Search Results (15,494)

Background: Acinetobacter baumannii (A. baumannii) is a critical-priority pathogen of major concern in healthcare settings. Colistin remains a last-resort antibiotic for multidrug-resistant (MDR) A. baumannii infections; however, resistance is increasingly reported worldwide yet remains understudied in Bahrain. Reliable detection methods and understanding clonal dissemination are essential for infection control. Objectives: This study aimed to (1) determine the rate of colistin resistance in 102 clinical A. baumannii isolates from Bahrain, (2) evaluate the diagnostic performance of the colistin agar test (CAT) and E-test against broth microdilution (BMD method), and (3) assess clonal relationships using BOX-PCR fingerprinting. Methods: 102 clinical isolates from multiple hospitals in Bahrain underwent susceptibility testing via the BMD method, CAT, and E-test; screening for mcr-1 to mcr-5 genes; and BOX-PCR DNA fingerprinting. Results: Colistin resistance was detected in 14.7% of isolates by BMD method, higher than regional and global averages. All resistant isolates were mcr-negative, suggesting chromosomally mediated resistance. CAT showed 86.7% sensitivity, 98.8% specificity, and a 13.3% very major error rate. The E-test failed to detect resistant isolates (very major error 100%). BOX-PCR revealed predominant clonal relatedness with intra- and inter-hospital spread. Conclusions: Colistin resistance in A. baumannii from Bahrain exceeds regional and global levels, likely driven by chromosomal mechanisms under selective pressure. The BMD method remains the gold standard for colistin testing, while CAT may serve as a screening tool requiring confirmation. Strengthened stewardship and infection control measures are vital to contain dissemination. Full article

Accurate detection and monitoring of antimicrobial resistance (AMR) in Helicobacter pylori mainly rely on phenotypic methods and culture, which can sometimes fail when bacterial load is low or after recent treatment. We investigated whether gastric biopsies classified as H. pylori-negative by standard diagnostic techniques still contain detectable bacterial DNA, including regions linked to AMR, and assessed whether selected DNA fragments can mediate allelic exchange in vitro. Gastric biopsies from 46 dyspeptic patients in the Democratic Republic of the Congo (including 23 phenotypically positive and 23 phenotypically negative individuals) were analyzed using long-read amplicon sequencing of seven resistance-associated loci, selective whole-genome amplification (sWGA) followed by long-read sequencing of H. pylori-enriched reads, and a proof-of-concept natural transformation assay. Phenotypically negative biopsies exhibited significantly lower sequencing depth across multiple loci (including 23S rRNA, gyrA, gyrB, and pbp1A; p = 0.003–0.014), indicating a reduced H. pylori DNA burden. However, AMR-associated mutations linked to various antibiotic classes were found in both groups. sWGA enabled recovery of fragmentary H. pylori sequence data from phenotypically negative samples, including reads that map to resistance- and virulence-associated genes. In vitro, 23S rRNA A2143G amplicons from both phenotypically positive and negative biopsies produced clarithromycin-resistant transformants in strain 26695. These findings indicate that phenotypically negative gastric biopsies might contain low-abundance and fragmentary H. pylori DNA. Although certain DNA fragments can mediate allelic exchange under controlled in vitro conditions, these results do not confirm bacterial viability, active infection, or clinically relevant in vivo resistance transfer. Therefore, they should be interpreted with caution in molecular AMR surveillance and detection contexts. Full article

In intensive animal production, the overuse of antibiotics has exacerbated bacterial antimicrobial resistance and environmental pollution. Together with gut microbiota dysbiosis and recurrent disease outbreaks, these challenges severely constrain the sector’s high-quality development. Quorum sensing (QS), a cell-density-dependent bacterial communication mechanism, can be modulated through agents that specifically inhibit or activate QS circuitry to regulate microbial community functions. Such QS modulators possess notable advantages, such as environmental benignity and high target specificity, and thus offer innovative strategies to decrease antibiotic reliance, enhance production efficiency, and reduce environmental emissions. This review examines QS modulators sourced from plants, microorganisms, animals, and synthetic processes, while highlighting key challenges such as environmental interference, resistance development, high costs, and the lack of standardized biosafety evaluations. Future research should focus on enhancing specificity, stability, affordability, and safety, with an emphasis on rational design, synergistic systems, improved manufacturing processes, and multi-target modulators. This review may provide a theoretical basis for translating QS-regulation technologies into farm-level applications, thereby advancing sustainable animal production and antibiotic-free husbandry. Full article

