Antibiotics

Background/Objectives: Implant-associated infections are challenging conditions in orthopedic surgery. This experimental study aimed to evaluate phage localization within infected tissues following different routes of administration. Methods: An implant-related infection model was created using methicillin-resistant Staphylococcus aureus (MRSA) in twenty-four rats. Subjects were randomly divided into four groups depending on the bacteriophage administration route. Three rats were designated as the control group. Phage suspension was applied intraperitoneally, intravenously, orally and locally at 0.1 mL/day of 1 × 10⁸ PFU/mL suspension for three consecutive days. In the control group, intravenous, intraperitoneal and oral phage suspensions were administered separately at the same dose for 3 days. After completion of the experiment, tibia samples were taken in the experimental group. Additionally, liver, kidney, stomach, brain, heart muscle and striated muscle tissue samples were taken from the three subjects in the control group. Results: In the control group, unconfirmed phage-like structures were incidentally observed in some mitochondria of renal proximal tubular epithelial cells on transmission electron microscopy. In the experimental group, there was a strong positive linear relationship between the total number of bacteria and the number of bacteriophage clusters, independent of the groups. Conclusions: Bacteriophage clusters were detected in infected tibial tissues after all administration routes, suggesting phage localization at the infection site. Unexpected phage-like clusters were observed within mitochondria of proximal tubular epithelial cells in the control animals. This finding should be regarded as an unconfirmed incidental finding requiring further validation. Full article

Background: Despite its typically self-limiting course, acute diarrheal disease continues to be clinically relevant from an antimicrobial resistance surveillance perspective. In-depth analyses at a national level remain limited, with available Romanian studies from the last decade focusing on individual pathogens, often relying on a restricted isolate collection. In this context, we aimed to evaluate antimicrobial resistance profiles and distribution of Salmonella spp., Campylobacter spp., Escherichia coli, Yersinia spp. and Shigella spp. Methods: Data was obtained from records from the Microbiology Laboratory of a tertiary-care hospital serving the south region of Romania, over a 3-year period. Results: Campylobacter spp. had high resistance rates to ciprofloxacin (81.65% for C. jejuni; 85.15% for C. coli) and tetracycline (44.65% for C. jejuni; 56.07% for C. coli). Erythromycin resistance remained low and stable over the study period, with no statistically significant temporal variation; however, C. coli isolates demonstrated significantly higher erythromycin (p = 0.001) and tetracycline (p = 0.008) resistance rates compared to C. jejuni. Overall Salmonella spp. resistance rate to ciprofloxacin was 46.00%, with higher resistance observed in serogroups C (63.64%) and D (52.53%) (p < 0.01). Ampicillin (AMP) resistance varied significantly across years and serogroups, with serogroup B consistently demonstrating higher resistance rates (40.48%) (p < 0.001). E. coli isolates reacting with pathotype-associated O antisera revealed high resistance levels to ampicillin (41.57%), amoxicillin–clavulanic acid (AMC) (38.73%) and sulfamethoxazole–trimethoprim (SXT) (19.25%), with low resistance levels to ciprofloxacin (9.04%) and ceftriaxone (CRO) (9.71%); no significant variation in resistance patterns was identified across years or serological pools, suggesting a relatively stable resistance profile over the study period. Yersinia spp. isolates showed no notable antimicrobial resistance levels. Shigella spp. isolates exhibited high resistance for ampicillin (78.57%), sulfamethoxazole–trimethoprim (68.75%), amoxicillin–clavulanic acid (50.00%) and ceftriaxone (35.41%). Conclusions: This study addressed a recognized gap in Romanian and Eastern European surveillance data and aims to contribute to a stronger evidence base for future epidemiological investigations and antimicrobial stewardship efforts. Resistance rates identified in our study may provide valuable information for comparison with data generated from veterinary, food and environmental surveillance programs, thereby supporting a more comprehensive understanding of antimicrobial resistance (AMR) epidemiology. These findings may additionally contribute to the development of coordinated strategies aimed at mitigating the emergence and spread of AMR. Full article

