Evaluation of methicillin resistance by cefoxitin disk diffusion and PBP2a latex agglutination test in mecA-positive Staphylococcus aureus, and comparison of mecA with femA, femB, femX positivities

Microbiol Res. 2009;164(4):400-3. doi: 10.1016/j.micres.2007.02.012. Epub 2007 May 3.

Abstract

Methicillin resistance in staphylococci is primarily due to the presence of a mecA gene which encodes the novel penicillin binding protein2a. Some chromosomal factors such as femA and femB also participate in the expression of methicillin resistance. This study was designed to detect methicillin resistance by cefoxitin disk diffusion and penicillin binding protein2a latex agglutination methods, and to compare mecA, femA, femB and femX gene positivities. A total of 60 MRSA isolates were included in the evaluation. PCR analysis showed that all isolates were positive for mecA and femA genes. Seven of these isolates tested negative by the latex agglutination test. Fifteen isolates were positive for femB and 28 isolates for femX gene. This study implicated that for the determination of methicillin resistance, latex agglutination test is the least reliable method when compared to PCR and cefoxitin disk diffusion test. femA gene shows more correlation than femB and femX with methicillin resistance.

MeSH terms

  • Bacterial Proteins / genetics*
  • Cefoxitin / pharmacology
  • Disk Diffusion Antimicrobial Tests / methods*
  • Genes, Bacterial
  • Latex Fixation Tests / methods*
  • Methicillin Resistance / genetics*
  • Penicillin-Binding Proteins / genetics
  • Penicillin-Binding Proteins / immunology
  • Staphylococcus aureus / drug effects*
  • Staphylococcus aureus / genetics

Substances

  • Bacterial Proteins
  • FemA protein, Bacteria
  • Penicillin-Binding Proteins
  • mecA protein, Staphylococcus aureus
  • Cefoxitin