Prevalence and susceptibility assay of staphylococcus aureus isolated from bovine mastitis in dairy farms of Jimma town, South West Ethiopia

Abstract

Cross sectional experimental study was conducted to assess the prevalence and susceptibility pattern of Staphylococcus aureus isolated from bovine mastitis to commonly used antibacterial agents in Jimma town dairy farms, South West Ethiopia from January-July, 2010. Milk samples were collected aseptically and California Mastitis Test (CMT) was carried out to identify subclinical mastitis from dairy cows. All CMT high scored and clinically positive samples were investigated microbiologically. Rate of isolation of Staphylococcus aureus was determined and susceptibility of 11 antibiotics against 5. aureus was evaluated using the Kirby-Bauer disc diffusion method and the result was expressed as sensitive, intermediate and resistant. From total of 218 milk samples collected, 164 CMT high score milk samples were cultured of which 86 (52.4%) of pure strains of 5. aureus were isolated. Out of 86 pure isolates of 5. aureus resistance was detected for Penicillin (87.2%), Nalidixic acid (92%), Amoxicillin (46%), Chloramphenicol (16%), Clindamycin (4%) and Vancomycin (3%). The study also revealed that S. aureus was found to be sensitive for Norfloxacilin, Gentamycin, Tetracycline and Bacitracin. The present finding indicates that these isolates exhibited the highest degree of resistance to Nalidicic Acid, Penicillin, Amoxicillin and Chloramphenicol of among the tested anti microbial agents in comparison to previous studies reported. Furthermore, resistance follow-up, appropriate selection and use of antibiotic is recommended in the treatment of mastitis. © Medwell Journals, 2011.