2.7. Detection of mecA Gene in Methicillin-Resistant S. aureus Isolates

Staphylococcus aureus isolates that were phenotypically confirmed as methicillin-resistant were further screened by PCR for the presence of the mecA gene. This gene encodes a modified penicillin-binding protein designated as PBP2a with reduced affinity for β-lactams. The amplification of the 533 bp fragment of the mecA gene was optimized under the following conditions: initial denaturation at 95°C for 5 min, 35 cycles of denaturation at 94°C for 1 min, annealing at 50°C for 1 min, extension at 72°C for 1 min with a final extension at 72°C for 5 min, and cooling to 4°C. Similarly, PCR products were separated electrophoretically, as described above.