Plant-parasitic nematodes (PPNs) rank among the most economically destructive soilborne pathogens worldwide, causing annual crop losses estimated at USD 125–175 billion. Traditional management of plant parasitic nematodes has depended significantly on synthetic nematicides; however, increasing regulatory constraints, environmental pollution, and the rise of resistant nematode populations have generated an urgent need for sustainable alternatives. Humic substances (HS), comprising humic acids, fulvic acids, and humins derived primarily from leonardite and lignite, represent biologically active components of soil organic matter. Their different functional groups, like carboxylic, phenolic, and carbonyl groups, have direct nematicidal and nematostatic effects by stopping eggs from hatching, slowing down juvenile development, and lowering infectivity. They also indirectly improve soil structure, nutrient bioavailability, and the composition of the rhizosphere microbiome. Plant growth-promoting rhizobacteria (PGPR), particularly Bacillus spp. and Pseudomonas spp., suppress PPN populations through antibiotic biosynthesis, cuticle-degrading hydrolytic enzymes, nematostatic volatile organic compounds, and elicitation of induced systemic resistance (ISR). This review methodically analyzes the individual and synergistic processes by which HS and PGPR inhibit PPNs and enhance plant growth. Humic compounds strongly promote PGPR rhizosphere colonization, augmenting microbial metabolic activity and bioinoculant stability, hence producing combinatorial suppressive effects unattainable by either input independently. The combined HS-PGPR approach is reliable and environmentally sustainable for comprehensive nematode control, requiring multidisciplinary research to achieve global sustainable agriculture. Full article

Background/Objectives: Patients in long-term care hospitals (LTCHs) are at increased risk of harboring antimicrobial-resistant organisms due to frequent healthcare exposure and multiple comorbidities. This retrospective observational study aimed to compare the antimicrobial susceptibility of bacterial isolates from LTCH-onset infections (LTCHIs) with those from community-acquired infections (CAIs) in elderly patients. Methods: This study was conducted at a 700-bed urban tertiary university hospital and included patients aged ≥65 years with positive cultures for bacteremia, lower respiratory tract infections (LRTIs), or urinary tract infections (UTIs) within 48 h of admission. Medical records, including antimicrobial susceptibility test results, were reviewed for a total of 1780 patients and their isolates. Antimicrobial susceptibility patterns were compared between LTCHI and CAI patients. Results: Patients with LTCHI exhibited significantly higher antimicrobial non-susceptibility than those with CAIs across multiple pathogens and antimicrobial classes (p < 0.05). In bacteremia, Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae from LTCHI cases showed increased non-susceptibility to β-lactams and fluoroquinolones. In LRTIs, Pseudomonas aeruginosa and Acinetobacter baumannii demonstrated high non-susceptibility to carbapenems (52.9% and 90%, respectively) and aminoglycosides. In UTIs, LTCHI isolates exhibited broader resistance among Enterobacterales and P. aeruginosa. Notably, the proportion of multidrug-resistant organisms, including carbapenem-resistant Enterobacterales (15.4–50.0%) and carbapenem-resistant Acinetobacter baumannii (90.5%), was substantially higher in the LTCHI group across all infection sites. Conclusions: Elderly patients with LTCHI are more likely to harbor antimicrobial-resistant pathogens than those with CAIs. Careful consideration of LTCHI origin is therefore essential for empirical antibiotic selection and for strategies aimed at limiting further resistance. Full article

