Multidrug-resistant Staphylococcus aureus (MDR S. aureus) is a critical global pathogen, causing significant morbidity and mortality in humans and animals. This pathogen’s ability to form biofilms shields it from antibiotics and facilitates the transfer of resistance genes, underscoring the urgent need for new anti-biofilm strategies. Leveraging microbial ecology and coevolution, probiotic species like Bacillus subtilis are gaining traction as potential therapies due to their ability to reduce S. aureus colonization and virulence. In this study, we isolated and screened 1123 Bacillus strains from concentrated livestock environments where frequent interactions with S. aureus were believed to occur. Subsequent screening identified B. subtilis 6D1, a strain with remarkable ability to inhibit biofilm growth, disassemble mature biofilms, and enhance the antibiotic sensitivity of S. aureus biofilms via Agr quorum sensing interference. Biochemical and molecular analyses revealed that multiple surfactin isoforms and an uncharacterized peptide were responsible for this activity. Compared to commercial HPLC-grade surfactin, B. subtilis 6D1-derived peptides more effectively inhibited biofilm formation across all four S. aureus Agr backgrounds and prevented S. aureus-induced cytotoxicity in HT29 human intestinal cells. Using adaptive laboratory evolution to understand the effects of long-term exposure to anti-biofilm compounds, we found that constant exposure to B. subtilis 6D1 peptides increased biofilm formation when exposure ceased, reduced cytotoxicity, and decreased interspecies competitiveness of S. aureus. These results suggest that while anti-biofilm compounds may reduce the likelihood of selecting for antibiotic resistance, they can still drive bacterial adaptation that promotes biofilm production and possible recalcitrance in the absence of these compounds. Our findings highlight the need to anticipate adaptive trade-offs when developing anti-biofilm therapies. Overall, this study illustrates the potential of exploiting microbial diversity to discover novel anti-biofilm agents, offering promising strategies to combat MDR S. aureus infections and enhance antibiotic efficacy in clinical and veterinary settings.

The limitation of our current arsenal of effective antibiotics, together with the lack of new antibacterial alternatives, is accelerating the onset of a “post-antibiotic era” that threatens many achievements of modern medicine. Recycling existing antibiotics represents a promising strategy to address the antimicrobial resistance crisis. In particular, combining antibiotics with non-antibiotic molecules that target specific resistance mechanisms may be more effective than the discovery of entirely new drugs. Natural products, especially phytochemicals derived from plant secondary metabolism, display antimicrobial activity and are therefore of significant interest for antimicrobial therapy.

In this study, a panel of 50 phytochemical products from different chemical classes (alkaloids, glucosinolate hydrolysis products, phenolics, and terpenes) was evaluated for antimicrobial activity and antibiotic potentiation against Pseudomonas aeruginosa and Staphylococcus aureus. Modes of action were investigated by assessing interference with key physiological processes, including motility, extracellular enzyme production, quorum sensing, membrane integrity, and intracellular content release, in order to clarify the mechanisms underlying antibiotic potentiation. Phytochemicals were also assessed for biofilm control, examining effects on bacterial viability and biofilm structure.

Not all phytochemicals exhibited antimicrobial or antibiotic-potentiating activity. Among the most active compounds, furvina showed strong antimicrobial effects against both P. aeruginosa and S. aureus by disrupting bacterial membranes and inducing intracellular content release. Furvina also potentiated antibiotic activity and inhibited the quorum sensing system of P. aeruginosa and related phenotypes, although it showed no activity against the Agr quorum sensing system of S. aureus. Phytochemicals that interfered with quorum sensing significantly impaired biofilm formation but had limited effects on established biofilms, particularly regarding biofilm dispersal.

In conclusion, phytochemicals can complement antibiotic activity and effectively prevent biofilm formation, although they are unable to induce dispersal of mature biofilms. This approach supports future Nature-based strategies targeting resistance without increasing selective pressure.

Archaea and bacteria share a close phylogenetic relationship and are both ubiquitous environmental components that exchange functional genes. However, it remains unclear how this evolutionary proximity and gene flow influence the carriage of antimicrobial resistance (AMR) genes in archaea or their role in AMR development in co-localised bacterial pathogens. This study investigated the diversity and abundance of antimicrobial resistance genes (ARGs) in archaeal genomes to clarify their role in AMR transmission, particularly through horizontal gene transfer (HGT).

