Multiplex polymerase chain reaction for detection of genes for Staphylococcus aureus thermonuclease and methicillin resistance and correlation with oxacillin resistance

APMIS. 1993 Sep;101(9):681-8. doi: 10.1111/j.1699-0463.1993.tb00165.x.


A multiplex polymerase chain reaction (mPCR) was used for simultaneous amplification of the staphylococcal nuc gene, encoding the thermostable nuclease (TNase), and the mecA gene, encoding the penicillin-binding protein 2a which is associated with staphylococcal methicillin resistance. A total of 219 staphylococcal strains were tested and the mPCR data were compared with coagulase production and in vitro oxacillin susceptibility. The agreement was 100% for coagulase production and nuc amplification, and 97.7%, 96.8 and 97.3% for mecA amplification and oxacillin resistance tested with MIC determination, disk diffusion and agar screen methods, respectively. Discrepant results were due to non-S. aureus isolates with borderline MICs of oxacillin (1-8 micrograms/ml). In a pilot test the mPCR simultaneously amplified both genes of staphylococci in blood cultures. This mPCR is a rapid and reliable method for single-step identification of cultures of MRSA and may prove to be useful for direct application on clinical specimens.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • DNA Primers
  • DNA, Bacterial / analysis
  • DNA, Bacterial / isolation & purification
  • Drug Resistance, Microbial / genetics*
  • Electrophoresis, Agar Gel
  • Genes, Bacterial*
  • Methicillin Resistance / genetics*
  • Microbial Sensitivity Tests
  • Micrococcal Nuclease / genetics*
  • Oxacillin / toxicity*
  • Polymerase Chain Reaction / methods*
  • Staphylococcus / genetics
  • Staphylococcus aureus / drug effects
  • Staphylococcus aureus / enzymology*
  • Staphylococcus aureus / genetics*


  • DNA Primers
  • DNA, Bacterial
  • Micrococcal Nuclease
  • Oxacillin