Antimicrobial resistance profiling of Salmonella and Escherichia coli isolates from conventional poultry farms in Hossana Town, Central Ethiopia.

Antimicrobial resistance (AMR) is an increasing One Health threat posing serious challenges to both human and animal health and the health of the environment they share. The highly growing livestock production with high rate of antimicrobial use and misuse is very important source of the emergence and spread of AMR mainly in association with foodborne zoonotic pathogens, such as Salmonella and Escherichia coli O157:H7. A cross-sectional study was conducted from October 2023 to May 2024 in conventional poultry farms in Hossana Town, Central Ethiopia, to assess the AMR profiles of Salmonella and E. coli O157:H7 using the disc diffusion method. A total of 27 Salmonella and 20 E. coli O157:H7 isolates were recovered from 228 samples (200 cloacal swabs and 28 postmortem samples). All Salmonella isolates exhibited resistance to ampicillin, with high levels of resistance against sulfamethoxazole (85.1%), cefoxitin (85.1%), and tetracycline (77.8%). Similarly, E. coli O157:H7 isolates demonstrated complete resistance to ampicillin and high (90%) resistance to cefotaxime and tetracycline. Both pathogens showed significant sensitivity to gentamicin and azithromycin. Multidrug resistance (MDR) was identified in all Salmonella isolates and in 80% of the E. coli O157:H7 isolates. This finding reveals the presence of high level of AMR in Salmonella and E. coli O157:H7 isolates from poultry farms and that the poultry production in the study has undeniable contribution for the emergence and spread of AMR. This investigation underscore the importance of further investigations into the factors contributing to resistance, as well as the development of integrated AMR surveillance systems. Molecular investigations are recommended to confirm the mechanisms of resistance and to inform policy decisions and implement evidence based interventions.