Background: The global emergence of antibiotic resistance highlights the urgent need for novel therapeutic strategies, including adjuvants and potentiating compounds, against multidrug-resistant bacteria. Pseudomonas aeruginosa is classified by the World Health Organization (WHO) as a critical priority pathogen due to its high resistance potential and its ability to cause severe nosocomial infections. Beauvericin (BEA), a frequently detected mycotoxin, has been reported to exhibit various bioactive properties, including potential antibacterial and potentiating effects. Methods: The interaction between BEA and a last-resort antibiotic, colistin (COL), was evaluated in seven multidrug-resistant P. aeruginosa isolates using a microplate-based growth assay after preliminary MIC tests. Results: BEA at non-inhibitory concentrations (2.5–10 µg/mL) significantly enhanced the antibacterial activity of COL (1 and 2 µg/mL) in six out of seven isolates, resulting in a marked reduction in residual bacterial growth. Conclusions: BEA exhibited no measurable antibacterial activity at the concentrations used in the combination experiments but acted as a strain-dependent potentiator of colistin activity against multidrug-resistant P. aeruginosa. The observed enhancement of colistin-mediated growth inhibition supports the potential of BEA as an antibiotic adjuvant at clinically relevant colistin concentrations and provides a basis for further mechanistic investigation. Full article

Introduction: Vancomycin is a widely used antibiotic in Outpatient Parenteral Antimicrobial Therapy (OPAT) services. The objective of this systematic review was to evaluate the published literature on the efficacy and safety outcomes of outpatient vancomycin therapy. Methods: A systematic search was performed in Embase, Medline ALL, the Web of Science Core Collection, and the Cochrane Central Register of Controlled Trials from database inception until 20 March 2026. Both randomized controlled trials and non-randomized studies published in peer-reviewed journals were included. Study quality was assessed using the Newcastle–Ottawa Scale. Results: A total of 75 studies were included. Clinical success rates of 40.9% to 100% were reported. Reported adverse event (AE) rates ranged widely from 5.7% to 85.7%. Comparative studies suggest a higher risk of nephrotoxicity during intermittent infusion compared to continuous infusion. Reported line-related AE ranged from 1.1% to 5.7% and readmission risks associated with vancomycin use were inconsistent across studies. Conclusions: This systematic review shows that vancomycin is an effective agent to use in OPAT setting, however its use is associated with a risk of adverse events. The findings of this study underscore the need for a dedicated multidisciplinary OPAT team to ensure proper follow-up and tailored vancomycin management in the outpatient setting. Full article

Background/Objectives: Formulating antibiotics as active pharmaceutical ingredient ionic liquids (API-ILs) has been proposed as a strategy to help overcome antimicrobial resistance. However, the effects of API-ILs on bacterial mutation frequency, an increase of which is associated with a higher risk of resistance development, have not yet been assessed. Here, API-ILs based on the antibiotic ciprofloxacin were synthesized using five structurally different counter ions of varying biological activity - low ([Chol]⁺ and [EMMor]⁺), intermediate ([TMC₁₀A]⁺) and high ([TMC₁₆A]⁺ and [TC₈MA]⁺) - and investigated in terms of their antimicrobial activity and mutation frequency in Escherichia coli MG1655. Methods: API-ILs were synthesized according to the CBILS© route. Conductivities and antimicrobial activity (determined by minimal inhibitory concentrations (MICs) and disk diffusion (DD) assays) of API-ILs as well as of individual API and ILs were measured, followed by mutation frequency assays. Results: Five novel ciprofloxacin-based API-ILs were synthesized. Overall, a lower dissociation of API-ILs compared to the respective ILs was observed, indicating presence of stable ion pairs in aqueous solution. All API-ILs retained the antimicrobial activity of ciprofloxacin. A higher mutation frequency (2.6–6.99-fold increase) was observed for API-ILs than for ciprofloxacin alone (1.71-fold increase), when compared to no treatment control, while ILs alone had no or a moderate impact (0.62–1.65-fold increase). Conclusions: Although it is possible to synthesize novel stable API-IL compounds with a high antimicrobial activity using ciprofloxacin and ILs of different structural classes, this can result in increased bacterial mutation frequencies. It is therefore crucial to improve our understanding of how API-ILs can be designed in a safer way. Full article

