ABSTRACT
In this study, the methicillin resistance of 112 Staphylococcus aureus and 93 coagulase negative Staphylococcus (CNS) strains, which were initially found methicillin resistant by routine disk diffusion method in our laboratory, have been searched by microdilution and oxacillin agar screen test and the results were compared with the results obtained by disk diffusion method. The presence of mecA gene was investigated by polymerase chain reaction in case of discordant results. All S. aureus strains (100%) and 69.9% (65/93) of CNS strains were found resistant to methicillin by three of the methods. Of CNS isolates, 28 strains which were found methicillin resistant by disk diffusion method, were found methicillin susceptible by oxacillin agar screen method, and 27 of these were detected as mecA positive. Our results indicated that, the three methods tested were reliable for the detection of methicillin resistance in S. aureus strains, but oxacillin agar screen revealed to be unsatisfactory for the detection of methicillin resistance in CNS.
