Antimicrobial Resistance of Escherichia coli and Salmonella isolated from Raw Retail Broiler Chicken Carcasses in Zambia

Abstract Background Antimicrobial resistance (AMR) of foodborne pathogens is of public health concern, especially in developing countries such as Zambia. This study was undertaken to determine the antimicrobial resistance profiles of Escherichia coli (E. coli) and Salmonella isolated from raw retail broiler chicken carcasses purchased from open and supermarkets in Zambia.Results A total of 189 E. coli and five Salmonella isolates were isolated. Identification and confirmation of the isolates were done using Analytical Profile Index (API 20E) (Biomerieux®) and 16S rRNA sequencing. Antimicrobial susceptibility tests (AST) were performed using the Kirby Bauer disk diffusion technique using a panel of 10 antibiotics. Multiplex PCR was used to determine the presence of three target genes encoding for resistance: tetA, Sul1 and blaCTX-M. WHONET 2018 software was used to analyse AST results. The E. coli isolates were mostly resistant to tetracycline (79.4%), ampicillin (51.9%), and trimethoprim/sulfamethoxazole (49.7%). Two of the five Salmonella isolates were resistant to at least one antibiotic. Forty- seven (45.2%) of the 104 isolates that were screened for the presence of the resistant genes possessed at least one of the targeted resistance genes.Conclusion This study has demonstrated the presence of AMR E. coli and Salmonella on raw retail broiler chicken carcasses from open and supermarkets, which is of public health concern.