Dissemination of Enterococcus spp. across One Health Settings: Insights from fingerprinting analysis

Enterococcus spp. are ubiquitous Gram-positive bacteria present in the gastrointestinal tract of humans and animals, as well as in various environmental niches. Over recent decades, Enterococcus spp. have emerged as significant opportunistic pathogens in healthcare-associated infections, with vancomycin-resistant E. faecium identified as a critical health threat. In this context, the One Health concept underscores the interconnection of human, animal, and environmental health, highlighting the importance of intervention fields such as antimicrobial resistance and food safety.

This study aimed to isolate and analyse the genetic diversity of enterococci from a diverse range of samples across One Health domains: sick (n=18) and healthy (n=17) humans, sick (n=13) and healthy (n=14) animals, canteen food (n=11), public transportation surfaces (n=8), and surface water (n=8). Samples were cultured on enterococci-selective media, with and without vancomycin supplementation. Approximately 20% of characteristic colonies were selected and confirmed at the genus level, followed by DNA extraction and RAPD-PCR using primers OPC15 and GTG5 in independent reactions. Amplification analysis and dendrogram construction were performed using the BioNumerics software to obtain relationship patterns within and across One Health sectors.

A total of 148 isolates were obtained from selective media, comprising 81 environmental, 27 animal-, and 35 human-derived isolates, including 24 from vancomycin-supplemented media. Overall, no distinct clustering by sample type or One Health sector was observed, suggesting the widespread dissemination of genetically diverse enterococci across these settings. However, isolates from surface water and clinical samples showed high genetic similarity (≥80–95%), with some clinical clusters also containing isolates from healthy humans.

These findings confirm the widespread dissemination of enterococci across One Health sectors, including presumptive vancomycin-resistant enterococci, and underscore the need for further biosurveillance studies.