Detection of mecA gene in Staphylococcus aureus isolated from milk of industrial dairy farms in Ilam province

Staphylococcus aureus is one of the most important agents of mastitis in dairy cows. Mastitis poses many economic losses to animal husbandry particularly cattle industry. With regards to increasing rates of resistance of this bacterium to numerous antibiotics, efforts have been made to tackle staphylococcosis worldwide. The presence of mecA gene in Staphylococcus can result in methicillinresistant by decreasing affinity in binding of b-lactam antibacterial group in this bacterium. This study was aimed to evaluate the incidence of mecA gene as well as antibacterial resistance pattern in S. aurues strains isolated from industrial dairy cows suspected to mastitis in Ilam province. In this study, 208 specimens were collected from 7 industrial dairy farms in 2017, in which 42 (20.54%) bacteria identified as S. aureus by standard biochemical tests. Consequently, PCR of femA gene confirmed the results of phenotypic methods for 38 (91.56%) isolates. Of 38 S. aureus isolates, 22 (52.38%) had mecA genes. For evaluating antibiotic resistance and detecting of mecA gene the disc diffusion and PCR tests were performed, respectively. The highest resistance to antibiotics was penicillin (100%) and the lowest resistance was chloramphenicol (1.20%) (P<0.05). To the best of our knowledge, this is the first study to report the presence of mecA gene in this province. The results indicate that the prevalence of MRSA is too high in milk samples and this can be a health hazard to livestock. Therefore further studies on the typing of these isolates and conducting a comparative study with the isolates from hospitals are necessary.