Abstract:ObjectiveTo investigate infection status and antimicrobial resistance mechanism of methicillinresistant Staphylococcus aureus(MRSA)，and provide reference for the rational antimicrobial use in clinic. MethodsStaphylococcus aureus (SA) isolated from various specimens in Xuzhou area in 2012-2015 were collected, MRSA strains were preliminarily screened by cefoxitin disk diffusion method, and confirmed by amplification of mecA gene, antimicrobial resistance of MRSA was determined by KirbyBauer method, minimal inhibitory concentration (MIC) was measured by Etest method, genotypes of staphylococcal chromosomal cassette mec(SCCmec) were determined by multiplex PCR. ResultsA total of 116 strains of MRSA were identified among 210 SA strains in 2012-2015，114 of which were positive for mecA gene, the total detection rate of MRSA was 55.24%. Susceptibility rates of MRSA to vancomycin， quinupristin/ dalfopristin, and linezolid were all 100%， resistance rates of MRSA to chloramphenicol and furantoin were both low, which were 15.52% and 1.72% respectively, resistance rates of MRSA to 10 kinds of antimicrobial agents were all>80%; resistance rates of MRSA to penicillins, aminoglycosides, macrolides, quinolones, sulfanilamide, rifampicin, tetracycline, and clindamycin were all higher than methicillinsensitive Staphylococcus aureus(MSSA). MICs of vancomycin to MRSA in 2012-2015 were all 1.0 μg/mL，MIC90 were all 1.5 μg/mL， one MRSA isolate was with a vancomycin MIC of 2.0 μg/mL in 2015. MRSA typing results of 116 MRSA isolates showed that SCCmec II, SCCmec III， and SCCmec IV accounted for 9.48%(n=11), 73.28%(n=85)，and 1.72%(Iva, n=2; IVb, n=2) respectively, 13.79%(n=16) of MRSA isolates were nontypeable, SCCmec I and SCCmec V type strains were not found. ConclusionMRSA is seriously multidrugresistant，the drift has not been discovered in MIC value of vancomycin against MRSA, the major SCCmec genotype of MRSA is SCCmec III， infection control measures should be taken to control MRSA infection.