Antibiotic resistance and staphylococcal chromosomal cassette mec typing of methicillin-resistant Staphylococcus aureus isolates

OBJECTIVE To investigate antibiotic resistance and the distribution characteristics of staphylococcal chromosomal cassette mec(SCCmec) genotypes,and detect PVL gene of methicillin-resistant Staphylococcus aureus(MRSA) clinical isolates in our country.METHODS A total of 250 strains of MRSA were determined the minimal inhibitory concentrations(MIC) of antimicrobial agents by agar dilution method.SCCmec typing was conducted by multiplex PCR and PVL gene detected by simple PCR assay.RESULTS Totally 250 MRSA were detected SCCmec gene.SCCmec typing results showed that 30 strains was SCCmec type Ⅱ-dcs(12.0%),1 were SCCmec type Ⅱ subtype(0.4%),141 were SCCmec type Ⅲ(56.4%) with another 342bp(dcs) amplification bands,62 were SCCmec type Ⅲ(24.8%),7 were SCCmec type Ⅳ(2.8%),1 was SCCmec typeⅣa(0.4%),1 was SCCmec type Ⅴ(0.4%),and 7(10%) couldn′t be typed.No type Ⅰ was detected.Only 2 strains were PVL gene positive by a simple PCR assay.250 MRSA strains showed different resistant phenotypes to various antimicrobial agents.CONCLUSION The results show that the major SCCmec type of MRSA in China is SCCmec type Ⅲ,second is SCCmec type Ⅱ,only a few of SCCmec type Ⅳ and PVL gene positive.