Comparison of polymerase chain reaction and conventional methods in detecting methicillin-resistant Staphylococcus aureus

Abstract

Background: Accurate and rapid detection of methicillin-resistant

Staphylococcus aureus is very important in a clinical laboratory

setting to avoid treatment failure. Conventional methods were compared against the gold standard polymerase chain reaction

(PCR) technique to determine the best combination of the routine procedures.

Methodology: Methicillin resistance was investigated in 416 clinical

Staphylococcus aureus isolates by PCR, oxacillin agar

screening (OAS), oxacillin disk diffusion (ODD) and cefoxitin disk diffusion (CDD) methods.

Results: Two hundred and ten (51%) out of 416

S. aureus strains were found to be mecA-positive by PCR. Sensitivity and

specificity of the ODD, CDD and OAS methods were detected as follows: 100% and 89%, 99.50% and 100%, and 99.50% and

100%, respectively

.

Conclusion: Combining the ODD and CDD methods could be a good choice for detecting methicillin resistance in

S. aureus

strains where mecA PCR cannot be performed.

Key Words

: Methicillin-resistant Staphylococcus aureus (MRSA), polymerase chain reaction (PCR), oxacillin disk diffusion,

cefoxitin disk diffusion, oxacillin agar screening.