耐甲氧西林金黄色葡萄球菌染色体mec盒基因分型及耐药性分析

目的了解我院耐甲氧西林金黄色葡萄球菌(MRSA)感染的现状及耐药特征,为临床合理选用抗生素提供理论依据。方法收集我院2009年9月至2010年9月住院患者标本中分离到的临床资料完整的18株MRSA菌株作为研究对象,采用Kerby-Bauer纸片扩散法检测了18株MRSA对9种抗菌药物的敏感性水平;应用多重聚合酶链反应(PCR)方法对上述菌株进行了葡萄球菌染色体mec盒(SCCmec)分型。结果 18株MRSA对青霉素、苯唑西林、头孢西丁、环丙沙星和庆大霉素的耐药率均为100%,对克林霉素和红霉素的耐药率为89%,对利福平耐药率为56%、中敏率11%,无万古霉素耐药菌株;全部呈多重耐药,多重耐药主要表现为同时耐5种(22%)、6种(33%)及7种(44%)抗菌药物;18株MRSA的mecA基因阳性,其中9株(50%)携带有3种新的SCCmec型/亚型(New1～3)、6株(33%)携带ⅢB型SCCmec、3株(17%)为未定型菌株。结论 18株MRSA的SCCmec型别具有高度多态性,ⅢBSCCmec型是优势型别,未发现万古霉素耐药株。

Analysis of SCCmec genotyping and drug resistance of methicillin-resistant staphylococcus aureus

Objective： To investigate the current status and drug resistance of methieillin-resistant Staphylococ- cus aureus （MRSA） infeetion in our hospital, and to provide theory basis for rational selection of antibiotics in clinic. Methods Between September 2009 and September 2010, 18 MRSA strains isolated from the in-patients in our hos- pital with complete clinical data were collected and detected their sensitivity to 9 antibacterial agents using Kerby- Bauer. PCR method was then used to perform SCCmee typing on the strains mentioned above. Results The resistant rates of 18 MRSA strains to penicillin, oxacillin, cefoxitin, ciprofloxaein and gentamicin were 100%, those to elin- damycin and red neomycin resistance were 89%, those to rifampiein was 56%, and the mid-sensitivity rate to ri-fampiein was 11%, with no vaneomycin resistance strains. A total of 18 strains were found with muhidrug resistance, which was mainly manifested by resisting 5 （22%）, 6 （33%） and 7 （44%） different antibacterial agents. Eighteen MRSA strains had mecA genes with positive expression. Notably, 9 strains （50%） carried 3 novel SCCmec/subtype （Newl- 3）, 6 strains （33%） carried IIIB type SCCmec, and 3 strains （17%） were undefined strains. Conclusion Of 18 MRSA strains, the SCCmee types were highly polymorphic, and III B SCCmee types were the local advantage type. However, no vaneomycin resistance strain was found.