations (0–100 µg/mL). Conclusions: Overall, our results demonstrate that TAT-conjugated Octominin II exhibits enhanced antibacterial activity compared to Octominin II alone, suggesting that TAT-mediated delivery of AMPs could be a promising strategy to improve the therapeutic efficacy of AMPs.

Antibiotics doi: 10.3390/antibiotics15101032

Authors: Ali H. Farsi Moaz W. Abulfaraj Ghazal Y. Dhaher Roaa M. Gaid Mimoona K. Ayfan Mariya I. Alrefaei Mohammed F. Alhazmi Murad M. Aljiffry

Background/Objectives: Surgical site infection (SSI) after surgery for inflammatory bowel disease (IBD) has not been described microbiologically in the Arabian Peninsula, where extended-spectrum beta-lactamase (ESBL) prevalence is high and prophylaxis remains largely cephalosporin-based. We described the microbiology of SSI after IBD surgery and the extent to which recovered microorganisms were expected to be covered by the prophylaxis administered. Methods: We retrospectively studied consecutive gastrointestinal operations for IBD at a tertiary center in Jeddah, Saudi Arabia (April 2014 to November 2025). Of 118 eligible operations, 8 performed through a dirty/infected wound were reported separately, leaving a primary cohort of 110 operations in 91 patients. The primary outcome was deep incisional or organ/space SSI by CDC/NHSN criteria; models used cluster-robust standard errors for repeated operations. The microbiological analysis was exploratory. Results: SSI followed 33 of 110 operations (30.0%; 95% CI 22.2–39.1), of which 22 (66.7%) were deep or organ/space. Cultures were positive in 23 of 33 infections; because specimens were obtained at clinician discretion, microbiological estimates apply to this subset only. An acquired resistance phenotype was recorded in 10 of 23 (43.5%): ESBL-producing Enterobacterales in 8 and methicillin-resistant Staphylococcus aureus in 2. All operations received prophylaxis within 60 min of incision, but five regimens were in use. Expected non-coverage of at least one isolate, assigned from recorded phenotype and intrinsic resistance, was present in 7 of 11 culture-positive infections after cephalosporin-based prophylaxis (63.6%; 95% CI 35.4–84.8) and 0 of 12 after broader-spectrum regimens, with 5 indeterminate. Low preoperative serum albumin and absence of IBD-directed therapy were associated with deep infection after adjustment; emergent surgery was not, although it was in a sensitivity analysis that included the dirty/infected operations. Conclusions: These findings describe prophylaxis–spectrum discordance and support microbiological surveillance and locally informed review of prophylaxis policy rather than empirical broadening.

Antibiotics doi: 10.3390/antibiotics15101031

Authors: Elife Çapan Gün Şeyma Şimşirgil Kara Yasemin Akın

Background/Objectives: We evaluated changes in antibiotic resistance among urine culture isolates from children under five years hospitalized with urinary tract infection (UTI) at a single center in 2019–2020 and 2024–2025. Methods: This retrospective, repeated cross-sectional study included 498 children and analyzed 359 isolates of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Proteus spp. As second-line agents were tested selectively, primary outcomes (defined post hoc) were resistance to a core panel of agents tested in at least 90% of isolates and core-panel multidrug resistance (MDR) in Enterobacterales; other comparisons were exploratory. Fisher’s exact test, Benjamini–Hochberg correction, and adjusted Firth regression were used. Results: Second-line agents were tested mainly in cefuroxime-resistant isolates (95% vs. 7% for ceftazidime in E. coli), biasing resistance estimates. In the core panel, no difference was significant in E. coli, and the decrease in cefuroxime resistance in K. pneumoniae did not survive correction. Core-panel MDR was lower in 2024–2025 (51.9% vs. 38.7%; p = 0.019; adjusted OR 0.56, 95% CI 0.35–0.88); full-category MDR was not (68.4% vs. 58.3%; p = 0.067). Conclusions: Differences may reflect testing practices and case mix rather than true changes in resistance. Findings apply only to hospitalized children under five years at this center and require confirmation.

Antibiotics doi: 10.3390/antibiotics15101030

Authors: Dominik Zawadzki Natalia Libergal Mikołaj Kisiała Hanna Gwoździk Oskar Ratajczyk Mateusz Hejnowicz Piotr Misiąg Łukasz Nowak Dawid Janczak Wojciech Krajewski Tomasz Szydełko Bartosz Małkiewicz

Background: It is estimated that approximately 20–30% of women suffer from recurrent urinary tract infections (rUTIs). The disease is primarily bacterial, especially Escherichia coli, making antibiotics the standard treatment. Increasing antibiotic resistance of uropathogens reduces treatment effectiveness. Therefore, non-antibiotic approaches are increasingly being investigated for the management of rUTIs. This narrative review provides a comprehensive overview of currently available and emerging methods of treatment and prevention of rUTIs in women. Methods: This paper employs a narrative review with a structured literature search and synthesizes data from three major databases, including PubMed, Web of Science, and Scopus. The review was conducted in accordance with the Scale for the Assessment of Narrative Review Articles (SANRA) checklist. Scientific articles were searched using the following keywords: ‘recurrent urinary tract infections in women’, ‘antibiotic prophylaxis’, ‘immunoprophylaxis’, ‘urinary microbiome’. Results: Observational evidence has reported an association between continuous antibiotic prophylaxis and severe outcomes, including pyelonephritis and septicemia; however, these findings are susceptible to confounding by indication and should not be interpreted as evidence of a causal relationship. Clinical studies suggest that immunomodulatory approaches, such as OM-89 bacterial lysate, next-generation polybacterial mucosal vaccines (e.g., MV140), and oral immunostimulants, have potential to reduce the frequency of rUTI recurrences in women, although the strength and certainty of evidence vary between interventions. Bacteriophage therapy is an emerging and exploratory targeted approach supported by early clinical and experimental evidence, but its efficacy for preventing recurrent uncomplicated UTIs remains uncertain, though rapid development of phage resistance remains a potential limitation. Prophylactic strategies, including Lactobacillus-based probiotics, low-dose estriol, and microbiota transplantation, have shown preliminary or variable results, with limited evidence for rUTI prevention. In particular, findings on vaginal dysbiosis and microbiota modulation should not be interpreted as a direct evidence of rUTI prevention. Conclusions: While antibiotic therapy remains essential, continuous prophylaxis may contribute to antimicrobial resistance and disrupt microbial balance. Therefore, novel therapeutic strategies are still being studied. Several non-antibiotic strategies, including immunoprophylaxis and microbiome modulation, represent potential preventive approaches, whereas bacteriophage therapy and vaginal microbiota transplantation remain exploratory and require further clinical validation. Their preventive efficacy against rUTIs remains unestablished. Moreover, antimicrobial peptides (AMPs), nanotechnology, molecularly targeted therapies, and precision medicine strategies are being investigated. Plant-based therapies may provide benefit, but their clinical efficacy remains to be established. Overall, further clinical studies are needed to confirm the preventive efficacy of these emerging approaches.

Antibiotics doi: 10.3390/antibiotics15101029

Authors: Nailya A. Zigangirova Dmitry Yu. Pushkar Nataliya E. Bondareva Nadezda L. Lubenec Tamara S. Perepanova Elena A. Smolyarchuk Vladimir B. Beloborodov Andrey V. Zaycev Sergey K. Zyryanov Maria A. Kareva Evgenia U. Levchenko Anna B. Sheremet Alexander L. Gintzburg

Background/Objectives: New data on the pathogenesis of recurrent urinary tract infections (rUTIs) and the growing level of bacterial resistance to antibiotics require a revision of patient treatment strategies and a search for non-antibiotic approaches to the treatment and prevention of UTIs. The aim of this study was to investigate the clinical and microbiological efficacy of a new, non-traditional antibacterial drug, Fluorothiazinone (FT). Methods: We conducted an open-label, randomized, multicenter cohort clinical trial, phase III, at 12 hospitals in Moscow and St. Petersburg. A total of 280 patients were randomized into two groups in a 1:1 ratio to receive FT at a dose of 1200 mg/day for 14 days or furadonin at a dose of 400 mg/day for 7 days. Clinical and microbiological cures were assessed 7, 14, and 28 days after the start of therapy. Results: For the primary efficacy endpoint, clinical cure at day 28, the recovery rate was 91.7% in patients receiving FT and 92.8% in patients receiving furadonin, the hypothesis of non-inferiority of FT compared to the standard furadonin regimen was confirmed by two-sided 95% confidence intervals. The proportion of patients with clinical cure on days 7 and 14 also did not differ in the two groups. An assessment of microbiological eradication at all observation times in our study demonstrated that FT, whose mechanism of action is associated with the suppression of pathogen virulence, possesses antibacterial activity comparable to that of the antibiotic furadonin, leading to the eradication of pathogens causing rUTIs. The frequency of microbiological relapses after 28 days of treatment was 19.6% in the group receiving FT and 22.2% in the group receiving furadonin. Both study groups were comparable in the severity of adverse events (AEs). A definite relationship with the study drugs was identified for 1 (11.1%) AE after taking FT and 8 (88.9%) AEs after taking furadonin. Conclusions: Clinical trials in patients with recurrent cystitis have demonstrated the intrinsic antibacterial activity of FT, equal clinical and microbiological efficacy compared to first-line drugs for the treatment of recurrent cystitis, as well as a high level of safety, indicating the potential for the use of drugs with a new mechanism of action in the context of growing antibiotic resistance.