Microbial inoculation is widely used to improve composting performance, yet its effectiveness hinges on inoculum composition, substrate characteristics, and composting technology, which remain poorly understood. This study compared single versus mixed inoculants across different substrates and assessed their interactions with biochar amendment and nanomembrane covering, focusing on organic matter transformation, inorganic nutrient dynamics, and biological pollution control. Mixed inoculation significantly improved heating performance in cattle manure compost compared to single strains (p < 0.05) and sustained thermophilic conditions in sludge-sawdust compost, but showed limited impact in chicken manure-sludge compost. It reduced humic acid (HA) accumulation in chicken manure-sludge compost (14.29% to −39.28%) while increasing HA content in sludge-sawdust compost (3.55–5.41 g/kg, p < 0.05). Inorganic nitrogen retention was enhanced; specifically NO₃⁻-N concentrations rose by 175.1–222.6% in the chicken manure-sludge and by 6.7–17.9% in the sludge-sawdust compost. Microbial community analysis indicated enrichment of inoculant strains during the thermophilic phase, supporting nitrogen conservation and humification. However, inoculation increased potential pathogenic bacteria by over 51.2% across all composts and enriched predicted antibiotic resistance genes (ARGs) by 9.9–22.96% in chicken manure-sludge compost, while reducing the membrane covering’s inhibitory effect on predicted ARGs (rebound by 29.5%). Moreover, we found that the predicted ARG profiles, derived from 16S-based PICRUSt2 functional inference, covaried strongly with microbial community structure, with environmental factors such as organic carbon shaping predicted ARG dynamics mainly through indirect effects on microbial communities. These findings highlight that while mixed inoculation boosts composting efficiency, it also raises biosafety concerns. Thus, a comprehensive evaluation integrating organic, inorganic, and biological perspectives is essential before promoting thermophilic inoculants. Full article

Background: Clostridioides difficile is classified within the first 18 threats for antimicrobial resistance and is the leading cause of hospital-acquired enteric infection. Community-associated cases have notably increased in recent decades, highlighting that accurate and up-to-date statistics characterizing the epidemiology of C. difficile infection (CDI) are critical. Methods: We conducted a retrospective (2019–2023) case-control study evaluating the prevalence of CDI in 249 stool samples from hospitalized patients in the sanitary region III of Buenos Aires, Argentina. The presence of C. difficile was detected by combining EIA, PCR, and toxigenic culture via a diagnostic algorithm. Clinical and demographic data from patients were analyzed to identify CDI-associated risk factors. We also conducted a systematic review and a meta-analysis contrasting our results with 38 studies selected from different countries. Results: One in five patients presented C. difficile as the etiological agent of diarrhea. Eighty percent of the CDI+ cases carried toxigenic strains, with a third of cases associated with community environments. Age ≥ 69 years, previous use of antibiotics, previous hospitalization, and previous episodes of CDI emerged as predisposing factors for CDI in our study cohort. In an exploratory evaluation of clinical data, CDI+ patients showed higher leukocytes and platelets counts, a decreased basophil count, and increased urea concentration. At the global level, the meta-analysis reinforced advanced age, previous consumption of antibiotics, previous consumption of proton pump inhibitors, previous hospitalization, and previous CDI as risk factors for CDI. Conclusions: These results emphasize the importance of continued epidemiological surveillance of CDI. Our findings confirm previously described risk factors, both in our cohort and at the global level. Exploratory alterations in laboratory parameters were observed, although their clinical relevance and specificity require further investigation. Full article

Background/Objectives: Skin and soft tissue infections (SSTIs) represent a significant clinical challenge, largely due to the high prevalence of antibiotic-resistant Staphylococcus aureus, particularly methicillin-resistant S. aureus (MRSA). Treatment is further complicated by biofilm formation, which reduces antibiotic efficacy. The limitations of conventional therapies highlight the need for alternative approaches. Phage therapy has emerged as a promising biological strategy; however, its effectiveness may be constrained by factors such as phage instability and biofilm regrowth. This study aimed to enhance phage-based treatment by combining a newly isolated phage, vB_Sau-E, with lactoferrin (Lf), a multifunctional protein of the innate immune system. Methods: Phage vB_Sau-E was characterized in terms of its infection dynamics and lytic activity. Biocompatibility was further examined using human skin cell lines. The potential effect of Lf was assessed by evaluating its impact on phage infectivity and stability under a range of environmental conditions and by checkerboard assay. Results: Phage vB_Sau-E belongs to the Silviavirus genus in the Herelleviridae family. It was shown to infect 12 out of 22 tested clinical MRSA isolates, with 10 strains identified as good hosts. The phage has a ~30 min life cycle, and ~50 progeny virions are released after bacterial cell lysis. We have also observed that Lf increased plating efficiency and enhanced phage stability at a pH of 5.5 and at −20° C. It also proved to have an additive antibacterial effect, though this was observed to be strain-dependent. Conclusions: Lactoferrin functions as a stabilizing adjuvant for phage vB_Sau-E. Its additive effect supports the development of more effective, biofilm-targeting therapies for staphylococcal SSTIs. Full article

