社区获得性金黄色葡萄球菌ST398克隆株与医院获得性ST5、ST239克隆株毒力及耐药特征  

Community-associated Staphylococcus aureus ST398 isolates compared with hospital-associated ST5 and ST239 isolates in terms of virulence and antimicrobial resistance

作　　者：朱元军[1] 李天铭[1] 王亚楠[1] 洪旭芬[1] 李敏[1] 

机构地区：[1]复旦大学附属华山医院检验医学科,上海200040

出　　处：《中国感染与化疗杂志》2015年第4期295-301,共7页Chinese Journal of Infection and Chemotherapy

基　　金：国家自然科学基金(81322025;81171623;81371875);上海市曙光人才计划(12SG03);上海市科委(14140901000)

摘　　要：目的研究社区获得性金黄色葡萄球菌(金葡菌)ST398克隆株(CA-ST398)与医院获得性金葡菌流行ST5、ST239克隆株(HA-ST5,HA-ST239)在毒力基因携带及表达、耐药特征上的异同。方法通过多位点保守基因测序分析方法对上海华山医院门诊和住院患者分离的金葡菌进行克隆分型。用聚合酶链反应(PCR)方法对随机选取的56株CA-ST398、50株HAST5和50株HA-ST239毒力基因携带情况进行分析,随后采用实时荧光定量(RT)-PCR方法检测3个黏附相关基因(sdrC、fnbA、clfA)、1个定植相关基因(icaA)、2个外毒素基因(hla、psm)、1个调控因子(RNAⅢ)的表达情况。采用纸片法和微量肉汤稀释法对克隆株进行药物敏感性检测,采用PCR方法确定甲氧西林耐药金葡萄(MRSA)SCCmec基因分型。结果CA-ST398克隆株通常引起皮肤软组织感染(60.7%),而HA-ST239(72.0%)和HA-ST5克隆株(64.0%)通常引起呼吸道感染。与医院获得性金葡菌相比,CA-ST398克隆株sdrC、sdrE、pvl基因的携带率较高(P<0.01),sea、sec、see、seg、sei、sek、sel、sem、sen、seo、sep、seq、tst、sdrD、sasX、bsaA、lukE基因的携带率较低(P<0.05)。黏附相关基因sdrC、fnbA和clfA基因表达HA克隆株高于CA-ST398克隆株(P<0.05);外毒素基因hla、psm及调控因子RNAⅢ表达CA-ST398高于HA克隆株(P<0.01)。HA-ST239和HA-ST5克隆株对庆大霉素、左氧氟沙星、头孢西丁、头孢唑林的耐药率高于CA-ST398克隆株(P<0.001)。12.5%(7/56)CA-ST398为MRSA,100%(50/50)HA-ST239、94.0%HA-ST5(47/50)克隆株为MRSA。CA-ST398主要携带SCCmecⅤ(3.6%,2/56),HA-ST239主要携带SCCmecⅢ(92.0%,46/50),HA-ST5主要携带SCCmecⅡ(90.0%,45/50)。结论 CA-ST398、HA-ST239和HA-ST5致病的差异可能与不同致病因子表达差异有关。HA-ST239和HA-ST5在医院环境中的持续定植感染可能与黏附相关因子sdrC、fnbA和clfA高表达有关。CA-ST398的高毒力可能与外分泌型毒素α溶血素(hla编码)、酚可溶性蛋白(psm编�Objective This study was to compare the virulence and antimicrobial resistance profile between communityassociated （CA） ST398 Staphylococcus aureus isolates and hospital-associated （HA） ST5 and ST239 isolates. Methods A total of 56 CA-ST398 strains isolated from outpatients, and 50 strains each of HA-ST5 and HA-ST239 from inpatients in Huashan Hospital were screened out by multilocus sequence typing. The S. aureus strains were characterized by molecular analysis of virulence genes, SCCmec typing and antimicrobial susceptibility. The expression of 7 virulence genes （sdrC, fnbA, clfA, icaA, hla, psm, and RNA lid was analyzed by quantitative reverse transcription polymerase chain reaction. Results Most CA-ST398 strains （ 60. 7%） were from skin and soft tissue infection, while HA-ST239 （72. 0%） and ST5 （64. 0%） strains were mostly isolated from respiratory tract infection. Compared with HA isolates, the toxin genes sdrC, sdrE, and pvl were more prevalent （P〈0.01）, while sea, sec, see, seg, sei, sek, sel, sere, sen, seo, sep, seq, tst, sdrD, sasX, bsaA, and luke genes were less prevalent （P〈0. 05） in CA-ST398 isolates. The expression level of sdrC, fnbA, and clfA was lower, while the expression level of hla, psm, RNA III was higher in CA ST398 isolates compared with that in HA isolates. HA-ST239 and HAST5 isolates showed more resistant to gentamicin, levofloxacin, cefoxitin, cefazolin than CA-ST398 isolates. The prevalence of methieillin-resistant S. aureus （MRSA） was 12. 5% （7/56） in CA-ST398 isolates, 100% in HA-ST239 and 94. 0G in HA-ST5 isolates. SCCmec genotyping showed the most prevalent type was SCCmec V in CA MRSA ST398 （3. 6%）, SCCrnec III in HA-ST239（92. 0%）, and SCCmec Ⅲ in HA-ST5 （90. 0%） strains. Conclusions The difference of pathogenicity between CA-ST398 and HA-ST239, HA-ST5 S. aureus strains may result from different expression levels of virulence genes. High expression of sdrC, fnbA and clfA may contribute to long-term colonization of HA S. aureu

关 键 词：金黄色葡萄球菌 医院获得性克隆株ST239 ST5 社区获得性克隆株ST398 毒力基因 耐药性 

分 类 号：R440[医药卫生—诊断学]