Study On Staphylococcal Cassette Chromosome Mec Genotyping And Antimicrobial Resistance Of Methicilin-Resistant Staphylococcus Aureus

Objective:To investigate antimicrobial resistance of methicillin-resistant Staphylococcus aureus (MRSA) isolated from the clinical specimens, genotype characteristics of staphylococcal cassette chromosome mec (SCCmec), and expression of Panton-Valentine leucocidin(PVL) and toxic shock syndrome toxin (TSST-1) in three teaching hospital of Jinan., so that the result above will be get the message of the molecular epidemiologic characters of MRSA and beneficial to the control and prevention of MRSA infection.Methods:From Mary2009to January2011,61isolates of methicillin-resistant Staphylococcus aureus were collected from three teaching hospitals in Jinan.The drug-resistance of12kinds of antimicroibial agents (Oxacillin, Clindamycin,Erythromycin,Trimethoprim-Sulfamethoxazole,Vancomycin,teicoplanin,Linezolid, rifampicin, Levofloxacin, gentamicin, furantoin and fusidic acid)against of MRSA were detected by Kirby-baure(K-B) method.Their DNAs were extracted by gene extraction kit. Detect mecA、PVL and TSST-1gene by polymerase chain reaction(PCR). SCCmec typing of all clinical isolates of MRSA was performed by novel multiplex PCR assay.Results:(1)All strains of MRSA were resistant to Oxacillin, but the mecA-positive strains were59.(2) The resistance rates of59strains of MRSA to Erythromycin, Clindamycin, gentamicin, Levofloxacin and rifampicin were higher,respectively88.1%、88.1%、84.7%、89.8%、83.1%. The sensitive rates of59strains of MRSA to Trimethoprim-Sulfamethoxazole and fusidic acid were75.4%、89.08%.All trains were sensitive to Vancomycin, teicoplanin,Linezolid, and furantoin.(3) Among all MRSA isolates, SCCmec types were mainly SCCmecⅢ,accou-nted for86.4%.In this study, one strain was SCCmec Ⅱ,four were SCCmecIV,and three were untypeable type.(4) Two strains contained PVL gene and one strains contained TSST-1gene, which were SCCmecⅢ.The prevalence of PVL gene and TSST-1was respectively3.4%and1.96%.Conclusions:(1) This study demonstrated that MRSA isolates are resistant multidrug, but sensitive to vancomycin.(2) Among all MRSA isolates, SCCmec types were mainly SCCmecⅢ.account-ed for86.4%.In this study, one strain was SCCmec Ⅱ,four were SCCmecⅣ,and three were untypeable type.(3) Two strains contained PVL gene and one strains contained TSST-1gene,which were SCCmecⅢ.