Archaeal genomes from the Genome Taxonomy Database (v2.4.1, release 220), including 10,740 metagenome-assembled (MAGs), 1,601 pure-culture (WGS) and 136 single-cell (SAG) genomes, were screened for ARGs using PanRes (v1.0.2). A total of 47 ARGs were identified in MAGs, 111 in WGS and one in SAG, predominantly distributed within Methanobacteria, Halobacteria, and Thermoproteia, and typically isolated from host-associated samples, high-salinity waters or hot springs. Of these, 34% (MAGs) and 76.9% (WGS/SAG) were biocide or metal ARGs. Using mobileOG-db, 13 mobile genetic elements (MGEs) were identified adjacent to 16 ARGs across the dataset, suggesting potential HGT, particularly in strains from environmental or host-associated samples. Ongoing work involves validating potential HGT between archaea and bacteria through comparative genomic analyses and integrating biosample metadata to trace transfer pathways and ecological distributions, clarifying archaeal contributions to AMR transmission across domains of life.

This study highlights archaea as an overlooked but potentially significant reservoir of mobile ARGs within the One Health continuum, offering new insights into AMR gene exchange and strategies to mitigate global AMR risks.

Introduction: Victoria Jubilee Hospital (VJH) has the largest NICU in Jamaica. Neonatal infections is a leading cause of morbidity and mortality. Quality improvement involves evaluation of antibiotic choices so as to enhance antibiotic stewardship.

Methods: Over three weeks, demographic and clinico-pathological data were reviewed along with indications for escalation and de-escalation of regimens. With no established antibiograms available, a line listing of confirmed infections was used as a proxy of the epidemiological profile of common infections.

Results:

21 neonates aged 0-20 days were reviewed. Gestational ages were 28 - 40 weeks, with 1/3 being premature. Birthweight ranged from 790-3610 gm. 17/21 (81%) received respiratory support, with one death during the period.

Major clinic-pathological conditions included:

• Pneumonia (congenital & ventilator-associated, VAP)
• Necrotizing enterocolitis
• Persistent pulmonary hypertension
• Meconium aspiration syndrome

20/21 neonates were commenced on empiric first line antibiotics – Amoxicillin /Amoxi-clavulanic Acid and Gentamicin. One infant was commenced on 2^nd tier regimen (Piperacillin/Tazobactam & Amikacin; perinatal history of maternal chorioamnionitis), and was escalated to 3^rd tier regimen by day 7 (Vancomycin and Meropenem) due to worsening clinical status.

7/21 infants were escalated to 2^nd tier by day 7 (due to leukocytosis and worsening respiratory status; 6/7 had no positive cultures). One neonate grew Coagulase negative Staphylococcus and was treated for VAP. Although multi-drug resistant, with an in-vivo response, course was extended to 10 days' duration. There was no evidence of de-escalation of antimicrobials during the study period.

Conclusion: Antibiotic selection was primarily guided by overall epidemiological profile and clinical parameters rather microbiological results. Antibiotic de-escalation was not practiced. Stewardship strategies proposed include:

Phase A:

1. Increased availability of blood culture media and support from an in-house microbiology laboratory
2. Provision of adjunct biochemical studies including CRP & I/T ratio

Phase B:

1. Development of de-escalation protocols

Background: There is no consensus regarding the optimal duration of antibiotic therapy for carbapenemase-resistant Klebsiella pneumoniae bloodstream infections (CRKP-BSIs). We sought to compare survival in hospitalized patients with CRKP-BSIs who received shorter versus longer courses of antibiotics.

Methods: We conducted a propensity-score matched (PSM) retrospective multicenter study of adults who were diagnosed with CRKP-BSIs and received antibiotics for ≥ 72 hours. Our outcomes were 30-day mortality, 90-day mortality, and clinical cure. We compared patients treated with short (≤10 days) versus long (>10 days) antibiotic courses.

Results: Our PSM analysis included 97 patients. Of which, 32 patients received short-course antibiotics and 65 patients received long course antibiotics. We identified a significantly higher odds for clinical cure among those who received a course antibiotics (OR 1.25; 95% CI 1.02 – 1.53; p = 0.030). No difference was observed in 30-day and 90-day mortality between short and long antibiotic groups. Among patients with septic shock, receiving a prolonged course was associated with a significantly lower odds of 30-day mortality (OR 0.75; 95% CI 0.62 – 0.90; p = 0.002) and 90-day mortality (OR 0.75, 95% CI 0.65 – 0.86; p <0.001), and higher odds for clinical cure (OR 1.4, 95% CI 1.2 – 1.77; p <0.001)

Conclusion: For patients with CRKP-BSIs, 10 days of therapy may be sufficient; however, a longer duration of treatment may be warranted for septic shock patients.

