Integrated One-Health analysis of antimicrobial resistance, biofilm formation, and genetic relatedness of Enterococcus spp. at the human-food interface

Abstract

Enterococcus species are opportunistic pathogens and reservoirs of antimicrobial resistance (AMR) that can be transmitted through food chain. This study investigated Enterococcus faecalis and Enterococcus faecium isolated from retail meat, workers and consumers within a One Health framework. A total of 250 samples yielded 50 (20%) isolates, which were analyzed for antimicrobial resistance, virulence genes, biofilm formation, and RAPD-PCR genotyping. This study provides an integrated One Health assessment linking food contamination, occupational exposure, and human colonization. Beef meat showed the highest isolation rate, and E. faecium predominated among consumers. High resistance rates were observed for rifampin (94%, 47/50), erythromycin, and tetracycline (88%, 44/50, each), while vancomycin resistance was low (8%, 4/50). Multidrug resistance was observed in 88% of isolates, and MAR index ranged from 0.07 to 0.86 (average = 0.43). Biofilm formation occurred in 68% (34/50) of isolates, with moderate strength predominated. Resistance genes were widely distributed, particularly tetL (88%, 44/50), while esp (84%, 42/50) and gelE (68%, 34/50) were the most prevalent virulence genes. RAPD-PCR revealed five clusters with moderate discriminatory power (D = 0.729), demonstrating genetic relatedness across sources. Importantly, the co-occurrence of resistance, virulence, and biofilm traits across genetically related isolates highlights the possibility of the food chain as a potential transmission interface. These findings highlight the role of Enterococcus species in AMR dissemination within a One-Health framework.