Salmonella remains one of the most critical zoonotic pathogens in the poultry sector, linked to animal disease, foodborne illness, and the global crisis of antimicrobial resistance (AMR). Poultry acts as a major reservoir, enabling Salmonella transmission from hatchery to retail products through horizontal, vertical, and environmental routes. Despite the use of biosecurity, vaccination, antibiotics, and chemical decontamination, effective and sustainable control across the poultry value chain remains difficult, particularly in the face of rising multidrug-resistant strains and growing consumer concerns over chemical residues. Bacteriophages (phages), viruses that selectively infect and lyse bacteria, have emerged as a promising biological alternative for Salmonella control. Although many studies have reported the effectiveness of phages against bacterial species, including Salmonella, in the poultry industry, reports on their full potential to combat antimicrobial-resistant Salmonella across the entire poultry value chain remain limited. Therefore, this review synthesizes current evidence on the application of phages throughout the poultry value chain, including on-farm interventions, processing plant decontamination, and food packaging and storage. Findings from the reviewed articles indicate over a 90% reduction in Salmonella spp. in poultry farms and post-harvest meat, along with lower mortality in phage-treated groups compared to untreated groups; however, these outcomes depend on several factors (e.g., phage strains, concentrations, application methods, and environmental conditions). Laboratory, pilot, and field studies consistently demonstrate that phage preparations, especially when formulated as cocktails or combined with complementary interventions, can achieve substantial reductions in Salmonella, including antibiotic-resistant serovars, in live birds, eggs, poultry environments, and meat products. Unlike antibiotics and chemical sanitizers, phages act with high specificity, preserving beneficial microbiota and maintaining the sensory and nutritional quality of poultry products. Their safety has been supported by toxicological and genomic assessments, and several phage-based products have obtained regulatory approval, including Generally Recognized as Safe (GRAS) status for food applications in the United States. By integrating efficacy, safety, regulatory, and practical deployment data, this review highlights bacteriophages as a scientifically validated and One Health–aligned tool capable of reducing Salmonella transmission from farm to fork across the poultry value chain, thereby laying the foundation for their future adoption in the poultry industry. Phage-based interventions offer a sustainable pathway to enhance food safety, limit antimicrobial resistance (AMR) dissemination, and strengthen consumer confidence in poultry products. However, the major limitation is the emergence of phage-resistant bacterial strains, as well as the potential involvement of some phages in the transfer of resistance and virulence genes, which could raise public concern. Nevertheless, the use of phage cocktails and whole-genome sequencing, involving tools such as ResFinder and virulence finder, can facilitate the selection of safe phages for application. Full article

Background: The World Health Organization has identified the growing ineffectiveness of antibiotics against resistant pathogens as a global threat to public health, linked to increased morbidity and mortality. In this context, Pseudomonas aeruginosa stands out as a multidrug-resistant, biofilm-forming pathogen whose biofilm formation increases its tolerance to antimicrobials, which has driven the development of anti-virulence strategies as a therapeutic alternative. In this regard, the present study aimed to evaluate extracts and compounds from Piper species in assays targeting the inhibition of biofilm and virulence factors in Pseudomonas aeruginosa, as well as their anti-quorum sensing activity using Chromobacterium violaceum as a biosensor model. Methods: For this purpose, quorum sensing interference was first assessed through inhibition of violacein production using C. violaceum ATCC 12472 as a biosensor model. The modulation of virulence-associated phenotypes in P. aeruginosa ATCC BAA-47 was subsequently examined through inhibition of biofilm formation by crystal violet staining and spectrophotometric quantification of elastase, protease and pyocyanin production. Results: It was found that extracts from P. aduncum, P. sucrense, P. grande, and P. cumanense inhibited biofilm formation in P. aeruginosa and showed potential activity against quorum sensing in the C. violaceum model, while P. ceanothifolium exhibited only antibiofilm activity. Furthermore, hydroquinone-type compounds and benzoic acid derivatives reduced biofilm formation and virulence factors in P. aeruginosa. Conclusions: The results obtained demonstrate antibiofilm and anti-virulence activity, as well as a possible modulation of quorum sensing in model systems, suggesting that Piper species represent a promising source of bioactive compounds. Full article

