Drug- and Multidrug-Resistance Pattern of Enterobacteriaceae Isolated from Droppings of Healthy Chickens on a Poultry Farm in Southwest Ethiopia

Background: In Ethiopia, the precise attribution of animals and their food products as the sources of resistant strains and the consequences of it on human health have not yet been seriously evaluated. Therefore, the aim of this study was to assess the drug- and multidrugresistance pattern of Enterobacteriaceae isolated from chicken droppings at Jimma University poultry farm, College of Agriculture and Veterinary Medicine, southwest of Ethiopia. Methods: A cross-sectional descriptive study was conducted from April, 2018 to June, 2018. A total of 140 fresh chicken dropping samples were collected and transported to Jimma University Medical Microbiology Laboratory for analysis. All samples were inoculated on MacConkey agar and xylose lysine deoxycholate agar. Gram stain and relevant biochemical tests were done for identification of isolates. Antimicrobial susceptibilities were tested by the Kirby-Bauer disk diffusion method. Results: Out of 140 chicken dropping samples, 61 (43.6%) showed bacterial growth. Of these, E. coli accounts for 39.0% followed by K. pneumoniae (22.0%), P. mirabilis (19.3%), and Salmonella species (17.7%). With regard to antibiotic resistance pattern, E. coli demonstrated a high rate of resistance against ampicillin (91.7%), tetracycline (75.0%), and trimethoprim-sulfamethoxazole (70.8%). K. pneumoniae showed a high resistance rate against ampicillin, trimethoprim-sulfamethoxazole, and tetracycline, with a resistance rate ranging from 76.9% to 85.6%. P. mirabilis and Salmonella spp. also showed high resistance against ampicillin, tetracycline, and trimethoprim-sulfamethoxazole with a resistance rate ranging from 72.7% to 83.3%. All isolates relatively showed lower resistance rates with a range of 20.8% to 41.7% against third-generation cephalosporins (ceftazidime and ceftriaxone), ciprofloxacin, and gentamicin. Totally, 32 (52.5%) of the isolates showed MDR against three or more antibiotics. Conclusion: Antibiotic resistant isolates against commonly prescribed single and multiple drugs were common. This highlights that chickens in the farm may serve as the reservoirs of antibacterial resistant bacteria that might infect humans through the food chain. Therefore, emphasis on the usage of antibiotics in chicken farms has to be considered.

Automated summary

This study evaluated the drug- and multidrug resistance patterns of Enterobacteriaceae isolated from chicken droppings at a university farm in southwest Ethiopia. The findings revealed common presence of E. coli, K. pneumoniae, P. mirabilis, and Salmonella species, with high resistance rates observed against certain antibiotics, highlighting the potential role of chickens in transmitting antibiotic-resistant bacteria to humans through the food chain.