Sessions

Antimicrobial resistance (AMR) is a globally significant issue, posing increasingly serious challenges in both human and veterinary medicine. Multidrug-resistant Enterococcus species, particularly E. faecalis and E. faecium, play a prominent role in the development of nosocomial infections and also possess notable zoonotic potential. The poultry microbiome may serve as a reservoir for AMR genes, which can be transmitted to human pathogens through mobile genetic elements.

The aim of this study was to investigate the resistome of 73 Enterococcus isolates derived from domestic poultry farms in Hungary using next-generation sequencing (NGS). Bioinformatic analysis identified a total of 1,227 antimicrobial resistance genes representing 179 distinct gene families. The identified resistance mechanisms were categorized by antibiotic class, with particular emphasis on genes associated with glycopeptide (vancomycin) and oxazolidinone (linezolid) resistance.

In the context of glycopeptide resistance, key components of the vanC operon, including vanRC, vanSC, vanTC, and vanXYC were detected, often co-occurring within the same isolates. Regarding linezolid resistance, the predominant genes included lsaA, emeA, and the efflux pump genes efrA and efrB, which may contribute to reduced intracellular antibiotic concentration.

Our findings indicate that Enterococcus strains isolated from poultry harbored a substantial number of antimicrobial resistance genes, including those conferring resistance to last-resort antibiotics used in human medicine. These results underscore the importance of monitoring and regulating AMR reservoirs in livestock production and support the practical relevance of the One Health approach.