Background: Antimicrobial resistance (AMR) poses an escalating threat to global health, agriculture, and the environment, demanding urgent multisectoral action under the One Health framework. Despite global awareness efforts, understanding of AMR among the general population remains insufficient, particularly in low- and middle-income countries such as Brazil. This study aimed to evaluate the knowledge, attitudes, and perceptions (KAP) of the Brazilian population regarding AMR. Methods: An online questionnaire was distributed through social media platforms between April and August 2025, resulting in 945 valid responses after data cleaning. Quasi-Poisson models were applied to identify demographic predictors of KAP scores while logistic regression models were used to assess the association between KAP scores and antibiotic use-related practices. Results: Education level was the strongest predictor of higher KAP scores, whereas age and gender showed inconsistent influence. Only 40.3% of respondents correctly identified antibiotics among commonly used medicines, and 25.9% reported proper disposal of antibiotic packaging. More than half (54.2%) were willing to pay more for antibiotic-free products, although only 26.7% had ever noticed such labeling. Network analysis of open-ended responses indicated that concerns about potential health risks and AMR awareness were the primary motivators for purchasing antibiotic-free products. Conclusions: These findings reveal significant gaps in public understanding of antibiotic use and resistance in Brazil, emphasizing the urgent need for targeted educational initiatives, improved public communication, and behavioral interventions to support antimicrobial stewardship and sustainable antibiotic use. Full article

Background/Objectives: Numerous natural compounds have been reported to exhibit anti-virulence properties against pathogenic bacteria. Particularly, plants constitute a rich source of anti-quorum-sensing (QS) and anti-biofilm compounds with highly diverse chemical structures. Notably, several studies reported that plant-derived pentacyclic triterpenoids exert anti-biofilm activity against Pseudomonas aeruginosa without affecting bacterial viability, suggesting that this class of naturally occurring chemical compounds may represent a source of potent and clinically relevant anti-biofilm agents. Methods: To further investigate this hypothesis, we evaluated several commercially available pentacyclic triterpenoid acids of the oleanane, ursane and lupane types for their potential impact on QS mechanisms and biofilm formation in the P. aeruginosa PAO1 model strain. Results: Oleanane-type (oleanolic acid and maslinic acid), ursane-type (ursolic acid and corosolic acid) and lupane-type (betulinic acid) triterpenoids inhibited the expression of the QS-regulated lasB and rhlA genes as well as biofilm formation, without affecting bacterial growth. Among tested compounds, oleanolic and ursolic acids, at 400 µM, exhibited the strongest anti-biofilm activities, with 45% and 40% inhibition, respectively. Fluorescence microscopy revealed a marked disorganization of biofilm architectures, with bacterial communities failing to establish compact cell-to-cell attachment and confluent microcolonies. Further analyses indicated that these triterpenoid acids did not affect the expression of QS-regulator genes (lasR/I and rhlR/I), suggesting that their impact on lasB and rhlA expression and biofilm formation is independent of the las and rhl systems. Conclusions: These findings suggest that oleanane and ursane triterpenoid acids represent promising chemical backbones for the development of strategies aimed at inhibiting P. aeruginosa biofilm formation. Full article