Antibiotics doi: 10.3390/antibiotics15101028

Authors: Abel Compbel Chipembo Martin Henderson Kalumbi Aminata Kamara Naserah Fatmata Koroma Marie Louise Iragena Kumbukani Chikosa Mary Maimu Goliath Eneya Zulu Precious Innocent Mastala Sam Mvula Thomas Malinki Rejoice Msiska Alberto Pondja Janelisa Musaya Belisário Moiane Niura Madalena Bila

Background: Antibiotic resistance is becoming a serious problem in chicken production globally due to the use of antibiotics. In Mzimba, the multiple antibiotic resistance index (MARI) pattern in chicken meat is not known and has not been documented. Objective: To assess the prevalence of antibiotic-resistant Escherichia coli, Salmonella, and Enterobacter species in broiler chicken meat sold in informal markets in Mzimba District, Malawi, using the MAR index. Materials and Method: A cross-sectional study was conducted between March and May 2025. A total of 100 meat samples were collected from the informal markets across the district. A stratified sampling technique was used to select chicken meat samples from various markets. Descriptive statistics and inferential statistics were performed using R version 4.5.3. Results: E. coli (69%) and Enterobacter (12%) species were the most frequently isolated pathogens. The highest prevalence of antibiotic resistance was observed in E. coli against ampicillin (91%), meropenem (83%), and tetracycline (71%). Similarly, Enterobacter spp. showed substantial resistance to tetracycline (83%), ampicillin (83%) and meropenem (75%). The MAR index values were considerably high, ranging from 0.1 to 0.75. A total of 97.1%, 91.7% and 100% of the positive isolates of E. coli, Enterobacter and Salmonella spp., respectively, had MAR index values over 0.2. Location was the most significant predictor of the MAR index (p = 6.096 × 10−5, η2 = 0.372). Conclusions and Recommendations: High levels of the MAR index were revealed in this study. As such, combating MDR requires coordinated multisectoral approaches through One Health programs that integrate surveillance, policies, and innovation to prevent and control antimicrobial resistance.

Antibiotics doi: 10.3390/antibiotics15101027

Authors: Alexandra Bucătaru Andrei Osman Ovidiu Mircea Zlatian Eugen Mihail Arnautu Andrei Theodor Bălășoiu Maria Bălășoiu Georgiana Cristiana Camen Alex Ioan Salan Andreea-Loredana Golli Alice Elena Ghenea

Background/Objectives: Rapid molecular detection of antimicrobial resistance determinants has the potential to optimize antimicrobial therapy before conventional antimicrobial susceptibility testing becomes available. However, the clinical utility of these assays depends on the concordance between detected resistance genes and phenotypic susceptibility. This study aimed to evaluate the genotype–phenotype concordance of carbapenemase and β-lactamase genes detected by the Unyvero multiplex-PCR platform with minimum inhibitory concentration (MIC)-based susceptibility profiles obtained using the phenotypic AST comparator method in Gram-negative clinical isolates. Methods: A total of 117 non-duplicate Gram-negative clinical isolates recovered from hospitalized patients at a Romanian tertiary-care hospital were analyzed. Resistance determinants, including blaKPC, blaOXA-48, blaOXA-23, blaCTX-M, blaTEM, together with aminoglycoside, fluoroquinolone, and sulfonamide resistance markers, were identified using the Unyvero multiplex-PCR system. Phenotypic antimicrobial susceptibility testing was performed using the VITEK®2 automated system according to EUCAST criteria. Genotype–phenotype concordance was evaluated using sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and Cohen’s κ coefficient. Results: Overall, 78.8% (78/99) of isolates were classified as non-susceptible. blaOXA-48 was the most frequently detected carbapenemase gene (n = 12), followed by blaKPC (n = 9) and blaOXA-23 (n = 3). blaKPC demonstrated a sensitivity of 100% for predicting imipenem resistance in Enterobacterales, with moderate agreement (κ = 0.58), whereas blaOXA-23 showed complete diagnostic performance (100% sensitivity and PPV) for carbapenem resistance in Acinetobacter baumannii. In contrast, all blaOXA-48-positive Enterobacterales remained phenotypically susceptible to carbapenems, indicating poor genotype–phenotype concordance. Likewise, blaCTX-M, gyrA83/87, and qnrA/B/S showed limited diagnostic performance for corresponding phenotypic resistance. Conclusions: Phenotype–genotype concordance varies across resistance determinants and Gram-negative bacterial species. Detection of blaKPC and blaOXA-23 may support early optimization of antimicrobial therapy, whereas blaOXA-48 should be interpreted together with conventional phenotypic antimicrobial susceptibility testing. Integrating rapid molecular diagnostics with phenotypic susceptibility testing may improve antimicrobial stewardship and optimize the management of multidrug-resistant Gram-negative infections.

Antibiotics doi: 10.3390/antibiotics15101026

Authors: Anna Maria Spagnolo Maria Teresa Montagna Osvalda De Giglio

Antimicrobial resistance (AMR) represents a severe problem in public health due to the increasing spread amongst the general population, animals, and the environment of antibiotic-resistant microorganisms with resistance phenotypes extended to more than one class of antibiotics [...]

Antibiotics doi: 10.3390/antibiotics15101025

Authors: Jeslin Cheruvathoor Jenny Andrzej S. Skwarecki Michał K. Pierański Katarzyna Kozłowska-Tylingo Piotr Szweda

Objectives: Chrysin and pinocembrin are two key flavonoids contributing to the antimicrobial activity of poplar propolis. However, their antimicrobial potency when used independently is limited. In this study, amino acid (AA)- and triphenylphosphonium (TPP)-based derivatives of chrysin and pinocembrin were designed, synthesised, and evaluated for their antimicrobial activity, with particular focus on their antifungal potential and mechanism of action. Methods: AA- and TPP-based derivatives of chrysin and pinocembrin were synthesised and characterised. Their antimicrobial activity was evaluated against selected bacterial and fungal strains. The mechanism of antifungal activity of the most active compounds was further investigated. Additionally, their haemolytic activity was also evaluated. Results and Conclusions: TPP derivatives, compounds 11 and 12, showed substantially enhanced antimicrobial activity against Candida albicans, Candida glabrata, Candida krusei, Staphylococcus aureus, and Escherichia coli. Further investigation indicated that compounds 11 and 12 are capable of inducing membrane depolarisation while exhibiting negligible haemolytic activity. These findings support TPP-based derivatisation as a promising approach for improving the antimicrobial potential of these propolis-derived flavonoids.

Antibiotics doi: 10.3390/antibiotics15101024

Authors: Laura Sophie Schmidt Henri Tong Lilli Freund Vincent-Christoph Klaus Christoph Lübbert Amrei von Braun Henning Trawinski Klaus H. Metzeler Marco Herling Uta Ceglarek Thilo Bertsche Yvonne Remane

Background: Vancomycin therapy is challenging in hematology patients due to their complex therapies, frequent infections, variable renal function, and nephrotoxic co-medications, resulting in high pharmacokinetic variability. Methods: Vancomycin therapy was retrospectively analyzed over three consecutive periods using routine clinical data from a German tertiary academic hematology ward, focusing on recommended loading dose administration, therapeutic trough concentration attainment (15–20 mg/L), and a potential acute kidney injury (AKI): (I) baseline cohort (BC)—usual care; (IIa) infectious diseases support cohort (IDSC)—following collaboration with infectiologists; and (IIb) infectious diseases and pharmacy support cohort (IDPSC)—following additional clinical pharmacist involvement. Results: Overall, 155 patients receiving 164 vancomycin cycles were included. Recommended loading dose adherence increased from 3.3% (n = 3/90) in the BC to 32.6% (n = 15/46) in the IDSC and 53.6% (n = 15/28) in the IDPSC. The difference was statistically significant for both IDSC and IDPSC vs. BC (χ2 test, p < 0.001). Across cohorts, therapeutic trough concentrations were attained faster with the recommended than with an inadequate loading dose (median 4 vs. 8 days; log-rank test, p = 0.001). Subtherapeutic trough levels decreased (BC 78.6% vs. IDSC 65.5% vs. IDPSC 46.4%), while supratherapeutic levels increased (BC 7.6% vs. IDSC 10.8% vs. IDPSC 23.2%), accompanied by a higher AKI incidence (BC 20.0% vs. IDSC 17.4% vs. IDPSC 39.3%). The difference in AKI was statistically significant for IDPSC vs. BC (χ2 test, p = 0.038) and IDSC (χ2 test, p = 0.037). Conclusions: A recommended vancomycin loading dose within the interprofessional care cohort achieves therapeutic trough concentrations faster but requires close monitoring for nephrotoxicity.

