Abstract

A cross sectional study to determine the prevalence and antimicrobial resistant profile of Salmonella isolates from 106 bulk milk of dairy cows was undertaken from December 2013 to April 2014 in supermarket, large and small holder’s dairy farms in Debre Zeit, Ethiopia. The bacteria was isolated and identified according to standard methods and sensitivity tests were done by the Kirby-Bauer disc diffusion method. The study revealed an overall prevalence of 23.6% (25/106). The occurrence of salmonella in large and small scale farm was 20.4% and 27.3% respectively. The isolated Salmonella spp. was resistant to at least two or more antimicrobials which were used in this study. A higher proportion of the isolates (96%) were resistant to ampicillin and the lowest resistance was recorded for streptomycin (8%). Assay of antimicrobial resistance revealed that 96% of Salmonella isolates were resistant to two or more of the nine antimicrobials tested whereas 4% of the isolate was sensitive. The most common resistance was to Ampicillin 24 (96%), oxytetracycline 21 (84%), amoxicillin 12 (48%), Chloramphenicol 10 (40%). A significant proportion has developed resistance for routinely prescribed antimicrobial drugs both in veterinary and public health sectors. This poses considerable health hazards to the consumers unless prudent antimicrobial usage, adequate heat treatment, improvement of standards of hygiene and development and enforcement of suitable legislation, which safeguard consumers, are urgently instituted.

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