MULTIPLEX POLYMERASE CHAIN-REACTION FOR DETECTION OF GENES FOR STAPHYLOCOCCUS-AUREUS THERMONUCLEASE AND METHICILLIN RESISTANCE AND CORRELATION WITH OXACILLIN RESISTANCE

A multiplex polymerase chain reaction (mPCR) was used for simultaneous amplification of the staphylococcal nuc gene, encoding the thermostab le nuclease (TNase), and the mecA gene, encoding the penicillin-bindin g protein 2a which is associated with staphyloccal methicillin resista nce. A total of 219 staphylococcal strains were tested and the mPCR da ta were compared with coagulase production and in vitro oxacillin susc petibility. The agreement was 100% for coagulase production and nuc am plification, and 97.7%, 96.8 and 97.3% for mecA amplication and oxacil lin resistance tested with MIC determination, disk diffusion and agar screen methods, respectively. Discrepant results were due to non-S. au reus isolates with borderline MICs of oxacillin (1 -8 mug/ml). In a pi lot test the mPCR simultaneously amplified both genes of staphylococci in blood cultures. This mPCR is a rapid and reliable method for singl e-step identification of cultures of MRSA and may prove to be useful f or direct application on clinical specimens.