Background: Early-onset ventilator-associated pneumonia (EO-VAP) is a frequent complication in comatose patients requiring endotracheal intubation. This systematic review and Bayesian meta-analysis assesses the effectiveness of antibiotic prophylaxis in preventing EO-VAP in this population. Methods: Randomized controlled trials (RCTs) and observational studies enrolling adult comatose patients (GCS ≤ 8) requiring endotracheal intubation and reporting EO-VAP incidence, late-onset VAP, ICU mortality, 28-day mortality, or ICU length of stay were included. Studies without a control group or not focused on comatose patients were excluded. Following PRISMA 2020 guidelines, a comprehensive search was conducted across three databases from inception to 31 March 2026. Risk of bias was assessed using the RoB2 tool for RCTs and the ROBINS-I tool for observational studies. Results: In accordance with Cochrane Handbook recommendations, only RCTs were included in the quantitative analysis. Five RCTs (735 patients) demonstrated a significant reduction in EO-VAP incidence with antibiotic prophylaxis (RR 0.46 [95% CI: 0.35–0.59], p = 0.001, I² = 0%), with the strongest effect in neurological patients (RR 0.41 [95% CI: 0.32–0.53], NNT = 5.4). No significant effect on mortality was demonstrated. Bayesian analysis confirmed these findings (posterior median RR 0.44 [95% CrI: 0.33–0.59], P(benefit) = 100%). Limitations: The analysis was limited by the small number of RCTs and the absence of data on antimicrobial resistance. Conclusions: Antibiotic prophylaxis reduces EO-VAP incidence in comatose patients, particularly neurological patients. A general recommendation cannot currently be made pending further evidence on mortality and antimicrobial resistance. Registration: This systematic review was prospectively registered on PROSPERO (CRD42024580280). Full article

Background: Carbapenem-resistant K. pneumoniae (CRKP) represents a major challenge in hospitalized patients because of its association with healthcare exposure, restricted antimicrobial options, and adverse clinical outcomes. Microbiological isolation alone does not define invasive disease; therefore, clinical interpretation requires separation of colonization, localized infection, invasive infection, and carbapenem-resistant Enterobacterales (CRE)-associated sepsis. This study evaluated epidemiological features, resistance phenotypes, treatment adequacy, and clinical outcomes among hospitalized adults with K. pneumoniae isolates, using a clinical framework that distinguishes colonization from active infection and invasive disease. Methods: This single-center retrospective observational cohort study included 157 consecutive adults admitted between January and July 2025 to a tertiary-care hospital with at least one microbiologically confirmed K. pneumoniae isolate recovered from clinical specimens and/or CRE surveillance rectal swabs. Isolates were assigned hierarchically to four mutually exclusive phenotypic groups: carbapenem-susceptible K. pneumoniae (CSKP), extended-spectrum beta-lactamase (ESBL)-producing carbapenem-susceptible K. pneumoniae (ESBL), carbapenem-resistant non-carbapenemase-producing K. pneumoniae (CRKP), and carbapenemase-producing K. pneumoniae (CP-KP). A prespecified secondary analysis compared carbapenem-resistant isolates (CRKP + CP-KP) with non-carbapenem-resistant isolates (CSKP + ESBL). Clinical adjudication distinguished colonization-only cases, non-invasive infection, bloodstream infection, device-associated infection, and CRE-associated sepsis; ventilator-associated pneumonia (VAP) was considered when source data allowed reliable attribution. Sepsis was defined according to Sepsis-3 criteria; quick Sequential Organ Failure Assessment (qSOFA) was used only as a bedside screening tool. Statistical tests were selected according to variable type, distribution, and expected cell counts. Results: The cohort comprised 157 unique patients, with a median age of 71 years (interquartile range [IQR], 61–76). Current CRE colonization was documented in 79/154 patients with available colonization status (51.3%). Complete-case in-hospital mortality was higher in the carbapenem-resistant group (CRKP + CP-KP, n = 46) than in the non-carbapenem-resistant group (CSKP + ESBL, n = 111): 11/42 (26.2%) versus 5/108 (4.6%; Fisher exact odds ratio (OR) 7.31, 95% confidence interval (CI) 2.36–22.65; p < 0.001); overall complete-case mortality was 16/150 (10.7%). Multivariable logistic regression for carbapenem resistance (N = 150; five prespecified covariates; events per variable (EPV) = 9.0) identified age 65 years or older (adjusted odds ratio [aOR] 3.78, 95% CI 1.32–10.86), recent hospitalization within 30 days (aOR 2.56, 95% CI 1.16–5.63), and current colonization (aOR 2.96, 95% CI 1.24–7.05) as independent predictors. CRE-associated sepsis was excluded a priori because of definitional circularity with the case definition. Male sex showed a non-significant protective trend (aOR 0.50, 95% CI 0.22–1.12). CRE-associated sepsis showed a strong bivariate association with carbapenem resistance (OR 9.90, 95% CI 3.91–25.09; p < 0.001), and this association is reported descriptively because the variable was excluded from the multivariable model owing to definitional circularity. Model performance was acceptable, with area under the curve (AUC) 0.77, Hosmer–Lemeshow p = 0.95, and Nagelkerke R² = 0.25. Of 99 molecularly characterized isolates, OXA-48-like was detected in 78 (78.8%), NDM in 71 (71.7%), KPC in 6 (6.1%), and NDM + OXA-48-like dual production in 54 (54.5%); VIM and IMP were uniformly negative. Conclusions: In this high-risk hospital cohort, carbapenem resistance in K. pneumoniae was associated with advanced age, recent healthcare exposure, current CRE colonization, and a pronounced unadjusted mortality signal. Interpretation of sepsis and mortality requires explicit separation of colonization from active infection and invasive disease. These findings support intensified CRE surveillance, source-specific clinical interpretation, rapid resistance detection, and risk-adapted empirical antimicrobial strategies in high-risk hospital settings. Full article