Antibiotics doi: 10.3390/antibiotics15101022

Authors: Anita Seres-Steinbach Péter Szabó Ágnes Solti-Hodován Viktória Lilla Balázs Krisztián Bányai György Schneider

Background/Objectives: The presence of extended-spectrum β-lactamase-producing Escherichia coli (ESBL-producing E. coli) is a major global concern as it causes hard-to-treat infections that can sometimes be life-threatening. Methods: Using the drop plate method, we examined which essential oils (EOs) were effective against the tested strains. After mapping the general biofilm-forming affinity of the isolates, we attempted to degrade the biofilm using the EOs. Results: Certain EOs can kill ESBL-producing E. coli, inhibit biofilm formation, and degrade mature biofilms. The drop plate method showed that 50 (83%) and 54 (90%) of the 60 tested EOs were effective against 20 different human and porcine ESBL-producing E. coli isolates when applied at 1% and 5%, respectively. The most effective ESBL-producing E. coli isolate (23R20) was used for anti-biofilm testing. The temperature of 37 °C was most effective in inhibiting and degrading biofilms, although this was markedly influenced by the carrier medium. Ajowan, cinnamon, oregano, and thyme had outstanding effects in both tests, inhibiting and degrading biofilms by 99%, respectively. Morphological differences (e.g., deformation, elongation or shortening of cells, amorphous structures, and ‘ghost’/perforated cells) were noted in the 23R20 E. coli cells exposed to ajowan, cinnamon, oregano, and thyme. Conclusions: Ajowan, cinnamon, oregano, and thyme were the most effective biofilm-degrading and -inhibitory EOs.

Antibiotics doi: 10.3390/antibiotics15101023

Authors: Md. Ekramul Karim Taryn Eubank Khurshida Begum M. Jahangir Alam Julian G. Hurdle Kevin W. Garey

Background/Objectives: Biofilm formation is a major bacterial survival strategy in response to antibiotic stress. The bacterial second messenger cyclic di-GMP (c-di-GMP) is a central regulator of biofilm development. Sub-minimum inhibitory concentrations (sub-MICs) of antibiotics act as biological active environmental cues that reprogram bacterial physiology and promote biofilm development. This systematic review synthesizes the current literature on sub-MIC antibiotic-induced biofilm formation across different pathogenic bacterial genera and critically evaluates the role of c-di-GMP. Methods: A systematic literature search was conducted in PubMed and Scopus for articles published from inception to 18 December 2025 using terms including “sub-MIC antibiotic” AND (“biofilm” OR “antibiotic-induced biofilm”) and a second search using “sub-MIC antibiotic” AND “biofilm” AND “c-di-GMP”. Reviews, commentaries, opinions, meta-analyses, systematic reviews, and non-English-language articles were excluded. Results: Collectively, 28 identified studies demonstrate that sub-MIC antibiotics modulate biofilm formation through diverse mechanisms that intersect with c-di-GMP activity, including modulation of diguanylate cyclases and phosphodiesterases and through regulatory networks that intersect with quorum sensing and different two-component systems. These responses influence multiple components of biofilm matrix- and biofilm-associated physiology, including exopolysaccharides, extracellular DNA, cell surface proteins, secretion systems, and stress-adaptive multicellular behavior. Conclusions: By positioning c-di-GMP as an integrative, but context-dependent, signaling hub linking antibiotic-induced stress, metabolic adaptation, persistence, and biofilm development, this review highlights critical mechanistic gaps and identifies potential therapeutic targets for disrupting biofilms and improving antibiotic efficacy.

Antibiotics doi: 10.3390/antibiotics15101021

Authors: Tania Vlad Daliborca Cristina Vlad Calin Muntean Corina Flangea Victor Dumitrașcu Roxana Popescu Mihai Mitulețu Cristian Sebastian Vlad

Background: Real-world outcome data on Clostridioides difficile infection (CDI) from Eastern Europe are scarce, and partly digitised hospital records make surveillance laborious. We characterised the epidemiology, comorbidity, treatment and in-hospital mortality of CDI in a Romanian tertiary hospital and validated a rule-based pipeline for extracting surveillance variables from free-text records. Methods: Retrospective two-period cohort (1 September 2023 to 31 December 2025) of 295 CDI episodes at the Pius Brinzeu County Emergency Clinical Hospital, Timisoara. Thirty variables were extracted from narrative records with a lexical algorithm applied identically to both periods and validated against manual coding (n = 144). Mortality predictors were analysed by logistic regression with LASSO selection, bootstrap-corrected discrimination and calibration testing. Results: Mean age was 69.2 years. Hypertension (76.6%), heart failure (46.4%), neoplasm (39.3%), ascites or pleural effusion (61.7%), sepsis (56.9%) and pneumonia (44.4%) were common; vancomycin was documented in 83.7% of episodes and non-CDI antibiotics in 85.8%. In-hospital mortality during the index admission was 33.6%. Sepsis (adjusted OR 2.68), pneumonia (2.53) and ascites or pleural effusion (2.32) independently predicted death (optimism-corrected AUC 0.75), whereas individual chronic comorbidities lost significance after adjustment; mortality rose from 6.8% with none of the three acute markers to 61.1% with all three. Toxin index magnitude was unrelated to death. The second period had a higher comorbidity score (3.1 vs. 2.5, p = 0.002). Extraction reached at least 90% accuracy for 15 of 22 variables (median kappa 0.89). Conclusions: Acute organ involvement, much more than underlying comorbidity, determines in-hospital CDI mortality in this setting. Rule-based extraction supports reproducible CDI surveillance in partially digitised hospitals when low-agreement variables are verified by hand.

Antibiotics doi: 10.3390/antibiotics15101020

Authors: Fitim Bexhet Alidema Arieta Hasani Alidema Njomza Lajçi Berisha

Background: Distinguishing bacterial from non-bacterial infections remains challenging in pediatric practice. This study evaluated the relationship between inflammatory biomarkers, microbiological evidence, and antibiotic prescribing, with particular emphasis on agreement between treatment decisions and a study-specific bacterial evidence classification. Methods: This retrospective observational study included 2688 pediatric patients evaluated between January 2023 and March 2026. A nonvalidated, study-specific Bacterial Evidence Score (BES; 0–6 points) combined fever, C-reactive protein, white blood cell count, absolute neutrophil count, procalcitonin, and positive bacterial culture. The primary outcome was disagreement between antibiotic prescribing and the study-defined BES threshold (≥2), rather than independently confirmed inappropriate prescribing. Multivariable logistic regression was used to evaluate factors associated with antibiotic prescribing and BES-based decision disagreement. Results: Antibiotics were prescribed to 1974 patients (73.4%), of whom 1391 (70.5%) received agents classified as broad-spectrum. Microbiological testing was performed in 913 patients (34.0%), yielding 362 positive cultures. Antibiotic prescribing increased overall across BES levels, from 36.9% at score 0 to 98.1% at score 6 (adjusted odds ratio per point, 1.28; 95% confidence interval, 1.17–1.41). Under the study-specific BES ≥ 2 classification, 825 decisions (30.7%) disagreed with the scoring rule; this proportion does not represent the prevalence of clinically inappropriate prescribing. Among culture-positive patients, 167 (46.1%) received pathogen-directed antibiotic therapy supported by microbiological findings, and 91 (25.1%) underwent microbiology-guided treatment modification. Clinical resolution or improvement was documented in 2224 patients (82.7%). Conclusions: Antibiotic prescribing was associated with cumulative inflammatory and microbiological evidence. However, the BES-based classification was exploratory and sensitive to the selected threshold, while microbiological findings were not necessarily available at initial prescribing. These findings support further evaluation of integrated diagnostic and antimicrobial stewardship approaches, with prospective validation required before clinical application.

