RAPID GENOTYPIC CONFIRMATION OF METHICILLIN RESISTANCE

Detection of phenotypic methicillin resistance in Staphylococcus aureu s clinical strains by conventional disk diffusion testing is fraught w ith problems. We used gene amplification of the mecA locus by polymera se chain reaction (PCR), in conjunction with a capillary/air thermal c ycler, to overcome both the inaccuracy of phenotypic methods and the l engthy processing times required for previous genotypic methods. The r apid PCR method correctly identified methicillin resistance in a conse cutive series of 30 S. aureus isolates when compared with routine and reference phenotypic methods. The shorter processing time and smaller reagent volumes required for the air thermal cycler make same-day dete rmination of methicillin resistance in clinical isolates feasible for diagnostic laboratories.