Background: Bone and joint infections (BJIs) are a significant clinical challenge due to their tendency to recur, increased healthcare expenses, reduced quality of life, and mortality. Patients with BJIs are a heterogeneous group due to their different clinical presentations as well as patient-related risk factors. Empiric antibiotic regimens are commonly based on deductions from in vitro microbiologic findings, despite the fact that their relative efficacy and optimal antibiotic choices are underexplored. Methods: This retrospective cohort study included 521 patients surgically treated for BJIs at a specialized orthopedic infection unit between 2016 and 2023. Treatment strategies were guided by the Oral Versus Intravenous Antibiotics for Bone and Joint Infection (OVIVA) trial. All patients received a narrow-spectrum Gram-positive–targeted empiric systemic antibiotic regimen determined according to regional recommendations in collaboration with infectious disease specialists. The primary outcome was clinical failure within one year, with a minimum follow-up of 12 months. For the analyses, the patients were divided into three groups based on microbiological susceptibility: susceptible (SusEmp), non-susceptible (NonSus) and culture-negative (CulNeg) patients. Results: The three groups were found to differ significantly in seven patient-related factors: sex, age at primary operation (OP age), BMI, ASA group, diabetes status, peripheral arterial disease status (PAD), and endocrinopathy status (other than diabetes). In performing multivariate analyses, OP age was found to be independently associated with the overall failure rate (p = 0.04) and ASA group (p = 0.047), and PAD (p = 0.043) was independently associated with the secondary outcome of proximal amputation. Patients with non-susceptible pathogens (NonSus) had more than twice the odds of clinical failure (OR: 2.10; 95% CI: 1.12–3.95) and nearly fivefold higher odds of secondary proximal amputation (OR: 4.95; 95% CI: 1.41–23.2) compared with patients with susceptible pathogens (SusEmp). Conclusions: The current study demonstrates that a large group of patients can presumably be treated safely with a more restrictive narrow approach. More studies are needed to identify subgroups suited for the safe use of a narrow-spectrum empiric regimen, hereby reserving the broad-spectrum antibiotics for patients with the right indications and for whom it would have a positive effect on the clinical outcome. Such an approach would justify a more restrictive stewardship of broad-spectrum antibiotic use without negatively impacting patient outcomes. Full article