Laguna de Bay, the largest lake in the Philippines, is a critical multi-use water resource supporting fisheries, agriculture, recreation, and surrounding communities. It receives inflow from 21 river tributaries, draining densely populated areas where backyard farming, untreated wastewater inflow, and agricultural runoff are widespread. Unregulated antibiotic use in livestock and community settings may contribute to the emergence and spread of antimicrobial-resistant (AMR) bacteria across interconnected human, animal, and environmental compartments. Despite growing recognition of AMR as a One Health issue, data on environmental reservoirs of antimicrobial-resistance genes (ARGs) in Philippine freshwater systems remain limited.

In this study, Escherichia coli isolates were collected from river tributaries draining into Laguna de Bay and screened for ARGs using PCR. Isolates positive for extended-spectrum beta-lactamase genes, including blaSHV, bla TEM, and blaCTX-M-1, were selected for whole-genome sequencing using Oxford Nanopore long-read technology. Genome assembly and annotation were performed to characterize resistance gene profiles and their genomic context.

Whole-genome analysis revealed a diverse repertoire of ARGs, including clinically significant carbapenemase and oxacillinase genes not detected through PCR. The detection of blaNDM and blaOXA in environmental E. coli highlights the circulation of high-risk resistance determinants at the human–animal–environment interface. These findings indicate that river tributaries serve as important conduits for AMR dissemination into Laguna de Bay and underscore the value of genomics for One Health-oriented AMR surveillance in the Philippines.

Objectives

The Burkholderia cepacia complex (BCC) comprises significant opportunistic pathogens frequently associated with healthcare-related infections and high levels of multidrug resistance. Due to extensive intrinsic and acquired resistance mechanisms, these infections pose a major therapeutic challenge . This study aimed to investigate the in vitro activity of imipenem/relebactam (IMI/REL) and to evaluate its synergistic effects when combined with amikacin (AMK) and tigecycline (TGC) against clinical BCC isolates.

Methods

A total of 20 non-epidemiologically related clinical BCC isolates were included. Minimum inhibitory concentrations (MICs) were determined by means of the broth microdilution method according to CLSI (2023) guidelines. Synergistic potential was assessed using time-kill assays following CLSI M26-A standards.

Results

IMI/REL showed 80% susceptibility against the tested BCC isolates. Based on MIC₅₀ and MIC₉₀ values, the activity profiles were as follows: IMI/REL (1/4 and 128/4 mg/L), TGC (2 and 4 mg/L), and AMK (32 and 128 mg/L). Time-kill analyses revealed that the IMI/REL–AMK combination produced the most pronounced synergistic effect, achieving ≥3 log₁₀ reduction in bacterial counts relative to the initial inoculum within 24 hours. Sustained bactericidal activity was observed throughout the experiment. No antagonistic interactions were detected among the tested combinations.

Conclusion

Our findings indicate that IMI/REL possesses significant in vitro activity against clinical BCC isolates. The observed synergy and bactericidal activity underscore the IMI/REL–AMK combination as a promising therapeutic strategy for combating infections caused by this challenging, multidrug-resistant pathogen.

Antimicrobial resistance (AMR) is a major global threat to human, animal, and environmental health, particularly in livestock production systems with frequent antibiotic use. Food-producing animals can act as reservoirs for resistant bacteria, facilitating their spread through environmental pathways and the food chain. In this context, Escherichia coli and Klebsiella pneumoniae are widely used indicator organisms for monitoring antimicrobial resistance within the One Health framework.

This study aims to investigate the antimicrobial resistance profiles of Escherichia coli and Klebsiella pneumoniae isolated from cattle farms and to provide preliminary data on resistance patterns in animal and environmental samples. Sampling was conducted in four cattle farms, and 120 samples were collected, including fecal, milk, water, feed, and environmental surface samples. Following collection, samples were pre-enriched in buffered peptone water and subsequently cultured on Endo agar and chromogenic UTI agar for the selective isolation of Enterobacteriaceae. Presumptive colonies were selected based on colony morphology and subcultured to obtain pure isolates, which were identified using conventional biochemical methods.
Antimicrobial susceptibility testing was performed using the disk diffusion method in accordance with CLSI and EUCAST guidelines. The antimicrobial panel included β-lactams (ampicillin, cefotaxime, ceftazidime), fluoroquinolones (ciprofloxacin), aminoglycosides (gentamicin), tetracyclines, and sulfonamides, representing antibiotics commonly used in veterinary practice. Extended-spectrum β-lactamase (ESBL) production was evaluated using phenotypic confirmatory tests.

