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Antimicrobial drug resistance of Enterococcus spp. from humans, animals and the environment : a One Health approach
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Resumo(s)
Enterococci, ubiquitous bacteria at the human–animal–environment interface, were studied under a One Health framework to characterise species distribution and antimicrobial resistance across sectors/sub-sectors sampled in 2023–2024. Isolates were collected on Slanetz–Bartley agar with and without vancomycin, genus-confirmed on bile esculin azide agar, and DNA extracted using a boiling method. Genetic diversity was assessed by RAPD-PCR using OPC15 and GTG5, guiding the selection of 74 representative isolates from Healthy Humans (n=14), Sick Humans (n=17), Healthy Animals (n=10), Sick Animals (n=12), Public Surfaces (n=6), Canteen Food (n=9), and Surface Waters (n=6). Species-level PCR identified E. faecalis (63/74; 85.1%), E. faecium (5/74; 6.8%), and a minority that were undetermined; notably, E. faecium was detected only in Sick Humans and Sick Animals. Antimicrobial susceptibility was assessed using the Kirby–Bauer method against twelve agents spanning major classes, with vancomycin resistance confirmed by agar-dilution (16/32 μg/mL). Statistical analysis combined per-antibiotic exact tests with Holm adjustment and across-antibiotics analyses, including Cochran–Mantel–Haenszel tests (two-level contrasts) and binomial GLM likelihoodratio tests (for factors with >2 levels). Resistance was markedly higher in Sick compared with Healthy Humans (38.24% vs 13.69%; pooled Fisher p=9.44 × 10−8; CMH p=6.33 × 10−9; OR=5.354, 95% CI 2.939–9.754). In contrast, Healthy versus Sick Animals showed no significant difference (19.17% vs 20.14%; pooled Fisher p=0.876; CMH p=0.961; OR=1.086, 95% CI 0.535–2.206), and Environmental sub-sectors also showed no significant differences (pooled Fisher p=0.757; GLM-LRT p=0.357). A three-sector comparison initially suggested a pooled difference (p=0.016), which disappeared after adjustment (GLM-LRT p=0.357). Species effects were pronounced: resistance across antibiotics was higher in E. faecium than in E. faecalis (48.3% vs 19.71%; pooled Fisher p=9.17 × 10−6; GLM-LRT p=1.83 × 10−7). Together, these data highlight a concentrated resistance burden at the clinical human interface and a strong species-specific signal, underscoring the importance of integrated One Health surveillance.
Descrição
Tese de Mestrado, Microbiologia Aplicada, 2025, Universidade de Lisboa, Faculdade de Ciências
Palavras-chave
Enterococcus Antimicrobial resistance Vancomycin-resistant enterococci (VRE) One Health Human–animal–environment interface