Staphylococcus aureus causes infections ranging from skin and soft tissue infections to life-threatening systemic disease. The convergence of virulence determinants with antimicrobial resistance, particularly in methicillin-resistant S. aureus (MRSA), complicates management. In the United Arab Emirates (UAE), S. aureus is a major contributor to community- and hospital-acquired infections, and regional surveillance from the Gulf Cooperation Council has documented a shift toward community-associated MRSA lineages. Despite this clinical burden, granular molecular epidemiological data from the UAE remain scarce. Fifty consecutive S. aureus clinical isolates were obtained from Thumbay Laboratories, Ajman, UAE (October 2022-August 2023). Identification and antimicrobial susceptibility testing against 23 agents were performed on the MicroScan WalkAway system. Five virulence genes, namely mecA, Panton-Valentine leukocidin (PVL; lukF-S), exfoliative toxins A (eta) and B (etb), and toxic shock syndrome toxin (tst), were detected by conventional PCR. PVL was the most prevalent virulence gene (48%, 24/50), detected exclusively in pus isolates. mecA carriage, confirming MRSA, was identified in 44% (22/50), with PVL-mecA co-occurrence in 22% (11/50). eta was present in 6% (3/50), and etb and tst each in 2% (1/50). Resistance was highest for ampicillin and penicillin (86% each), while full susceptibility (100%) was retained for vancomycin, linezolid, daptomycin, teicoplanin, rifampin, Synercid, and trimethoprim. mecA carriage was significantly associated with resistance to amoxicillin, clavulanate, ampicillin, imipenem, penicillin, oxacillin, azithromycin, erythromycin, and ciprofloxacin (p < 0.05). This study provides the first integrated molecular characterization of key S. aureus virulence determinants, along with a comprehensive antimicrobial susceptibility profile in the UAE. The high PVL prevalence and substantial MRSA burden highlight the need for structured regional surveillance and antimicrobial stewardship, while retained susceptibility to last-resort agents offer actionable guidance for empirical therapy.

Background/Objectives: Although companion animals are recognized as reservoirs of antimicrobial resistant enterococci, it remains unclear whether antimicrobial resistance differs between clinical and commensal isolates, particularly for antimicrobials reserved for human medicine. This study compared antimicrobial susceptibility profiles of clinical and commensal E. faecalis and E. faecium isolates from dogs and cats, focusing on antimicrobials reserved for human medicine under European regulation and EMA/AMEG classification. Methods: A total of 99 isolates (49 E. faecalis and 50 E. faecium) collected between 2022 and 2025 were analysed by broth microdilution, gradient diffusion, and disk diffusion methods. Antimicrobial resistance patterns were compared according to bacterial species and isolate origin. Results:E. faecium exhibited significantly higher resistance rates than E. faecalis, particularly to ampicillin, fluoroquinolones, erythromycin, nitrofurantoin, and vancomycin. Multidrug resistance was widespread, affecting all clinical E. faecium isolates and 72.2% of commensal E. faecium, whereas corresponding proportions in E. faecalis were 64.1% and 40.0%, respectively. Clinical E. faecium isolates showed significantly higher resistance than commensal isolates to antimicrobials commonly used in veterinary medicine, including ampicillin, fluoroquinolones, erythromycin, gentamicin, streptomycin, and tetracycline. Conversely, no significant differences were observed for antimicrobials reserved for human medicine, including linezolid, vancomycin, teicoplanin, tigecycline, daptomycin, rifampicin, and quinupristin/dalfopristin. Conclusions: The higher resistance observed in clinical isolates to veterinary antimicrobials is consistent with the selective pressure exerted by antimicrobial use in veterinary clinical settings, whereas resistance to human-reserved agents may reflect epidemiological processes that are independent of antimicrobial exposure in veterinary clinical settings. Continuous integrated One Health surveillance is essential to monitor the emergence and dissemination of these resistance phenotypes. The AMR profiles observed in companion animals further support the need for integrated One Health surveillance, combining veterinary, human, and environmental data to better understand the emergence and dissemination of resistant enterococci.