Background/Objectives: Cefiderocol (FDC) is a siderophore-containing cephalosporin that retains activity against many β-lactamase-producing bacteria, such as New Delhi metallo-β-latamase-producing (NDM) K. pneumoniae. Its use in critically ill patients is still limited, since the recommended dosing regimens are mainly derived from studies on healthy subjects, while critical illness is often associated with critical alterations in drug pharmacokinetics. Therefore, the aim of this study was to investigate FDC pharmacokinetic/pharmacodynamic (PK/PD) parameters in real-life patients based on their body weight and renal function. Methods: Patients with K. pneumoniae infections and indications for FDC were enrolled. Drug quantification in plasma was performed at the steady state at different timings. PK/PD targets of fCmin > 4 mg/L (most common) and more stringent targets of fCmin > 8 and 12 mg/L (4× and 6× the EUCAST breakpoint MIC) were considered in relation to patients’ characteristics, 14 days of microbiological eradication and 30-day mortality. Results: Ten patients were enrolled in this study. Mortality, as well as the failure to achieve microbiological eradication, increased with BMI. In a PK/PD point of view, all patients reached the PK/PD targets of fCmin > 4 mg/L and > 8 mg/L, while only 20% reached a fCmin > 12 mg/L, with a key influence of renal function. However, no significant association was found between PK/PD target attainment and treatment outcomes. Conclusions: Our study may be useful for the real-world use of FDC, highlighting the impact of renal function on the achievement of ideal PK/PD thresholds. Nevertheless, the lack of a significant association between PK/PD and outcomes, partially due to the small sample size, highlights the complex impact of patients’ clinical conditions other than drug PK. Full article

Background/Objectives: Tuberculosis remains a major public health challenge due to the persistence of Mycobacterium tuberculosis (Mtb) and the emergence of multidrug-resistant strains. In this study, Pep-H, an HNP-1-derived antimicrobial peptide with the sequence RRYGTCIYQGRLWAF-NH₂, was used as a compact scaffold to examine how single-residue substitutions at the Cys position affected its biological and functional profile. Methods: A focused single-position substitution panel was generated by replacing Cys with Trp, Ala, Arg, or Met while preserving peptide length and sequence context, and the analogs were computationally prioritized according to their predicted antitubercular potential and contrasting side-chain properties. The peptides were synthesized, purified, characterized by HPLC and mass spectrometry, and evaluated for activity against Mtb H37Rv, cytotoxicity, hemolysis, ethidium bromide accumulation, and DPPH radical scavenging. Results: Pep-H retained the most favorable profile, showing the highest antimycobacterial potency, low hemolysis, favorable selectivity indices, enhanced ethidium bromide accumulation, and the strongest antioxidant response. All Cys substitutions reduced antimycobacterial activity, indicating that none of the tested residues reproduced the integrated biological profile of Pep-H. Conclusions: The contrasting outcomes of the Arg- and Met-containing analogs suggest that increased cationicity or sulfur retention alone was insufficient, while supporting a multifactorial contribution of Cys side-chain chemistry and the local GTCIY environment. Full article

Background/Objectives: Antimicrobial resistance in pediatric infections presents a worsening global public health challenge, with antimicrobial resistance (AMR) accounting for more than one million deaths annually and disproportionately affecting children younger than 5 years of age. Neonates and critically ill children face heightened risk owing to immature immunity, frequent healthcare exposures, and limited therapeutic options. This review synthesizes evidence on the epidemiology, mechanisms of resistance, clinical outcomes, and management of AMR across the full pediatric age range. Methods: PubMed/MEDLINE and Google Scholar were searched for literature from 2014 to 2026 using terms covering antibiotic resistance, pediatric populations, and key pathogens. Approximately 1840 records were screened; 69 sources met all inclusion criteria. A narrative synthesis approach was used, given heterogeneity across study designs and outcomes. Results: Extended-spectrum β-lactamase (ESBL)-producing Enterobacterales, carbapenem-resistant pathogens, and methicillin-resistant Staphylococcus aureus drive substantial morbidity and mortality in children. Approximately one in five pediatric Gram-negative bloodstream isolates are resistant to third-generation cephalosporins, a phenotype independently associated with a roughly three-fold increase in adjusted mortality. Carbapenem-resistant Klebsiella pneumoniae bacteremia carries a 30-day mortality approaching 40%, and isolates in low- and middle-income countries (LMICs) frequently harbor multiple resistance genes. Pneumococcal conjugate vaccine implementation was associated with absolute reductions of 7–11% in the proportion of pediatric pneumococcal isolates that were penicillin-non-susceptible or penicillin-resistant, largely by preventing infections caused by resistant serotypes and by reducing antibiotic selection pressure, rather than through a direct effect on resistance mechanisms; global AMR mortality in children younger than 5 years of age fell by more than 50% between 1990 and 2021. Conclusions: Pediatric AMR reflects intersecting microbiological, clinical, and health-system challenges. Priority actions include scaling antimicrobial stewardship programs, expanding access to rapid molecular diagnostics, integrating whole-genome sequencing into surveillance, conducting pediatric-inclusive randomized trials, and deploying vaccines as primary prevention tools, with particular emphasis on LMICs where the burden is greatest. Full article

