Isolation Identification and Antimicrobial Susceptibility Pattern of Salmonella and S Aurous from Selected Dairy Farms in Beedle and Nekemte Districts Western Ethiopia

Abstract

Background: Bacterial diseases transmitted through food pose a serious threat to human and animal health. Salmonella and S. aurous are among the major foodborne pathogens. It is becoming a worldwide problem to date. In this regard, there is a lack of information among farms in western Ethiopia. Therefore, the study was conducted to isolate, identify, and assess the antimicrobial susceptibility profile of Salmonella and S. Aureus from Selected Dairy Farms in the study area. Methodology: A cross-sectional study was done from December 2018 to June 2019 on small scale dairy farms from Bedele and Nekemte town, Western Ethiopia with the objective of isolating and identifying Salmonella and S. Aureus from lactating cows, milkers’ and milking equipment at farms and to determine the antimicrobial susceptibility of the isolates. A total of 383 samples consisting cow milk, feces, cow nasal swab, milkers’ hand swab, milkers nasal swab, bucket swab, and floor swab were collected from 20 dairy farms. The samples were examined for the presence of Salmonella and S. Aureus following standard techniques and procedures. Agar disc diffusion method was used for the antimicrobial susceptibility testing. Results: The overall occurrence of Salmonella and S. Aureus was 2.35%and 2.35% respectively. Out of the 9 Salmonella isolates, 5(4.95%), 3(2.97%), and 1(5%) were isolated from udder milk, rectal feces and floor swab respectively. S. Aureus isolate was highest in udder milk 3(2.97%), followed by cow nasal swab 2(1.98%), feces 1(0.99%), bucket swab 1(5%), floor swab 1(5%) and milker’s nasal swab 1(5%). All salmonella isolates were 100% sensitive to nalidixic acid, however 55.55%, 22.22 %, and 11.11, respectively, were resistant to cefoxitin, tetracycline, and gentamycin. The antibiotic susceptibility profiles of the S. Aureus showed that 55.55% and 11.11% were resistant to Penicillin G and Erythromycin, respectively and were 100% sensitive to cefoxitin, nitrofurantoin, and gentamicin. Conclusion: Even if the current study shows lower prevalence, lower antimicrobial resistance and higher susceptibility for most antimicrobials, stringent control measures, such as treatment of positive cases with effective medications and preventative measures including strict hygiene standards, such as cleaning of the floor, pens, and milking equipment, as well as adequate hand washing throughout the milking process, should be adopted.