Antibiotics doi: 10.3390/antibiotics15101019

Authors: Yasemin Ay Altıntop Ekin Kırbaş Banu Sancak

Background/Objectives: Colistin remains a last-resort therapy for carbapenem-resistant Klebsiella pneumoniae bloodstream infections, yet its accurate reporting depends on the reference broth microdilution (BMD) method that few clinical laboratories routinely deploy. We aimed to determine the prevalence of colistin resistance in bloodstream isolates and to quantify the diagnostic performance of the widely used VITEK 2 Compact automated system in a Turkish tertiary-care hospital. Methods: We prospectively analysed 253 consecutive non-duplicate blood culture isolates (144 K. pneumoniae; 109 Escherichia coli) obtained at a Turkish tertiary-care hospital between July 2022 and March 2023. Paired colistin susceptibility testing used BMD (EUCAST guidance, polypropylene plates, no surfactant) and VITEK 2 Compact with AST-N326 cards. EUCAST v12.0 breakpoints (susceptible ≤ 2 mg/L; resistant > 2 mg/L) were applied. Very major error (vME) rate was benchmarked against the ISO 20776-2 acceptance threshold of 3%. Results: BMD identified colistin resistance in 22.5% (95% CI 17.8–28.1) of isolates, with a striking inter-species disparity: 38.2% for K. pneumoniae versus 1.8% for E. coli (Fisher exact p = 1.1 × 10−13; OR 33.1, 95% CI 8.0–138). VITEK 2 misclassified 32 of 57 truly resistant isolates as susceptible; under the ISO 20776-2 denominator the very major error rate was 56.1% (32/57; 95% CI 43.3–68.3), approximately 18-fold above the ISO acceptance threshold of 3% (p < 0.0001). Overall sensitivity for colistin resistance detection was 43.9% (25/57); for K. pneumoniae alone, sensitivity was 45.5% (25/55) and specificity 95.5% (85/89), and every skipped-well BMD isolate (n = 11) was reported susceptible by VITEK 2. Conclusions: Automated colistin testing underdetects resistant K. pneumoniae bloodstream isolates in a high-prevalence setting. Our findings support continued adherence to BMD as the reference standard for colistin susceptibility in such settings, with automated systems used for screening and complemented by reference-method confirmation of critical isolates.

Antibiotics doi: 10.3390/antibiotics15101018

Authors: Beatriz de Souza Cardoso Mônica Campos dos Santos Mariana Rodrigues Trápaga Cecília Bittencourt Severo Jéssica Estefania Dávila Hidalgo Gilson Zeni Cristina Wayne Nogueira David A. Stevens Melissa Orzechowski Xavier Vanice Rodrigues Poester

Background/Objectives: Dermatophytosis is among the most prevalent fungal infections worldwide, and the emergence of antifungal resistance highlights the need for novel the-rapeutic strategies. Organoselenium compounds have demonstrated promising antifungal activity against several pathogenic fungi, although their activity against dermatophytes remains poorly explored. Here we investigate the in vitro antifungal activity of four organoselenium compounds, ebselen, diphenyl diselenide [(PhSe)2], p-methoxy-diphenyl diselenide (BMD), and bis-(3-trifluoromethyl phenyl) diselenide (CF3). Methods: Eighteen clinical isolates belonging to the T. mentagrophytes (n = 10) and T. rubrum (n = 8) species complexes were studied and potential synergism with fluconazole (FCZ) also explored. Antifungal susceptibility testing and drug interaction were performed according to Clinical and Laboratory Standards Institute broth microdilution protocols and checkerboard assay, respectively. Results: Ebselen, (PhSe)2, and BMD inhibited all Trichophyton spp. isolates with a geometric mean (GM) of minimum inhibitory concentration (MIC) less than or equal to 6 µg/mL. CF3 inhibited 78% (14/18) of the isolates and had higher MICs (GM ≥ 43.5 µg/mL). Combination assays revealed synergistic interactions between FCZ and the organoselenium compounds, ranging from 45% to 89%, without antagonistic interactions. Moreover, FCZ activity was enhanced in 57–86% of resistant isolates, with BMD showing the most favorable profile in combination with FCZ. Conclusions: These findings demonstrate the promising antifungal potential of organoselenium compounds against the major dermatophytes associated with human infection and support further investigation of these compounds, particularly ebselen, (PhSe)2, and BMD, as novel antifungal agents, either alone or in combination with conventional antifungal drugs.

Antibiotics doi: 10.3390/antibiotics15101017

Authors: Yousef Al-Hajaya Shadi Mustafa Ma’en Al-Odat Amane Alaroud Enas Almanasreh Muna M. Abbas Yasmeen Hazaimeh Mais Hijazi Anwar Kandari

Background: Antimicrobial resistance (AMR) is one of the most significant current public health issues, which is driven crucially by the misuse and overuse of antibiotics. Antibiotics are still available without a prescription in many underdeveloped countries, including Jordan, allowing for self-medication and incorrect usage, which contributes to the establishment and spread of resistant bacteria. This cross-sectional study aimed to evaluate antibiotic-use practices and assess knowledge and awareness of antimicrobial resistance among the Jordanian population. Methods: We conducted a cross-sectional observational survey between September 2023 and January 2025, targeting males and females in Jordan. A QR code was used to distribute an online convenience sampling strategy with 57 questions across social media channels. The survey investigated a variety of aspects, including demographic traits, antibiotic knowledge and behaviour, and public awareness of resistance. The questionnaire was completed by 1031 people. The data was analysed using descriptive statistics. The chi-square test was performed to compare demographic groupings, and p < 0.05 was considered significant. Results: Among the 1031 participants, 61.3% were female and 37.8% were male. Recent utilization of antibiotics was prevalent, with 37.8% indicating usage in the preceding month and 26.4% within the last six months. It is noteworthy that 61% (n = 624) of participants indicated that they had consumed antibiotics without a prescription, while 33.6% (n = 345) reported acquiring antibiotics for children without a prescription. Furthermore, pharmacies constituted the predominant source of antibiotics, accounting for 90.4% of the total. Common misconceptions regarding the indications for antibiotics were observed, with a segment of participants under the impression that antibiotics are effective in treating symptoms such as fever (40.6%) and body pain (15%). Additionally, participants exhibited a moderate level of awareness regarding antimicrobial resistance, with 69.2% demonstrating familiarity with the concept, while 90% acknowledged the increased difficulty in treating infections caused by antimicrobial-resistant organisms. Nevertheless, major misconceptions persisted, including 84.8% incorrectly believing that antibiotic resistance occurs when the human body becomes resistant to antibiotics and then antibiotics cannot work properly. More than half of the respondents (n = 569; 57.1%) also believed that AMR only or mainly affects individuals who frequently take antibiotics and does not concern others. Conclusions: This study has identified that non-prescription antibiotic use remains prevalent in Jordan and is accompanied by substantial misconceptions regarding antimicrobial resistance. Although general awareness of the seriousness of AMR was relatively high, important knowledge gaps persisted. In the adjusted analysis, among the covariates, participants aged 51–60 years had higher odds of reporting non-prescription antibiotic use than those aged 18–30 years (aOR = 1.872, 95% CI 1.072–3.268; p = 0.028). Moreover, participants with a high-school education (aOR = 0.415, 95% CI 0.196–0.879; p = 0.022) and those with a master’s degree (aOR = 0.411, 95% CI 0.181–0.933; p = 0.034) had lower odds than the no-formal-education reference group. No other covariate was statistically significant. The findings clearly indicate the need for strengthened enforcement of prescription-only antibiotic dispensing regulations, targeted public education to address specific misconceptions, and expanded antimicrobial stewardship initiatives involving community pharmacists to promote responsible antibiotic use and lessen the growing threat of antimicrobial resistance.

Antibiotics doi: 10.3390/antibiotics15101016

Authors: Blaž Cugmas Eva Štruc Urška Vesel Daira Viškere Liisi Kulasalu Dulmini Nanayakkara Sapugahawatte

Background/Objectives: Rapid antimicrobial decision-making in small-animal practice is limited by the turnaround time (≥2 days) of conventional laboratory-based culture and antimicrobial susceptibility testing (AST). Existing point-of-care and in-clinic tests can provide faster results, but their performance often depends on user experience. This study evaluated VetBac, a hybrid workflow in which the test is conducted in the clinic, while experts centrally interpret bacterial growth on plates. Methods: We analyzed 60 interpretable plates from canine and feline skin, ear, and urine infections. In the clinic, samples were inoculated onto chromogenic Mueller–Hinton agar plates, after which antibiotic discs were applied. Plates were incubated for 16–20 h, photographed, and interpreted centrally by an expert. For comparison, samples were submitted in parallel to standard microbiology laboratories. Results: Identification of primary bacterial populations in clinical samples showed high species-level agreement with laboratory results (83.9%), increasing to 100.0% when staphylococci species were grouped. Secondary bacteria agreement (16.7%) was lower due to unrecognizability and overgrowth by dominant bacteria. Overall AST agreement was 93.6% (262/280), with 91.9% sensitivity for detecting resistance and 94.0% specificity for detecting susceptibility. VetBac-susceptible discrepancies occurred in 5/62 laboratory-resistant comparisons (8.1%), and VetBac-resistant discrepancies occurred in 13/218 laboratory-susceptible comparisons (6.0%). Conclusions: In interpretable skin, ear, and urine samples, the VetBac workflow showed high agreement with laboratory results for primary bacterial identification and AST. These findings support the hybrid in-clinic/centralized model as an adjunctive source of earlier antimicrobial decision support, pending laboratory confirmation. However, the study did not estimate the proportion of all clinical samples suitable for direct culture and AST.

