Phenotypical and Genotypical Detection of Methicillin Resistance in Staphylococcus Aureus Isolates of Water Buffalo Milk and Dairy Product

The aim of our study was to investigate genotypic and phenotypic characteristics of methicillin resistance in Staphylococcus aureus isolates and as well as to determine MIC value. A total of 99 S. aureus isolates obtained from water buffalo milk and dairy product was used in the study. Methicillin resistance was measured using oxacillin (1μg) and cefoxitin (30μg) disc diffusion method according to Clinical and Laboratory Standards Institute (CLSI). Oxacillin and cefoxitin MIC value was determined by E test. Genotypic methicillin resistance was evaluated using Polymerase Chain Reaction (PCR) for the mecA gene. Out of 99 isolates, 14 (13.8%) were found to be methicillin resistant by oxacillin disc diffusion test, and nine (9%) were found to be resistant with cefoxitin by disc diffusion. Nine (9%) isolates were mecA gene positive by PCR.