Prevalence, Associated Risk Factors and Antimicrobial Susceptibility of Staphylococcus aureus Isolated from Bovine Mastitic Milk in and Around Asella Town, Ethiopia

A cross sectional study was carried out from November 2016 to April 2017 in and around Asella town to determine the prevalence, associated risk factors and antimicrobial susceptibility of Staphylococcus aureus in Bovine mastitic milk. A total of 384 lactating dairy cows were screened for mastitis based on clinical examinations and California Mastitis Test (CMT). Out of 230 lactating crossbred cows with either clinical or subclinical mastitis examined for the involvement of Staphylococcus aureus. Staphylococcus aureus was isolated at a rate of 47.2% and 42.9% of the subclinical and clinical cases, respectively. The overall prevalence of Staphylococcus aureus scored in this study was 46.5%. Among the risk factors considered, Age, parity and lactation stage were found significantly associated with the occurrence of S. aureus in mastitic milk (p<0.05). The current study revealed that S. aureus has avery low susceptibility to penicillinG (0%), followed by tetracycline (14.2%). However, these randomly selected isolates were found to be susceptible (100%) to Kanamycin. Proper prevention and regular antimicrobial sensitivity testing help to select effective antibiotics and ultimately reduce the development of resistance towards commonly used antibiotics.