Prevalence and antimicrobial resistance profiles of Salmonella species and Escherichia coli isolates from poultry feeds in Ruiru Sub-County, Kenya.

Objectives: Contaminated poultry feeds can be a major source of E. coli and Salmonella infections in poultry. This study aimed at determining microbial load, prevalence and antimicrobial resistance profiles of Salmonella sp. and E. coli and associated resistance genes among isolates from poultry feeds.

Results: A total of 150 samples of different poultry feed types were randomly collected from selected sites within Ruiru Sub-County. The microbial load was determined, Salmonella sp. and Escherichia coli were isolated and antimicrobial susceptibility test carried out. Antimicrobial resistance genes were also screened among the resistant isolates. Out of analyzed samples, 58% and 28% contained Escherichia coli and Salmonella sp. respectively. Bacterial load ranged between 3.1 × 10 and 3.0 × 10 cfu/g. Highest resistance was against ampicillin (41%) for Salmonella sp. and (62%) for E. coli isolates. Ampicillin resistant isolates carried TEM and SHV genes. In addition, strB and Dfr resistance genes associated with streptomycin and cotri-moxazole were detected. All the isolates were susceptible to chloramphenicol and ciprofloxacin. The study reveals high bacterial contamination, presence of beta-lactamase, aminoglycoside and sulphonamide resistance genes across isolates from poultry feeds. Therefore, contaminated poultry feeds with bacteria are likely to lead to increase in antimicrobial resistant strains across the community.