Background/Objectives: The aquaculture industry represents a fundamental food sector. One of the main limiting factors for this sector is related to bacterial diseases, for which antibiotics have been widely used worldwide for decades. In recent years, a more conscious approach to the use of antimicrobials within the framework of the One Health approach has increased the need for alternatives capable of helping with disease management while avoiding the onset of antimicrobial resistance phenomena. Antimicrobial peptides, which have a broad spectrum of action against pathogens, are a promising solution. Methods: In this work, we investigated the capability of three peptides (Trematocine, Chionodracine, and Cnd-m3) isolated from Antarctic fish to target bacterial and viral pathogens affecting aquaculture. Successively, we investigated their cytotoxicity versus a continuous embryonic cell line (DLEC) derived from European sea bass and their haemolytic activity against fish erythrocytes. Moreover, we evaluated their immunomodulatory effect. Results: Regarding antibacterial properties, Cnd-m3 was identified as the best peptide, demonstrating good bactericidal and bacteriostatic activity against various bacterial strains, including Lactococcus garvieae. Concerning this bacterium, ANS permeability assays showed that the Cnd-m3 peptide has a great ability to interact with its outer membrane, while TEM analysis revealed that the peptide, after destabilization of the cell membrane, interacts with nucleic structures. Considering the antiviral activity, Trematocine was effective against two tested pathogenic enveloped viruses. Moreover, the toxicity of Trematocine and Cnd-m3 was evaluated by investigating their cytotoxicity against a cell line derived from Dicentrarchus labrax and haemolysis against sea bass erythrocytes. Both revealed good selectivity towards pathogens at the lowest concentration. Finally, Cnd-m3 manifested light in vitro immunomodulatory properties. Conclusions: Overall, these data provide a solid basis for future studies assessing the potential applications of two of the tested peptides in aquaculture. Full article

Antibiotic resistance is a growing global health threat. However, its evolution cannot be fully understood without considering antibiotic tolerance and persistence. Persister cells are phenotypic variants that survive lethal antibiotic exposure without heritable resistance, primarily through growth arrest, metabolic slowdown, and stress-adaptive states. Although persistence has been viewed as a transient survival phenomenon, increasing evidence suggests that it may also have a genetic basis by preserving populations during antibiotic-induced bottlenecks and enabling regrowth, mutation, and selection under certain conditions. This review examines the molecular mechanisms underlying persister formation, including toxin–antitoxin systems, stringent-response signaling, ATP depletion, translational arrest, and stress-response networks. We discuss how persistence contributes to antibiotic tolerance in biofilms, host environments, and recurrent infections, and how repeated antibiotic exposure may promote stepwise evolution from phenotypic survival to stable resistance in specific contexts. Evidence from experimental evolution, clinical observations, and system-level analyses supports a potential but context-dependent link between persistence and resistance. We also highlight therapeutic strategies targeting persister cells, including antipersister compounds, metabolic activation, combination therapies, bacteriophages, and alternative approaches. Finally, we outline future research directions, emphasizing single-cell technologies, systems biology, longitudinal clinical studies, and evolution-informed treatment design. A comprehensive understanding of persistence and its evolutionary implications is essential for improving treatment efficacy and limiting the emergence of long-term antibiotic resistance. Full article

