Genotyping of staphylococcal cassette chromosome mec and antimicrobial resistance of 65 isolates of methicillin-resistant Staphylococcus aureus

Objective To investigate the genotype distribution characteristics of staphylococcal cassette chromosome mec(SCCmec) and antimicrobial resistance of methicillin-resistant Staphylococcus aureus(MRSA).Methods Multiplex polymerase chain reaction(PCR) was used to detect SCCmec genotype.Four antimicrobial resistant genes were amplified by traditional PCR.Antimicrobial susceptibility of 19 antibiotics was detected by disk diffusion method.Results The 60 isolates of MRSA were SCCmec Ⅲ,only 4 isolates were SCCmec Ⅳa,and 1 isolate had no genotype.All of the 65 isolates of MRSA were sensitive to linezolid,quinupristin/dalfopristin,vancomycin and teicoplanin,and were low resistant to chloramphenicol(4.62%).The positive rates of aac(6′)/aph(2′′),aph(3′)Ⅲ,tetM and ant(4′) were 93.85%,52.31%,92.31% and 9.23%.Conclusions The main SCCmec genotype of MRSA is SCCmecⅢ.MRSA has multiple resistances to commonly used antibiotics.There are high percentages of aminoglycoside and tetracycline.The multiplex PCR can be applied into genotyping study of MRSA SCCmec effectively.