تعيين استافيلوكوك اوريوس مقاوم به متي سيلين از طريق روشهاي فنوتيپيك

Determination of methicillin resistant Staphylococcus aureus via phenotypic methods and mecA gene study by multiplex PCR

Introduction: Methicillin resistant Staphylococcus aureus (MRSA) are one of the main reasons of nosocomial infection in the world and the treatment of this multidrug resistant bacteria is difficult thus making the identifying this bacteria is important. The purpose of this study is to determine the appropriate method for identification of methicillin resistant Staphylococcus aureus. Material and Methods: In this study, 86 types of Staphylococcus aureus separated from 86 patients were tested. The purpose was to determine their resistance to methicillin using phenotypic methods and detection of mecA gene. In this study, polymerase chain reaction (PCR) was considered as the standard method for identification of mecA gene and the two methods of phenotypic disc diffusion and Etest were compared with it. The PCR test was done as Multiplex PCR and in addition to the mec A gene, the 16SrRNA was also amplified and used as the internal control. Results: Forty-six strains showed resistance to methicillin and forty strains showed sensitivity to methicillin. The results from the E test showed a 100% compatibility with the PCR, but the similarity between the results from the oxacillin disc and those of PCR was only 43.8%. The results from the disc diffusion method for the other antibiotics used in this study were as follows: Methicillin resistant Staphylococcus aureus showed more resistance to erythromycin, ciprofloxacin, cloxacillin and cefotaxim in comparison with Methicillin sensitive Staphylococcus aureus (MSSA). Conclusion: The results show PCR and E test are similar in sensitivity and specificity, which are the best methods in methicillin resistant Staphylococcus aureus identification.