The term bacterial biofilm refers to a complex community of microorganisms embedded within a self-produced matrix of extracellular polymeric substances. This structural organization creates an environment that, when present in an infectious context within a living organism, limits the effectiveness of conventional antibiotic therapy. Consequently, such conditions substantially promote the development of antibiotic resistance. The decline in the discovery of novel antibiotic agents, coupled with a concurrent increase in the prevalence of multidrug-resistant microorganisms, has intensified the search for alternative strategies to combat such infections. At the same time, advances in nanoscience have stimulated substantial research into the use of micro/nanorobots for the eradication of bacterial biofilms. These devices, engineered at the micro- to nanoscale, are capable of targeted intervention in otherwise inaccessible sites. However, the development of such “microscopic therapeutic agents” is still at an early stage. To date, the vast majority of available data has been derived from in vitro studies, while evidence regarding their feasibility, safety, and therapeutic effects in living organisms remains limited. This review discusses their antimicrobial mechanisms and critically evaluates the current evidence concerning their in vivo applications. Full article

Background: Antimicrobial stewardship programs (ASPs) are critical for promoting rational antibiotic use. While early implementation outcomes have been reported, extended follow-up sustainability and the impact on high-priority broad-spectrum antibiotics in South Korean secondary/tertiary hospitals require further validation. This study aimed to evaluate the extended outcomes and sustainability of an ASP over a 14-month period. Methods: This retrospective, single-center study analyzed ASP activities from January 2025 to February 2026 at a tertiary hospital in South Korea. Interventions included prospective audit and feedback (PAF) for restricted antibiotics and recommendations for prolonged prescriptions (≥14 days). Primary outcomes were the monthly rejection rate of restricted antibiotics and the acceptance rate of ASP interventions. Secondary outcomes included the days of therapy (DOT) per 1000 patient–days for meropenem and piperacillin/tazobactam (Pip/Taz). Results: During the 14-month period, the ASP intervention acceptance rate increased significantly from a mean of 72.0% in the implementation phase (January–April 2025) to 81.2% in the stabilization phase (May 2025–February 2026) (p = 0.035). The DOT for Pip/Taz decreased significantly from 169.4 to 151.8 per 1000 patient–days (p = 0.002), with a significant negative correlation identified between the intervention acceptance rate and Pip/Taz consumption (r = −0.625, p = 0.017). Although overall meropenem DOT showed seasonal fluctuations without reaching statistical significance across phases, a year-over-year comparison revealed a 7.5% reduction in meropenem DOT (January–February 2025: 54.8 vs. January–February 2026: 50.7 per 1000 patient–days). The rejection rate for restricted antibiotics declined from 3.8% to 2.6%, suggesting that clinicians increasingly self-regulated inappropriate prescribing attempts. Conclusions: The ASP demonstrated extended follow-up sustainability with a significant reduction in the consumption of key broad-spectrum antibiotics. A progressive increase in clinician acceptance of ASP interventions from 72.0% to 81.2%, combined with a concurrent decline in the restricted antibiotic rejection rate, reflected a measurable shift in institutional prescribing culture and confirmed the successful transition to a stabilized program. These findings support the necessity of sustained multidisciplinary ASPs, even in resource-limited settings, to combat antimicrobial resistance effectively. Full article

Background: Following a significant decline during the 2020–2021 SARS-CoV-2 pandemic, Mycoplasma pneumoniae (MP) experienced a resurgence across Europe in 2023–2024. Although macrolide-resistant MP has increased globally, severe disease can occur even in the absence of resistance, which highlights the importance of rapid molecular characterization for clinical purposes. In this context, clinical severity is often improperly used as a surrogate marker of macrolide resistance, potentially driving unnecessary antibiotic escalation. Methods: We report a severe MP pneumonia occurring during the 2023–2024 resurgence and evaluate macrolide resistance through a rapid two-step workflow (Real Time-PCR screening for A2063G/A2064G followed by confirmatory 23S rRNA sequencing), to assess whether severity predicts resistance and to support antibiotic stewardship. Results: The patient developed acute hypoxic respiratory failure (PaO₂ 54.9 mmHg; P/F ratio 110), extensive centrilobular micronodules on chest CT imaging, significant systemic inflammation and elevated liver enzymes. Respiratory support was escalated from a Venturi mask to a high-flow nasal cannula and BiPAP. MP infection was confirmed by multiplex Real Time-PCR (RT-PCR) and supported by positive IgM/IgG serology. RT-PCR targeting A2063G/A2064G mutations revealed no resistance-associated variants, and Sanger sequencing of an 807 bp 23S rRNA fragment confirmed a wild-type genotype. Despite severe hypoxemic respiratory failure, no resistance-associated variants were detected, documenting a clear severity–genotype mismatch. Clinical and radiological improvement followed second-line antibiotic therapy. Conclusions: Severe MP pneumonia can occur despite the absence of macrolide resistance. During MP re-emergence, clinical severity should not be used to infer macrolide resistance. Integrating nucleic acid amplification test (NAAT) diagnosis with rapid genotyping/confirmatory 23S rRNA sequencing can prevent misclassification, reduce unwarranted broad-spectrum escalation, and strengthen antimicrobial stewardship decisions. Full article