Antibiotics doi: 10.3390/antibiotics15101015

Authors: Audrey Lanyan Nicolas Fourré Virgile Zimmermann Laurence Senn Benoit Guery Matthaios Papadimitriou-Olivgeris

Background/Objectives: Catheter-related bloodstream infections (CRBSIs) may lead to metastatic complications. However, risk factors for such complications remain insufficiently characterized. This study aims to identify risk factors associated with metastatic infectious complications in patients with CRBSI. Methods: This monocentric cohort study included adult patients with CRBSI due to Gram-positive cocci or Candida spp. (2015–2024). The primary endpoint was the occurrence of metastatic complications, including infective endocarditis, embolic events, bone and joint infections, and vascular graft infections. Results: A total of 1023 CRBSI episodes were included. Staphylococcus aureus was the most common pathogen (331 episodes; 32%), followed by coagulase-negative staphylococci (307; 30%), enterococci (175; 17%), Candida spp. (171; 17%), and streptococci (98; 10%). Metastatic complications occurred in 93 episodes (9%). In multivariable logistic regression, female sex (aOR 1.61; 95% CI 1.02–2.56), S. aureus infection (aOR 1.62; 95% CI 1.01–2.61), community-onset infection (aOR 2.23; 95% CI 1.26–3.95), septic deep vein thrombosis (aOR 2.19; 95% CI 1.04–4.58), and persistent bacteremia ≥ 48 h (aOR 4.54; 95% CI 2.78–7.44) were independently associated with metastatic complications. In the S. aureus subgroup, only persistent bacteremia remained significant (aOR 6.28; 95% 3.12–12.6). Conclusions: Metastatic complications occurred in approximately 9% of CRBSI episodes but were strongly associated with persistent bacteremia, particularly in S. aureus infections. Persistence of bloodstream infection and community-onset presentation should prompt evaluation for metastatic foci.

Antibiotics doi: 10.3390/antibiotics15101014

Authors: Jessica Alves dos Santos Adriana Bozzi Marianna Gabrielle Almeida Galvão Aline Silva

Background/Objectives: The global rise in antimicrobial resistance has intensified the search for alternative therapeutic strategies capable of overcoming bacterial tolerance and biofilm-associated infections. Iron oxide nanoparticles (IONPs) have emerged as promising candidates due to their physicochemical properties and potential multimodal mechanisms of action. This integrative review aimed to evaluate the antibacterial and antibiofilm activity of iron oxide nanoparticles against Gram-positive and Gram-negative bacteria, as well as their potential synergistic effects with conventional antibiotics. Methods: A structured search was conducted in PubMed, Web of Science, BVS, LILACS, and Redalyc databases using predefined descriptors related to iron nanoparticles and bacterial inhibition. Fifteen studies published between 2014 and 2024 met the inclusion criteria. The methodological quality of the included studies was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist. Most studies presented low to moderate risk of bias and the findings were categorized into three thematic areas: antibacterial activity of IONPs, synergistic interaction with antibiotics, and reported adverse effects. Results: Overall, IONPs demonstrated inhibitory effects against clinically relevant pathogens, including Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, showing activity against both planktonic cells and biofilm formation. Synergistic effects with antibiotics were frequently reported, suggesting enhanced antimicrobial efficacy potentially mediated by increased membrane permeability and reactive oxygen species generation. Conclusions: Iron oxide nanoparticles show promising antibacterial and antibiofilm effects and may act as adjuncts to conventional antibiotics. Nevertheless, further standardized and translational studies are required before clinical implementation.

Antibiotics doi: 10.3390/antibiotics15101013

Authors: Lina I. Alnajjar Taif A. Alahmari Shahad A. Almutairi Rawan A. Alniwaider Mercy Joseph Abdullah K. Alruwaili Alaa A. Alhubaishi Ahlam Alghamdi Anwar M. Alnakhli Abdulrahman S. Alissa Amani A. Bahdailah Mohammed A. Alraey Isra Z. Farooqi Asem A. Allam Reem Binsuwaidan

Background: Carbapenem-resistant Enterobacteriaceae (CRE) prevalence has been increasing in Saudi Arabia, posing a significant public health concern. Antimicrobial stewardship programs (ASPs) play an important role in reducing resistance by ensuring appropriate antibiotic use. Our study aimed to assess the appropriateness of meropenem prescriptions pre-ASP and post-ASP implementation in the Intensive Care Unit (ICU) ward. Method: This is a retrospective quasi-experimental pre–post study conducted over 3 years, from 2020 to 2023 at King Abdullah bin Abdulaziz University Hospital (KAAUH). The study included adult ICU patients who received meropenem therapy. The primary objective was to evaluate the appropriateness of meropenem prescriptions in the ICU before and after ASP implementation. The secondary objectives were to identify reasons for inappropriate prescribing and evaluate the interventions implemented to address inappropriate meropenem use. Result: A total of 113 patients were included: 34 in 2020, 41 in 2022, and 38 in 2023. Appropriate meropenem prescribing increased significantly from 23.5% in 2020 to 26.8% in 2022 and 57.9% in 2023 (p = 0.003), while inappropriate prescribing decreased from 76.5% to 73.2% and 42.1%, respectively. Treatment duration also differed significantly across study periods (p = 0.002), with courses of 7–10 days increasing from 24.2% in 2020 to 53.7% in 2022 and 52.6% in 2023, while courses exceeding 10 days decreased from 51.5% to 12.2% and 18.4%, respectively. Among inappropriate prescriptions, an inappropriate antimicrobial spectrum was the predominant reason (81.9%), with no inappropriate dosing identified. Documented stewardship interventions differed significantly across periods (p < 0.001): de-escalation increased from 0% in 2020 to 43.3% in 2022 and 50.0% in 2023, while prescriptions completed without documented intervention decreased from 69.2% to 23.3% and 18.8%, respectively. Conclusion: ASP implementation was associated with a significant improvement in the appropriateness of meropenem prescribing and a shift toward shorter treatment durations among adult ICU patients. Nevertheless, inappropriate prescribing remained substantial in the second post-implementation year, emphasizing the need for continued antimicrobial stewardship interventions and ongoing monitoring of carbapenem use.

Antibiotics doi: 10.3390/antibiotics15101011

Authors: Carina Sofia Silva Matias Klaus Skovbo Jensen Henrik Hasman Kasper Thystrup Karstensen Bjørg Bolstad Bjørn Klem Pål Rongved Carina Vingsbo Lundberg Jon Ulf Hansen

Background: Carbapenem-resistant Enterobacterales (CRE) represent a major therapeutic challenge, driven in part by serine β-lactamases (SBLs) and metallo-β-lactamases (MBLs). APC24-7 is a broad-spectrum β-lactamase inhibitor (BLI) designed to inhibit enzymes from both groups. Here, we evaluated the ability of APC24-7 to potentiate meropenem (MEM) activity against meropenem-resistant Escherichia coli and Klebsiella pneumoniae. Methods & Results: Checkerboard assays were performed against 31 K. pneumoniae and 17 E. coli isolates harboring a range of clinically relevant SBL and/or MBL genes. APC24-7 reduced meropenem minimum inhibitory concentrations (MICs) in an isolate- and concentration-dependent manner. At 32 mg/L APC24-7, meropenem MICs fell within the CLSI susceptible range for meropenem in 11 of 17 E. coli isolates, whereas 16 of 31 K. pneumoniae isolates remained resistant. Time-kill experiments with nine selected isolates showed bactericidal activity under active combination conditions, defined as a ≥3 log10 CFU/mL reduction from the initial bacterial count, within 3–5 h. Pharmacokinetic evaluation in infected mice showed less-than-dose-proportional systemic exposure following subcutaneous administration of APC24-7, with a maximum plasma concentration of approximately 26 mg/L after a 30 mg/kg dose. In a neutropenic murine thigh infection model, APC24-7 increased meropenem activity against four selected in vitro-responsive isolates in a dose-dependent manner. Conclusions: These findings provide preclinical proof of concept for APC24-7 as a broad-spectrum BLI capable of potentiating meropenem against Enterobacterales harboring diverse β-lactamases, while highlighting substantial isolate-dependent variability that warrants further pharmacokinetic/pharmacodynamic and resistance-mechanism studies.

