Staphylococcal chromosome cassette typing in MRSA by multiplex PCR

ObjectiveTo identify the genotypes of staphylococcal chromosome cassette mec(SCCmec) in the isolates of methicillin-resistant Staphylococcus aureus(MRSA) from Shanghai No.6 People′s Hospital.MethodsMRSA(n=125) were isolated from various specimens from Feb.2006 to Jul.2006.The genotypes and subgenotypes of SCCmec were identified by multiplex PCR.PVL genes were detected by PCR.The antimicrobial susceptibility of MRSA was tested by disk diffusion technique.ResultsAll of the 125 isolates were positive for mecA gene.SCCmecⅡ was identified in only one isolate and SCCmecⅣ in 3 isolates.One isolate was nontypable.The other MRSA isolates were SCCmecⅢ genotype.PVL gene was not identified in these MRSA strains.The isolates showing SCCmecⅡ or SCCmecⅢ were multi-resistant to antibiotics.The isolates with SCCmecⅣ were susceptible to all antibiotics except β-lactams.ConclusionsSCCmec Ⅲ is the major SCCmec genotype of MRSA in our hospital.SCCmecⅣ but not PVL gene was identified in community-acquired methicillin-resistant Staphylococcus aureus(CA-MRSA).The isolates with SCCmecⅡ or SCCmecⅢ are multi-resistant to antibiotics.