Antimicrobial resistance in bacteria isolated from the poultry production system in Nepal.

Setting: Twenty poultry farms in five provinces of Nepal were selected for studying bacterial pathogens and their antimicrobial resistance (AMR) patterns.

Objective: To document the proportion of cloacal swabs collected from 3,230 broiler and 3,230 layer chickens from September to December 2021 that grew isolates of Escherichia coli, Enterococcus spp. and Salmonella spp. along with their AMR patterns.

Design: This was a cross-sectional descriptive study.

Results: In broiler birds, Enterococcus spp., Salmonella spp. and E. coli were identified in respectively 36%, 39% and 63% of swabs. In layer birds, Enterococcus spp., Salmonella spp. and E. coli were identified in respectively 31%, 48% and 60% of swabs. For both bird types, there was variation in bacterial prevalence between the regions. For all three bacterial isolates, the lowest antimicrobial resistance was found with amikacin. For the other nine antibiotics tested, >50% of bacterial isolates showed resistance; between 60% and 90% of isolates showed resistance to ciprofloxacin and trimethoprim-sulfamethoxazole. Multidrug resistance ranged from 45% to 46% for Salmonella spp., 37-44% for E. coli and 13-17% for Enterococcus spp.

Conclusion: This study shows that a large proportion of poultry in Nepal are infected with potentially pathogenic bacteria, and these are frequently resistant to commonly used antibiotics. Nepal urgently needs to implement corrective measures.