To date, 70 Enterobacteriaceae isolates have been obtained (62 Escherichia coli and 8 Klebsiella pneumoniae), and sampling is ongoing with an expected final collection of approximately 90 isolates. Antimicrobial susceptibility testing and ESBL screening are currently in progress, and the final analysis will focus on multidrug resistance patterns and the prevalence of ESBL-producing strains. The findings of this study are expected to provide insight into antimicrobial resistance trends in cattle farms and support the One Health approach by highlighting links between antibiotic use in livestock, environmental contamination, and public health risks.

AMR poses a significant threat to global health, with more than 700,000 yearly deaths worldwide. There is an urgent need to reduce antibiotic use, and Primary care and agriculture are major targets for antimicrobial stewardship. Global, regional, and national strategies were developed in the last decade to reduce AMR. However, little progress has been made despite all significant efforts to reduce antibiotic use and AMR. Given the magnitude of the problem, the insufficient strategies to reduce antimicrobial use and the urgency and impact of AMR, there is a need for novel strategies. Traditional, Complementary and Integrative Medicine (TCIM) may provide strategies and solutions that contribute to reducing (inappropriate) antibiotic use, specifically as part of a delayed prescription strategy or as an alternative/ add-on prevention or treatment strategy in both human and veterinary medicine. Homeopathy is one of the most popular TCIM strategies widely used worldwide.The use of homeopathy in the prevention and treatment of infections is based on increasing scientific studies and evidence. To illustrate the substantial role homeopathy could play in helping to reduce the problem of AMR an overview of high-quality studies, including Systematic Reviews and Meta-analysis, Double-Blind Placebo-Controlled Randomised Clinical Trials (RCT) and Real-World Evidence (RWE) studies will be presented. In addition, HRI’s research programme on homeopathy and antimicrobial resistance (ENHANCE), which, to date, includes three systematic reviews and meta-analysis (Otitis Media, Tonsilitis and Sinusitis) and studies on the determination and validation of Core Outcome Sets (COS) for future primary care infection research (Acute Otitis Media, Tonsillitis and Sinusitis) will be introduced. This initiative, through a combination of high-quality research, interdisciplinary collaboration, and standardised methodologies, will strengthen the evidence assessing homeopathic treatment for primary care infections, ensuring safe and effective treatment alternatives for patients and thus contributing to the long-term goal of reducing antibiotic dependence.

Resistance to vancomycin in bacteria (VRB) is primarily mediated by van genes (VRGs), among which the vanA and vanB phenotypes have the greatest clinical significance. They can be transferred between microbial cells via mobile genetic elements, which determines the high epidemic potential of these strains, creating even more dangerous "superbugs". Hospital wastewater (HW) discharged to wastewater treatment plants (WWTPs) is the main anthropogenic source of VRB and VRGs in municipal wastewater, which are finally released into the environment. Therefore, the main goal of this study was to assess the concentration of VRGs in hospital wastewater collected from the whole territory of Poland.

In this study, HW samples were collected in winter and summer seasons from 64 hospitals located in various provinces of Poland. Environmental DNA wasextracted from HW using the FastDNA™ Spin Kit for Feces (MP Biomedicals). The concentration of VRGs was analysed by high-throughput long-read sequencing based on nanopore technology.

In both sampling seasons (winter and summer, 2024), qualitative and quantitative analyses of VRGs revealed considerable differences in gene counts between seasons and regions of HW sample collection. The abundance of VRGs ranged from 0 to 6.55x10² gene copies/Gb and was highest in HW collected in winter from central-eastern Poland. Among ARGs responsible for resistance to vancomycin, vanA and vanB genes presented most frequently and the most common hosts of VRGs were Enterococcus faecium and Staphylococcus aureus.

The results of this study prove that untreated HW is a hotspot for VRGs and VRB to enter the environment. This research can be used to clarify the requirements for hospitals regarding the disinfection of wastewater, as well as the requirements for microbiological quality of wastewater entering WWTPs.