پزشکی بالینی ابن سینا (Sep 2001)
Detection of Resistant Gene to Methicillin ( mec-A)in Purulent Infections Related to Staphylococcus Using PCR
Abstract
The emergence of Staphylococcus strains resistant to methicillin occurred shortly after the introduction of methicillin into clinical use . Resistance to methicillin in clinical isolates of Staphylococci has been explained by the production of a characteristic penicillin-binding protein (PBP) , designated PBP2a, that has a decreased binding affinity for b-lactam antibiotics, the gene mec-A encoding PBP2a was cloned and is distributed among methicillin- resistant but not methicillin-susceptible populations of S. aureus. Recently, high prevalence of methicillin resistance has been noticed in the clinical isolates of coagulase-negative Staphylococci (CNS) which, besides MRSA( Methicillin- Resistant -Staphylococcus aureus), also have been recognized as important nosocomial pathogens . Detection of the mec-A using PCR may provide a sensitive method for identifying methicillin resistant Staphylococci . In this study, overall 268 wound swabs in which 107 cases (40%) were Staphylococcus aureus and 10 cases (3.7%) were coagulase negative Staphylococcus and the rest of them were other microorganisms were examined . After the extraction of DNA , PCR was carried out using specific primers. The results indicated that the mec-A was present in 24 cases ( 9% ) . In 8 cases (34%) Staphylococcus aureus ,3 cases (12%) coagulase negative Staphylococci , the others were related to another microorgamisms that probably were contaminated by Staphylococcus species.