Endophytic and rhizosphere bacteria have considerable potential as bioinoculants for enhancing plant growth and improving soil health. However, despite their agricultural importance, their antibiotic resistance profiles remain poorly documented. This study assessed the antibiotic resistance of 31 bacterial strains isolated from the roots, cladodes, and rhizosphere of O. dillenii growing in the coastal zone of Benin. Antibiotic susceptibility was evaluated using the Kirby-Bauer disk diffusion method according to CA-SFM/EUCAST guidelines. Depending on the bacterial genus, each strain was tested against 7 to 12 antibiotics selected from a panel of 19 antibiotics representing 14 antimicrobial classes. The results showed moderate resistance of 40-60% for linezolid and clindamycin. Low resistance of 10-39% was recorded for erythromycin and vancomycin. In contrast, the bacterial resistance to Tetracycline, Amoxicillin, Ciprofloxacin, Fusidic Acid, Gentamicin, Quinupristin-dalfopristin, Rifampicin, and Trimethoprim-Sulfamethoxazole remained extremely low (<10%). No bacterial resistance was detected against Ampicillin, Amoxicillin-clavulanic Acid, Ceftriaxone, Cefoxitin, Cefotaxime, Norfloxacin, or Imipenem. Overall, 9 out of 31 endophytic strains (29.03%) exhibited multidrug resistance. Therefore, this finding provides valuable biosafety data for the selection and registration of bacterial biofertilizers and identifies several promising strains for future agricultural applications.

Antimicrobial resistance (AMR) in Enterococcus poses an emerging One Health concern due to its capacity for environmental persistence and cross-sector transmission. This two-year longitudinal study investigated the spatial and seasonal distribution of Enterococcus across interconnected animal, environmental, and human wastewater compartments in a peri-urban region of western Canada. We aimed to i.) characterize Enterococcus species across varying stages of dairy cow maturity, farm environments and nearby municipal wastewater systems and ii.) determine the AMR profiles and genomic relationships of E. faecalis and E. faecium. Among the 1133 Enterococcus isolates collected, over 24 species were identified, with E. hirae (n = 319) being the most prevalent followed by E. faecium (n = 256) and E. faecalis (n = 223). Species distributions varied significantly by season across most sample types. Antimicrobial susceptibility testing of E. faecalis (n = 58) and E. faecium (n = 61) isolates revealed four, multi-drug resistance E. faecalis isolates, with resistance to tetracycline (18%) and quinupristin-dalfopristin (18%) most common. Genomic analysis of E. faecalis (n = 158) and E. faecium (n = 171) isolates revealed 36 resistance determinants, with aac(6')-Ii, lsa(A), msr(C), tet(M) and tet(L) being the predominant resistance genes. Phylogenomic analysis revealed high diversity within both species, comprising 88 sequence types (STs) for E. faecalis and 100 for E. faecium, including 46 novel STs. Most of the closely related isolates (≤10 SNPs) originated from the same sample type and site (>74%), reflecting localized transmission dynamics. Evidence of cross-domain exchange and seasonal persistence was confined to organic dairy farms, while no genomic relatedness was observed between livestock-associated isolates and those from wastewater. These findings show that dairy-associated Enterococcus populations are diverse yet spatially contained, with limited connectivity to the human wastewater domain. Targeted One Health surveillance can help identify localized points to guide AMR mitigation in regions of intensive dairy production.