Antibiotics doi: 10.3390/antibiotics15101012

Authors: Biagio Santella Antonio Donato Vittoria Satriani Laura Grumiro Stefano Stracquadanio Emanuela Santoro Luigi Fortino Claudia Colosimo Alice Nicolosi Maddalena Calvo Graziella Manciagli Zirone Nunziata Agata Silvana Trifilò Maria Giuseppina Pecora Giuseppe Arcoleo Monica Cricca Stefania Stefani Vittorio Sambri Giovanni Boccia

Background: Environmental contamination of hospital surfaces, especially in high-risk clinical areas, partly sustains healthcare-associated infections. The detection of microbiological contamination in hospital settings using culture-based methods remains fundamental, even though these methods are not rapid, show moderate sensitivity in areas with low microbial loads, and are unsuitable for some microbial species. This multicentre study evaluated the performance of loop-mediated isothermal amplification (LAMP) for the rapid detection of major nosocomial pathogens on hospital surfaces. Methods: A multicentre observational method–comparison study was conducted in three Italian hospital centres. Overall, 298 environmental surface samples were collected from clinical areas included in local infection-prevention monitoring plans. For each sampling point, LAMP swab sampling was paired with an adjacent contact plate culture. LAMP assays targeted Staphylococcus aureus, Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Manual and automated nucleic acid extraction workflows were analysed separately. Diagnostic performance, agreement metrics, and discordant paired results were assessed using a contact plate culture as the microbiological comparator. Results: No LAMP-negative/RODAC-positive pairs were observed. Positive percent agreement (PPA) relative to contact plate culture was therefore 100% in the subgroups evaluated. Relative specificity ranged from 90.9% to 98.6%, while overall accuracy ranged from 93.8% to 98.6%. Discordant results were exclusively LAMP-positive/contact plate-negative and were more frequent for S. aureus and P. aeruginosa. Selective culture verification supported several LAMP-positive findings not recovered by routine contact plates. Conclusions: LAMP showed high negative agreement, high specificity, and rapid target-specific detection of selected nosocomial pathogens on hospital surfaces. It may complement conventional cultures in environmental surveillance, particularly when timely feedback is needed to guide infection-prevention and sanitation-monitoring strategies.

Antibiotics doi: 10.3390/antibiotics15101010

Authors: Lucía Requena-Fernández Noemí Camacho-Blanco Antonio Rosales-Castillo Leticia Castellano-Sánchez José Gutiérrez-Fernández

Background: Metallo-β-lactamase (MBL)-producing Gram-negative bacteria represent one of the greatest therapeutic challenges in contemporary clinical microbiology because of their extensive antimicrobial resistance and the limited availability of effective treatment options. Aztreonam–avibactam and cefiderocol have emerged as promising therapeutic alternatives; however, comparative evidence from routine clinical practice remains limited. Methods: A systematic literature search was conducted in PubMed to identify studies published between 2015 and 2025 evaluating the in vitro activity of aztreonam–avibactam and cefiderocol against MBL-producing Gram-negative bacteria. A total of 22 fully accessible studies meeting the eligibility criteria were included and analyzed in the systematic review. In parallel, a retrospective cross-sectional study was performed including all urinary isolates producing MBL recovered at the Microbiology Laboratory of Virgen de las Nieves University Hospital (Granada, Spain) between January 2016 and December 2025. Antimicrobial susceptibility profiles for both novel agents and conventional antibiotics were analyzed. Results: Twenty-three studies met the inclusion criteria for the systematic review, of which 22 fully accessible articles were analyzed. In the systematic review, Enterobacterales accounted for 70.0% of the reported MBL isolates, with New Delhi metallo-β-lactamase (NDM) being the predominant enzyme globally (50.5%), followed by Verona integron-encoded metallo-β-lactamase (VIM) (39.4%). The crude aggregated in vitro susceptibility proportion across the literature was markedly higher for aztreonam–avibactam than for cefiderocol (93.1% vs. 58.1%). Conversely, in our local urinary cohort (n = 182), Enterobacterales were also the predominant pathogens (51.6%), but VIM was the most frequently detected carbapenemase (n = 107). In this local cohort, aztreonam–avibactam demonstrated 100% in vitro susceptibility against Enterobacterales (54/54) and exhibited a 77.8% wild-type (WT) phenotype against Pseudomonas spp. (35/45). Cefiderocol exhibited excellent activity against Pseudomonas spp. (86.2%, 50/58) but significantly lower susceptibility rates among Enterobacterales (39.6%, 21/53). Among conventional antimicrobials, in vitro susceptibility in Enterobacterales to gentamicin decreased significantly over time (from 62.5% to 32.8%; FDR-adjusted p = 0.029), whereas amikacin in vitro susceptibility significantly improved (from 60.0% to 88.1%; FDR-adjusted p = 0.048). Colistin maintained high susceptibility rates, ranging from 87.8% to 100% in Enterobacterales and 77.8% to 88.2% in Pseudomonas spp. Agents such as nitrofurantoin (restricted exclusively to Escherichia coli) and trimethoprim–sulfamethoxazole or fosfomycin were not evaluated for Pseudomonas spp., due to intrinsic resistance or absence of established EUCAST clinical breakpoints. Conclusions: Aztreonam–avibactam and cefiderocol exhibit promising but highly species-specific in vitro activity against MBL-producing Gram-negative bacteria. While colistin and amikacin remain active conventional in vitro alternatives, these laboratory findings represent potential microbiological potency rather than guaranteed clinical success. Prospective clinical trials and real-world outcome studies remain essential to evaluate the clinical efficacy, patient outcomes, and comparative in vivo effectiveness of these regimens in daily practice.

Antibiotics doi: 10.3390/antibiotics15101009

Authors: Septimiu Voidazan Réka Bodea Liviu Moraru Iuliu Moldovan Daniela Iancu Mihaela Alexandra Budianu

Background: Healthcare-associated infections (HAIs), particularly those caused by antimicrobial-resistant pathogens, remain an important cause of adverse outcomes among hospitalized patients. The combined contribution of antimicrobial resistance, clinical characteristics, and antimicrobial treatment to mortality requires further evaluation. This study aimed to investigate factors associated with in-hospital mortality among patients with HAIs, with particular emphasis on multidrug resistance (MDR) and post-culture antimicrobial treatment. Methods: We conducted a retrospective observational cohort study that included 192 patients with 242 documented HAI episodes in a hospital in Târgu-Mureș, Romania. Demographic and clinical characteristics, invasive procedures, microbiological findings, antimicrobial resistance phenotypes, antimicrobial exposure, and in-hospital outcome were evaluated. Comparisons between survivors and non-survivors were performed using the Mann–Whitney U test, Pearson’s chi-square test, or Fisher’s exact test, as appropriate. Factors associated with in-hospital mortality were investigated using univariable and multivariable logistic regression. Results: Overall, 161/192 patients (83.9%) died during hospitalization. Non-survivors were significantly older than survivors [median: 71 (IQR: 62–78) vs. 62 (50.5–72) years; p = 0.025]. MDR organisms were more common among non-survivors (51.6% vs. 22.6%; p = 0.003), and MDR phenotype was associated with increased odds of mortality in univariable analysis (OR = 3.65, 95% CI: 1.49–8.95; p = 0.005). After adjustment for age, mechanical ventilation, and recent surgery, MDR remained independently associated with in-hospital mortality (aOR = 3.58, 95% CI: 1.42–8.98; p = 0.007). In the treatment-focused model, aminopenicillin exposure (aOR = 0.21, 95% CI: 0.07–0.64; p = 0.006), second-generation aminoglycosides (aOR = 0.23, 95% CI: 0.06–0.97; p = 0.045), and third-generation cephalosporins (aOR = 0.35, 95% CI: 0.14–0.88; p = 0.025) were associated with lower odds of mortality. No significant association was observed between time to specific antimicrobial therapy and mortality (p = 0.541). Conclusions: MDR was the main antimicrobial-resistance factor independently associated with in-hospital mortality among patients with HAIs. Although several antimicrobial classes were associated with lower odds of death, these observational associations should not be interpreted as causal treatment effects. The findings emphasize the importance of antimicrobial resistance surveillance, rapid microbiological diagnosis, antimicrobial stewardship, and timely access to active antimicrobial therapy.

