The Prevalence of Antimicrobial Resistance Genes in the Environments of Small Ruminant Farms from Central Portugal

Background: Antimicrobial resistance is a pressing global concern affecting both human and animal health, with environment playing a key role in the dissemination of resistance determinants. This study aimed to investigate the presence of antimicrobial resistance genes (ARGs) associated with tetracyclines, β-lactams, macrolides, and sulfonamides in environmental matrices collected from 65 sheep and goat farms in central Portugal. Methods: Environmental samples, including water, soil, pasture, and bedding, were analyzed through qPCR for the detection of clinically relevant ARGs. Results: ARGs were detected in 83% of the samples, with over half exhibiting genes from three or more antibiotic classes, suggesting potential multidrug resistance. β-lactamase genes were the most prevalent, followed by those conferring resistance to tetracycline and sulfonamide resistance, while macrolide resistance genes were least frequent. The distribution of ARGs varied by farm type, host species, and municipality. Conclusions: These findings suggest that small ruminant farms serve as important reservoirs for ARGs. The results underscore the need for systematic surveillance and further research into the ecological and genetic factors driving ARG persistence and dissemination in extensive livestock systems, including proper waste management strategies to limit the spread and persistence of antibiotic resistance and mitigate broader public health risks.

Descrição

Funding Information: This work was funded by the RumiRes project—“Vigilância epidemiológica de resistências antimicrobianas e resíduos medicamentosos em Pequenos ruminantes da Região Centro” (Ref. PRR-C05-i03-I-000190); Science and Technology Foundation through funds for GHTM-UID/04413/2020 e LA-REAL—LA/P/0117/2020 and CERNAS UIDB/00681/2020. Publisher Copyright: © 2025 by the authors.

Palavras-chave

antimicrobial resistance goat Portugal sheep Microbiology Biochemistry Pharmacology, Toxicology and Pharmaceutics(all) Microbiology (medical) Infectious Diseases Pharmacology (medical) SDG 3 - Good Health and Well-being SDG 11 - Sustainable Cities and Communities

URI

http://hdl.handle.net/10362/188723

DOI

10.3390/antibiotics14060576

Coleções

Home collection (IHMT)

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