Correlation between genotype and phenotypic categorization of staphylococci based on methicillin susceptibility and resistance.

Positive correlation between methicillin and oxacillin susceptibility test results and the detection of the mecA gene was observed for Staphylococcus aureus, S. epidermidis, and S. haemolyticus as well as among mecA(+) strains of other species of coagulase-negative staphylococci (CNS). However, at least 50% of the mecA-negative strains of these other species of CNS were falsely classified as methicillin and oxacillin resistant.