Detection of methicillin-resistance gene in Staphylococcus epidermidis strains isolated from patients in Al-Zahra Hospital using polymerase chain reaction and minimum inhibitory concentration methods.

BACKGROUND

In recent years, antibiotic resistance of Staphylococcus epidermidis to methicillin has significantly increased, making it essential to study resistance to methicillin, which is a determining factor in the appropriate treatment pattern. The purpose of this study was to identify methicillin-resistant genes in S. epidermidis strains using polymerase chain reaction (PCR) and to determine their mean minimum inhibitory concentration (MIC) to methicillin using E-test method.

MATERIALS AND METHODS

MIC was determined on 146 samples of S. epidermidis using E-test method. Moreover, all samples were tested for the presence of mecA gene using PCR.

RESULTS

PCR test showed 75.34% of the samples to contain mecA gene. Methicillin resistance test was performed using E-test on all the samples, which showed resistance in different dilutions.

CONCLUSION

The frequency of mecA gene in S. epidermidis isolates was 75.34%. Among the various applied tests used for determining methicillin resistance, sensitivity and specificity of PCR were the highest and reached 100%. Sensitivity and specificity were found to be 95.3% and 94.7%, respectively, for phenotypic test (E-test) and 86.5% and 80.9%, respectively, for disk diffusion method. Based on the above results, it seems that resistance of S. epidermidis to methicillin is on the rise, and therefore more research is warranted.