Background/Objectives: Neisseria gonorrhoeae is a high-priority pathogen for the development of new therapeutic alternatives. Efflux pumps are attractive drug targets because their inactivation influences N. gonorrhoeae susceptibility to multiple antimicrobials. Since most gonococcal efflux systems are energy-dependent, interference with energy metabolism and membrane transport may indirectly compromise efflux activity. Efflux inhibitors may increase intracellular antibiotic concentration, although this requires validation in resistant strains. The most effective efflux inhibitors interfere with energy metabolism, affecting several physiological processes, including efflux. In this work, we used an in silico drug repurposing strategy targeting proteins involved in membrane transport and energy metabolism in N. gonorrhoeae. A subset of candidate drugs were subsequently evaluated in vitro using only the reference strain N. gonorrhoeae ATCC 49226. Methods: Predicted drug–target interactions were identified using publicly available databases such as DrugBank and STITCH. Minimum inhibitory concentrations (MICs) of selected drugs against N. gonorrhoeae were determined by microdilution. Changes in intracellular ethidium bromide accumulation were assessed by real-time fluorometry as an indirect indicator of possible efflux-related interference. Results: In silico analysis identified 32 predicted targets associated with 57 approved drugs. Triclabendazole and dequalinium showed the lowest MIC values of the tested compounds (2 and 4 mg/L, respectively). Ketotifen and verapamil demonstrated activity consistent with possible efflux interference, as indicated by increased ethidium bromide accumulation. Atovaquone showed adjuvant-like effects in combination assays, suggesting that mechanisms other than efflux-related interference may contribute to its activity. Conclusions: Overall, this preliminary study identifies approved drugs with antimicrobial or adjuvant activity against a single N. gonorrhoeae reference strain, supporting further investigation in clinically relevant and efflux-variant strains. Full article

Objectives: To characterise the bacterial and fungal spectrum of infectious keratitis (IK) in southern China and to evaluate changes in the bacterial profiles and antimicrobial resistance (AMR) over an 8-year period (2017–2024). Methods: This retrospective study included patients with culture-positive IK treated between 2017 and 2024. Corneal scrapings were obtained for microbiological culture and pathogen identification. Antimicrobial susceptibility testing was performed for all bacterial isolates. Microbial distribution and in vitro antibiotic susceptibility were analysed. Results: A total of 2785 microbial isolates were recovered from 2741 patients. Overall, fungal isolates predominated (59.6%), exhibiting a distinct seasonal distribution, with Fusarium (40.2%) and Aspergillus (14.3%) being the most common genera. Among bacterial isolates, Gram-positive organisms were predominant (63.6%). The most frequently identified Gram-positive organisms were coagulase-negative staphylococci (CNS; 34.9%), while Pseudomonas (18.9%) was the most common Gram-negative pathogen. Over the study period, an increase in the proportions of CNS (p < 0.001) and Serratia was observed (p = 0.017), alongside a decline in Pseudomonas (p = 0.009) and Kocuria (p < 0.001). Resistance among Gram-positive isolates increased for penicillin (from 62.3% to 74.4%; p = 0.002) and levofloxacin (from 26.4% to 46.9%; p < 0.001), whereas Gram-negative resistance generally declined. Conclusions: IK in southern China is characterised by persistent fungal predominance and evolving bacterial composition. AMR patterns differ between Gram-positive and Gram-negative organisms, reflecting both shifts in pathogen distribution and species-specific resistance changes, highlighting the importance of continued regional surveillance to guide empirical therapy. Full article