Background/Objectives: Enterococcus spp. are important indicators of AMR and potential opportunistic pathogens. Urban green spaces, frequented by dogs and humans, may serve as reservoirs for resistant bacteria. This study assessed the occurrence, AMR profiles, and virulence traits of Enterococcus spp. in dog feces from urban green spaces in Porto (Portugal). Methods: In December 2023 and May 2024, 240 dog fecal samples were collected from 12 urban green spaces across Porto. Enterococcus spp. were isolated using selective culture, identified to species level, and tested for antimicrobial susceptibility following CLSI guidelines. PCR screening was performed for resistance genes (vanA, vanB, erm(A/B/C), vatD/E, tet(M/O/L/K)) and virulence genes (gelE, ace). Environmental and socioeconomic features, including vegetation density (NDVI), presence of water features, and neighborhood deprivation (EDI), were recorded to explore associations with bacterial occurrence and traits. Results: Thirty-two isolates were recovered, mainly E. faecium (n = 9) and E. faecalis (n = 7). High resistance rates were observed to tetracycline (56.3%) and quinupristin/dalfopristin (37.5%), with lower rates for vancomycin, teicoplanin, and ciprofloxacin (3.1%), and imipenem (6.3%). Tet(M) was the most prevalent resistance gene (40.6%), and gelE and ace were frequently detected, often co-occurring with resistance determinants. Distribution of resistance and virulence genes varied across green spaces, with widely used parks showing more isolates. Vegetation density and water features were not directly associated with bacterial recovery. Conclusions: Dog feces in urban green spaces contribute to localized AMR hotspots, acting as potential reservoirs of resistant and potentially pathogenic Enterococcus spp. These findings highlight the importance of One Health strategies for urban sanitation and AMR surveillance.

Antimicrobial resistance (AMR) emerges and circulates across interconnected human, animal, food, and environmental reservoirs; however, food fermentation systems remain underexplored as indicators of local AMR pressure, even though artisanal dairy fermentations may function as natural sentinels of AMR. In this study, we used an artisanal dairy fermentation chain as a One Health model to investigate whether environmentally exposed lactobacilli can reflect stage-associated shifts in resistance. A total of 1.085 isolates representing 16 Lactobacillus species were recovered from the same artisanal dairy matrix at two fermentation stages: day 5 ("Tyrovolia"; n = 518) and day 30 ("Kopanisti"; n = 567). Susceptibility to 14 antibiotics was evaluated by broth micro-dilution, and L. acidophilus was further screened for selected resistance genes. Overall resistance increased significantly from 69.88% (362/518) at day 5 to 77.25% (438/567) at day 30 (p = 0.0059), while multidrug resistance rose from 37.57% to 60.73% of resistant isolates (p < 0.001). Across the 224 species-antibiotic combinations examined, 129 (57.58%) showed an increased upper MIC limit at day 30, and resistance increased significantly for 9 of the 14 antibiotics tested, with the largest rises observed for metronidazole (RR = 7.67), chloramphenicol (RR = 5.74), quinupristin/dalfopristin (RR = 4.11), vancomycin (RR = 2.78), and trimethoprim (RR = 2.43). In contrast, erythromycin and oxytetracycline resistance declined significantly at the ripened stage. In L. acidophilus, 21 resistance genes were detected in 14/70 day-5 isolates and 19 genes in 13/71 day-30 isolates, but marked genotype-phenotype discordance was observed, including matrix-dependent expression patterns for tetM, ermB, and blaTEM. Collectively, these findings show that environmentally exposed artisanal dairy fermentations can enrich resistance phenotypes and may serve as sensitive sentinels of AMR dynamics at the human-animal-environment interface.

Vancomycin-resistant Enterococcus faecium (VREfm) is an emerging pathogen responsible for healthcare-associated infections. For this reason, 44 VREfm isolates collected during 2021-2023 were characterized using phenotypic and genomic approaches. VREfm isolates were identified by MALDI-TOF and antimicrobial susceptibility tests were performed with Vitek 2, Sensititre, or E-test. Sequence type (ST), antibiotic resistance genes, virulence factors and genetic relatedness were determined using Next Generation Sequencing. Forty-three isolates had a VanA phenotype and vanHAX genotype and one had a VanB phenotype and vanHBX genotype. Isolates showed high antibiotic resistance to various antibiotics, but generally remained susceptible to quinupristin/dalfopristin, tigecycline and eravacycline. Two isolates were resistant to linezolid, showing the chromosomal mutation G2576T in domain V of the 23S rRNA gene in one isolate, and the transferable linezolid resistance genes cfr(D) and optrA in the other. Thirty-eight isolates belonged to ST80, one to ST17 (ST80 and ST17 are included in CC17) and one to ST697. Genomic analysis of the ST80 isolates showed that nearly all of them belonged to a single cluster. To prevent further spread of VREfm in the nosocomial environment, in addition to the application of up-to-date infection control strategies and antibiotic stewardship programs, the implementation of genomic surveillance is recommended.