Objective To investigate infection status and antimicrobial resistance mechanism of methicillin-resistant Staphylococcusaureus(MRSA),and provide reference for the rational antimicrobial use in clinic. Methods Staphylococcusaureus (SA)isolated from various specimens in Xuzhou area in 2012-2015 were collected,MR-SA strains were preliminarily screened by cefoxitin disk diffusion method,and confirmed by amplification of mecA gene,antimicrobial resistance of MRSA was determined by Kirby-Bauer method,minimal inhibitory concentration (MIC)was measured by E-test method,genotypes of staphylococcal chromosomal cassette mec(SCCmec)were de-termined by multiplex PCR. Results A 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 MR-SA 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 methicillin-sensitive Staphylococcusaureus(MSSA). MICs of vancomycin to MRSA in 2012-2015 were all 1.0μg/mL,MIC90 were all 1.5μg/mL,one MRSA isolate was with a vancomycin MIC of 2.0μg/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. Conclusion MRSA is seriously multidrug-resistant,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.%目的 了解耐甲氧西林金黄色葡萄球菌(MRSA)感染现状和耐药机制,为临床合理用药提供依据.方法 收集徐州地区2012—2015年各类标本中分离的金黄色葡萄球菌(SA),用头孢西丁纸片扩散法初筛MRSA菌株,扩增mecA基因进行确认,K-B法检测MRSA对药物的敏感性,E-test法测定万古霉素的最低抑菌浓度(MIC),采用多重PCR进行葡萄球菌染色体mec(SCCmec)基因分型.结果 2012—2015年210株SA共检出MRSA 116株,其中mecA基因阳性114株,MRSA总检出率为55.24%.MRSA对万古霉素、奎奴普丁/达福普汀、替考拉宁和利奈唑胺的敏感率均为100%,对氯霉素和呋喃妥因的耐药率最低,分别为15.52%、1.72%,MRSA对10种抗菌药物的耐药率>80%;MRSA对青霉素类、氨基糖苷类、红霉素、喹诺酮类、磺胺类、利福平、四环素、克林霉素的耐药率高于甲氧西林敏感金黄色葡萄球菌(MSSA).2012—2015年万古霉素对MRSA的MIC均为1.0μg/mL,MIC90均为1.5μg/mL,2015年发现1株MRSA的万古霉素MIC为2.0μg/mL.116株MRSA分型结果显示,SCCmecII型11株(9.48%),SCCmec III型85株(73.28%),SCCmec IV型4株(IVa和IVb型各2株,均为1.72%),未分型MRSA 16株(13.79%),未检出SCCmec I和V型.结论 MRSA呈严重的多重耐药,对万古霉素MIC无漂移,临床MRSA分离株以SCCmec III型为主,临床应采取感染控制措施,控制MRSA感染.
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