Background: Farm-level antimicrobial stewardship in swine production requires indication-specific knowledge of treatment patterns and the herd-level features associated with them. Methods: We analyzed questionnaire-based data collected in 2015 from 13 Hungarian swine farms covering 15,725 sows and their progeny. The survey captured production indicators, pathogen occurrence, vaccination, resistance-testing practices, drug costs, and disease-group-specific antimicrobial use. As a separate, non-mergeable descriptive temporal comparator, we also considered independent digital farm-monitoring data from three large-scale swine herds from 2022 to 2024. Results: The most frequently reported pathogens were Mycoplasma hyopneumoniae (13/13 farms), Lawsonia intracellularis (12/13), Escherichia coli (12/13), swine influenza virus (11/13), and Streptococcus suis (10/13). S. suis ranked as the leading damaging pathogen on 69% of farms. Among farms with antibiotic cost data (9/13), antibiotics accounted for a mean of 31.8% of veterinary drug expenditures. Among farms with treatment-by-indication data (8/13), the highest relative frequency of reported treatment events was linked to porcine respiratory disease complex, where doxycycline represented 38% of reported PRDC treatment events. Colistin dominated E. coli-associated diarrhea control, whereas beta-lactams were central for S. suis-related disease. In the 2022–2024 comparator dataset, enteric and respiratory disorders and arthritis remained the main recorded health problems, but corrected antimicrobial use was markedly lower in the later dataset. Conclusions: Antimicrobial use showed clear disease-group-specific patterns, supporting syndrome-focused stewardship rather than generic reduction targets. Full article

Staphylococcus aureus nasal carriage contributes to asymptomatic transmission in both community and healthcare settings. This study aimed to characterize S. aureus strains isolated from students of the Pomeranian Medical University in Szczecin, Poland, using phenotypic and genotypic methods. A total of 175 S. aureus strains were isolated from the nasal vestibules of 800 students between 2014 and 2015. Species identification and antimicrobial susceptibility testing were performed using standard microbiological methods, while virulence-associated genes and agr groups were analyzed using Single-PCR and Multiplex-PCR assays. Genotypic diversity was assessed by pulsed-field gel electrophoresis (PFGE). The prevalence of S. aureus nasal carriage among students was 21.9% and did not differ according to faculty or year of study. Most isolates (84.0%) were susceptible to all tested antibiotics, and no methicillin-resistant S. aureus (MRSA) strains were detected. All strains carried the hla gene, whereas hld and hlg were identified in 93.7% and 93.1% of isolates, respectively. In addition, the tst gene was detected in 22.3% of strains, while the lukS-PV/lukF-PV genes were identified in only one isolate (0.6%). The most prevalent enterotoxin genes were sep (17.1%) and sea (13.7%), whereas genes of the egc cluster, including seg, sei, and seo, were detected in 53.7% of isolates. Significant associations were observed between specific egc gene combinations and superantigen gene profiles, including increased frequencies of sec, sel, and tst genes (p < 0.001). The predominant agr type was agr-1 (49.7%), followed by agr-3 (28.6%) and agr-2 (20.0%). Strains carrying agr-1 more frequently harbored the g i m n o cluster as well as the sec, sel, and sep genes, whereas agr-3-positive isolates were significantly associated with the g i m o u and g i o u clusters and with the presence of tst, sea, and seh genes (p < 0.05). PFGE analysis demonstrated substantial genetic heterogeneity among the isolates, with no evidence of a predominant clonal lineage. These findings indicate a heterogeneous, non-epidemic population structure of S. aureus strains circulating among university students and highlight the considerable diversity and interrelationships of virulence-associated genetic profiles within this population. Full article