Antibiotic resistance profile of Enterobacteriaceae isolated from healthy pigs in the Republic of Armenia

The rising prevalence of antimicrobial resistance (AMR) among Enterobacteriaceae in livestock presents a significant threat to both animal and human health. This study investigates the antibiotic resistance profiles of Enterobacteriaceae isolated from 160 samples collected from the lymph nodes of healthy pigs in Armenia. Fifty isolates were identified, including Escherichia coli (24), Klebsiella spp. (10), Salmonella spp. (6), Raoultella ornithinolytica (4), Pseudomonas aeruginosa (4), and Proteus mirabilis (2). Resistance was evaluated using the disk diffusion method against 22 antibiotics from nine classes. Alarmingly, 94.5% of isolates were resistant to clarithromycin and 90.3% to erythromycin, while resistance to cephalothin and amoxicillin averaged 71.7% and 56.4%, respectively. All E. coli isolates displayed multidrug resistance (MDR), with resistance to 3–5 antibiotic classes, and other Enterobacteriaceae exhibited MDR spanning up to seven classes. Notably, Proteus mirabilis showed resistance to eight antibiotic classes, underscoring its potential as a reservoir of resistance genes. The findings highlight the risk of zoonotic transmission of AMR pathogens within the food chain. This study underscores the urgent need for antimicrobial stewardship, robust surveillance systems, and improved farming practices to mitigate the AMR crisis in livestock. The results serve as a call to action for policymakers and researchers to address the public health implications of antibiotic resistance in food production systems.