Methicillin resistant Staphylococcus aureus among goat farms in Eastern province, Saudi Arabia: Prevalence and risk factors

A cross sectional study was conducted on 1010 goats from 25 flocks located in the eastern province, Saudi Arabia, to study the prevalence of methicillin resistant Staphylococcus aureus (MRSA) among goat farms. A total of 235 milk samples and 775 nasal swabs were collected for bacteriological investigation. Based on resistance to cefoxitin, 20 isolates were permissively identified as MRSA. PCR with specific primers was used to confirm MRSA. The prevalence of MRSA was 2%; with maximum prevalence in mastitic milk (9.2%) and swabs from animals showed respiratory signs (2.6%), while the lowest prevalence was identified in apparently normal milk (0.6). The standard disk diffusion test was used for in vitro evaluation of isolates resistance profile to 13 antimicrobial agents. Multidrug resistance (MDR) was detected in all MRSA and in 23.5% of methicillin sensitive Staphylococcus aureus (MSSA). Univariable association between the prevalence of MDR/MRSA strains and management practices indicated a higher prevalence with larger size flocks, where raising animals for both meat and milk production, and where antibiotics were used during the last 30 days, the latter was particularly pertinent to penicillin-streptomycin. Multivariable models indicated that larger flocks (200-400, and >400) were, respectively, 4 and 3.5 fold more likely to have MDR S. aureus compared to smaller flocks (<200).