ردیابی ژن ایجاد مقاومت نسبت به متی سیلین (mec-A) در عفونتهای چرکی ناشی از استافیلوکوک بوسیله PCR

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.