Antibiotics doi: 10.3390/antibiotics15101008

Authors: Shaguneet Kour Neelesh Sharma Natesan Balaji Sandeep Kour Ankit Magotra Young-Ok Son

Background/Objectives: Bovine mastitis is a major economic and health challenge in the dairy industry, heavily dependent on antibiotics and increasingly complicated by antimicrobial resistance (AMR). This study evaluated the in vitro therapeutic efficacy of trans-4-hydroxycinnamic acid (4-HCA) as a novel alternative therapeutic agent on bovine mammary epithelial cells (bMECs). Specifically, the objectives were to assess the biofilm-forming capacity of mastitis-associated bacterial isolates, determine the antibacterial and bactericidal profile of 4-HCA, and investigate its immunomodulatory effects on infected bMECs using quantitative real-time PCR (qRT-PCR). Methods: A panel of fourteen bovine mastitis-origin bacterial isolates was evaluated for biofilm production using both the tube method and the microtiter plate assay. The antibacterial activity of 4-HCA was determined via agar well diffusion, disc diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) assays. Cytotoxicity and safe working concentrations of 4-HCA on bMECs were established using the MTT cell-viability assay (3.125 to 800 µg/mL). Furthermore, an in vitro inflammatory model using bMECs infected separately with Staphylococcus aureus and Escherichia coli (1 × 106 CFU/mL) was treated with 4-HCA (50 and 100 µg/mL) or ciprofloxacin. Relative transcriptional expression profiles of pro-inflammatory cytokines (IL-1, IL-6, and TNF- α) were quantified via qRT-PCR and analyzed using the comparative 2−ΔΔCT method. Results: Quantitative biofilm evaluations identified 19% to 22% of the bacterial isolates as strong biofilm producers and 25% to 31% as moderate producers, with prominent biofilm formation observed in Enterococcus faecalis, Raoultella planticola, Shigella sonnei, and Staphylococcus aureus. 4-HCA exhibited robust bactericidal efficacy with mean MIC values ranging from 0.625 to 1.25 mg/mL and MBC values from 2.5 to 10 mg/mL. The MTT assay confirmed 100% bMEC viability at the experimental treatment concentrations of 50 and 100 µg/mL. qRT-PCR analyses revealed that 4-HCA treatment significantly modulated (p < 0.05) pro-inflammatory cytokine transcript profiles. In the S. aureus model, treatment significantly downregulated TNF-alpha expression while differentially upregulating IL-1 and IL-6 mRNA levels, demonstrating cytokine-specific immunomodulation. Conversely, in the E. coli model, 4-HCA induced a concentration-dependent reduction across all evaluated pro-inflammatory cytokines (IL-1, IL-6, and TNF- α). Conclusions: Trans-4-hydroxycinnamic acid demonstrates significant in vitro antibacterial activity, biofilm disruption potential, and targeted immunomodulatory effects on bovine mammary epithelial cells. These findings establish a strong foundational basis for exploring 4-HCA as a promising alternative therapeutic agent for managing bovine mastitis and mitigating antimicrobial resistance in veterinary medicine.

Antibiotics doi: 10.3390/antibiotics15101007

Authors: Kwang Mi Kim Su Hyeon An Ju Won Kim Ye Bin Park Seonjeong Kim Sujeong Kim Young Ho Byun Sera Moon Yo Han Jang

Background/Objectives: Green tea-derived catechins, including epigallocatechin gallate (EGCG), possess diverse antimicrobial properties. This study investigated the dual antiviral and antibacterial activities of a commercially available green tea extract (cGTE) preparation and EGCG against influenza viruses and representative oral bacteria to evaluate their potential for oral and upper respiratory applications. Methods: The antiviral activities of the cGTE preparation and EGCG against influenza A virus strains H1N1 (A/Puerto Rico/8/1934) and H5N2 (mouse-adapted influenza A/aquatic bird/Korea/w81/2005) were evaluated by assessing virucidal activity, time-of-addition experiments, and inhibition of hemagglutinin (HA) and neuraminidase (NA) activities. Antibacterial activity was assessed following direct exposure of Gram-positive oral streptococci (Streptococcus mutans, S. salivarius, S. mitis, S. sanguinis, and S. sobrinus), Staphylococcus aureus, and Gram-negative Escherichia coli strains to the cGTE preparation or EGCG. Results: Both the cGTE preparation and EGCG exhibited concentration- and time-dependent virucidal activities against A/H1N1 and A/H5N2 viruses. Direct treatment of the viruses generally produced greater antiviral effects than cell pre- or post-treatment. Both treatments also inhibited HA and NA activities, suggesting that interference with viral surface-associated functions may contribute to their antiviral effects. In addition, the cGTE preparation and EGCG reduced bacterial viability following direct exposure, with EGCG showing strong direct antibacterial activity against oral Streptococcus species. Conclusions: The cGTE preparation and EGCG exhibited dual virucidal and direct antibacterial activities against influenza viruses and a range of oral bacteria. These findings support their potential as multifunctional antimicrobial agents for locally applied formulations targeting the oral and upper respiratory environments.

Antibiotics doi: 10.3390/antibiotics15101006

Authors: Sohyeong Kim Heechul Park Minju Jung Soyun Kim Jieun Lim Choseung Kim Sangha Kim Jinyoung Bae Jiyoung Lee Min Park Sunghyun Kim

Background: Fluoroquinolone resistance in methicillin-resistant Staphylococcus aureus (MRSA) involves multiple mechanisms, including quinolone resistance-determining region (QRDR) mutations and efflux pump activity. However, the relationship between these resistance mechanisms and virulence factors (VFs) remains unclear. This study investigated the relative contributions of QRDR mutations and carbonyl cyanide 3-chlorophenylhydrazone (CCCP)-responsive mechanisms to fluoroquinolone resistance in MRSA and their associations with VF profiles. Methods: Sixty ciprofloxacin-resistant MRSA bloodstream isolates were analyzed. The minimum inhibitory concentrations (MICs) of ciprofloxacin (CIP) and levofloxacin (LEV) were determined before and after treatment with the efflux pump inhibitor CCCP. The isolates were classified as CCCP responsive or non-responsive based on a ≥4-fold reduction in CIP MICs. The associations of QRDR mutations in gyrA, gyrB, parC, and parE and virulence-associated genes with CCCP responsiveness were evaluated. Results: CCCP significantly reduced both CIP and LEV MICs, although changes in LEV MICs were limited to a subset of isolates. Of the 60 isolates, 15 were CCCP responsive, whereas 45 were non-responsive. The non-responsive isolates had significantly more QRDR mutations, particularly gyrA nucleotide mutations and GyrA amino acid substitutions. fnbA-positive isolates showed greater CCCP-mediated CIP MIC reductions and fewer QRDR nucleotide mutations, whereas seg-, sei-, and tst-positive isolates showed lower CCCP-mediated CIP MIC reductions and greater QRDR nucleotide mutation numbers. Conclusions: QRDR mutations and CCCP-responsive mechanisms were differentially associated with fluoroquinolone resistance phenotypes in MRSA. Their associations with distinct VF profiles suggest a potential relationship between CCCP responsiveness, QRDR mutation profiles, and the virulence genetic background of MRSA.

Antibiotics doi: 10.3390/antibiotics15101005

Authors: Jesús García-Gómez Mauricio Alfredo Ambriz-Alarcón Brian Rafael Rubio-Mora Luis Felipe Jave-Suárez Adriana Aguilar-Lemarroy María Martha Villaseñor-García Georgina Hernández-Flores María Concepción Rodríguez-Lora Teresita De Jesús Hernández-Flores Liliana Iñiguez-Gutiérrez Luis Eduardo del Moral-Trinidad Anibal Samael Méndez-Clemente

Background/Objectives: Whether the COVID-19 pandemic uniformly increased antimicrobial resistance (AMR) is contested, and aggregate analyses may mask organism-specific patterns. The objective of the study was to characterize changes in the level and slope of monthly multidrug-resistant (MDR), possible extensively drug-resistant (pXDR), possible pandrug-resistant (pPDR), vancomycin-resistant enterococci (VRE), and methicillin-resistant Staphylococcus aureus (MRSA) positivity at a Mexican tertiary-care hospital, and to assess heterogeneity by organism, antimicrobial class, specimen type, and hospital service. Methods: Retrospective interrupted time-series of deduplicated bacterial isolates (October 2017 to January 2026), analyzed by segmented regression across pre-pandemic, pandemic, and post-peak phases. Results: Cohort-wide MDR positivity had been declining before 2020 and rose abruptly at pandemic onset (level shift +6.81 percentage points, p = 0.0092) with a simultaneous slope reversal, reaching 24.27 percentage points above the extrapolated pre-pandemic trend by February 2022 (95% CI 14.26–34.28, p < 0.0001). The decline resumed after the pandemic peak, but the two slope changes did not offset one another (joint p = 0.0064). pXDR and pPDR moved in the same direction (+8.93, p = 0.0233; +15.40, p = 0.0113). VRE showed no significant departure, whereas MRSA declined in every phase yet departed significantly from its extrapolated trajectory (+23.68, p = 0.0040). Among species, Escherichia coli showed the largest departure from its counterfactual (+48.82 percentage points, p < 0.0001) and Klebsiella pneumoniae had the largest abrupt level rise (+14.46 percentage points, p = 0.0055), while S. aureus declined in every phase despite an abrupt rise in level at pandemic onset. At the class level, carbapenem and third-/fourth-generation cephalosporin non-susceptibility rose at pandemic onset and returned to baseline afterwards (19.1% to 28.0% to 18.7%, and 51.7% to 59.4% to 52.5%; all q < 0.001), whereas fluoroquinolone non-susceptibility rose and did not revert, climbing further in E. coli (61.5% to 65.2% to 72.7%, q = 0.0012) and plateauing at an elevated level in K. pneumoniae (37.6% to 46.5% to 49.3%, q = 0.1919 post-peak). Conclusions: Resistance trajectories across pandemic-related phases were divergent and, for the Gram-negative organisms, incompletely reversed, with the highest burden of advanced resistance in high-intensity settings. Organism-resolved surveillance and sustained stewardship are needed.

Antibiotics doi: 10.3390/antibiotics15101004

Authors: Parul Berry Vishwesh Bharadiya Sahil Khanna

Clostridioides difficile infection (CDI) remains a major cause of healthcare-associated diarrhea and is being increasingly recognized in community settings. The management of CDI is complicated by diagnostic uncertainty, recurrent disease, and uneven access to newer therapies. Clinicians must distinguish infection from colonization, individualize therapy selection, and anticipate barriers to recurrence prevention. This narrative review examines diagnostic and therapeutic barriers in adult CDI care, with particular emphasis on the U.S. healthcare, regulatory, and reimbursement setting. Several guidelines prefer fidaxomicin for an initial nonfulminant CDI episode when available. Oral vancomycin is an effective alternative, and metronidazole is reserved for initial nonsevere CDI when preferred agents are unavailable. Antibiotic options for recurrent CDI include standard or extended-pulsed fidaxomicin and standard-course or tapered-and-pulsed vancomycin regimens. After antibacterial treatment, conventional fecal microbiota transplantation (FMT) and two FDA-approved microbiota products, fecal microbiota spores, live-brpk (VOS) and fecal microbiota, live-jslm (RBL), may be used in appropriately selected patients to prevent another recurrence. In ECOSPOR III, recurrence through 8 weeks was 12.4% of VOS recipients and 39.8% of placebo recipients. In PUNCH CD3, Bayesian model–estimated treatment success through 8 weeks was 70.6% with RBL and 57.5% with placebo. Because the trials used different populations, endpoints, definitions, and analytical frameworks, these figures should not be interpreted as a head-to-head comparison. The discontinuation of bezlotoxumab in the United States and reduced availability of stool bank-derived FMT have further constrained recurrence prevention options. Practical considerations include diagnostic stewardship, assessment of recurrence risk, and timely access to indicated recurrence prevention therapy.

Antibiotics doi: 10.3390/antibiotics15101003

Authors: Răzvan Roșca Călin Muntean Mirela Frandeș Ruxandra Laza Daian-Ionel Popa Victor Bogdan Buciu Cătălin Prodan-Bărbulescu Mădălina-Ianca Șuba Sorina Maria Denisa Laitin

Background/Objectives: Romania reports among the highest rates of carbapenem-resistant Gram-negative bacteria in the European Union, but patient-level data on healthcare-associated infections (HAIs) are scarce. We characterised carbapenem resistance, in-hospital outcomes, and carbapenem prescribing in a 24-month HAI cohort. Methods: This was a retrospective study of 315 patients with microbiologically confirmed HAI (2024–2025) at a tertiary infectious diseases hospital, contributing 243 Gram-negative isolates. Carbapenem resistance was determined by the hospital laboratory; extensively drug-resistant (XDR) status, defined as susceptibility to no more than two of the antimicrobial classes tested, was assigned under the hospital surveillance protocol. Risk-factor analysis was exploratory. Results: Of 243 Gram-negative isolates, 162 (66.7%) were carbapenem-resistant and 150 of these (92.6%) were designated XDR. Resistance reached 90.6% in Klebsiella pneumoniae and 83.0% in Acinetobacter baumannii, against 33.3% in Pseudomonas aeruginosa and 0% in Escherichia coli, and occurred at every infection site. No routinely recorded characteristic distinguished resistant from susceptible infection after adjustment (area under the curve 0.62). In-hospital death was associated with intensive care transfer (adjusted odds ratio 6.92, 95% confidence interval 3.33–14.38) but not with carbapenem resistance (1.14, 0.52–2.50). Of 92 carbapenem recipients, 54 (58.7%) had a carbapenem-resistant isolate, against which carbapenems are inactive, and 12 (13.0%) had a Gram-negative isolate that was neither carbapenem-resistant nor extended-spectrum β-lactamase-producing. Conclusions: At this centre, carbapenem resistance in Gram-negative HAI is endemic, could not be predicted from the routinely recorded characteristics examined, and exceeds European surveillance figures only among the Enterobacterales. No independent association with mortality was detected, although the susceptible comparison group was small. The XDR proportion was assigned under the hospital surveillance protocol and is not directly comparable with category-based estimates. Because antibiotic exposure was recorded without timing relative to culture sampling, these data support prospective audit of carbapenem prescribing rather than demonstrating missed de-escalation.

Antibiotics doi: 10.3390/antibiotics15101002

Authors: Ádám Kerek Gergely Álmos Tornyos Edit Szarka Levente Hunor Husz Máté Hetyésy László Kovács Ákos Jerzsele

Background/Objectives: Regional antimicrobial-resistance surveillance can be strengthened by linking phenotypic susceptibility data with genomic evidence. We characterized chicken-associated commensal bacteria from Northern Hungary and examined resistance-gene evidence in available Escherichia coli assemblies. Methods: Broth-microdilution minimum inhibitory concentration (MIC) data were available for 166 bacterial isolates collected in 2022–2023. Among the 69 E. coli isolates in this collection, 24 had corresponding draft whole-genome assemblies, defined here as assembled contig sets that had not been resolved into closed genomes; these assemblies were linked to the MIC records of the same isolates. Analyses included MIC distributions, descriptive correlations, principal component analysis, assembly-quality assessment, resistance-gene profiling, and sequence-context analysis. Results: The collection comprised 26 Staphylococcus spp., 71 Enterococcus spp., and 69 E. coli isolates. In E. coli, ceftriaxone MIC50 and MIC90 values were 0.031 and 512 µg/mL, respectively. Five assemblies contained blaCTX-M-1-labelled intervals that were identical across 876 bp and corresponded to ceftriaxone MICs of 32–1024 µg/mL. In E. coli isolate 1316, seven resistance-gene calls co-occurred within a 12,933-bp region of one contig. Assembly quality varied substantially, and the draft assembly of E. coli isolate 832 was unsuitable for reliable gene-negative interpretation. Conclusions: The dataset showed heterogeneous susceptibility profiles and identifiable resistance-gene contexts. These findings support isolate-linked phenotypic and genomic surveillance while avoiding population-level, transmission, or clinical resistance classifications unsupported by the available data.

Antibiotics doi: 10.3390/antibiotics15101001

Authors: Gloria María Molina-Salinas Andrés Humberto Uc-Cachón

Plant-derived antimicrobial agents have gained increasing scientific attention as antimicrobial resistance continues to rise globally, reducing the effectiveness of conventional antibiotics and complicating the management of emerging and drug-resistant pathogens [...]

Antibiotics doi: 10.3390/antibiotics15101000

Authors: Chonticha Romyasamit Komwit Surachat Nawanwat C. Pattaranggoon Morteza Saki Phoomjai Sornsenee

Background: Palmyra palm sugar harbors lactic acid bacteria (LAB) with antimicrobial and probiotic properties. Lacticaseibacillus paracasei strains WU0904 and WU2302 inhibit methicillin-resistant Staphylococcus aureus (MRSA) and reduce biofilm formation. In this study, we aimed to characterize the distribution and architecture of bacteriocin-associated loci across L. paracasei. Methods: A screening set of 67 genomes was filtered at ≥95% average nucleotide identity (ANI) and dereplicated at ≥99.9% ANI, yielding 44 nonredundant L. paracasei genomes. Results: Pangenome analysis identified 7213 gene clusters, comprising 1848 core, 230 soft core, 1528 shell, and 3607 cloud clusters. AntiSMASH analysis identified two major bacteriocin-associated regions in each WU strain. The larger region contained a conserved multipeptide bacteriocin-associated locus comprising predicted prebacteriocins, class II bacteriocins, and genes associated with immunity, regulatory, processing, and export, whereas the smaller region contained a two-gene Blp-family locus. The nine-component backbone of the large locus was complete in 34/44 genomes (77.3%), whereas the small Blp-family locus was present in 18/44 genomes (40.9%). The 59-aa accessory candidate, group_2723, was restricted to WU2302, DmW_181, and CBA7104 and was identical in sequence and syntenic position across these genomes. Phylogenetic analyses showed significant clustering of the small Blp-family locus and group_2723, whereas the large-locus backbone was more broadly distributed. Structural prediction indicated predominantly α-helical conformations among the prioritized bacteriocin candidates. Conclusions: The study findings reveal a shared bacteriocin-associated biosynthetic architecture comprising a conserved backbone and lineage-restricted components, providing specific candidates for future functional validation.