CAJ | 학술논문

目的研究耐甲氧西林凝固酶阴性葡萄球菌(MRCoNS)临床分离株对利奈唑胺的耐药机制及分子流行病学.方法 2011年3-8月我院分离到17株对利奈唑胺耐药的MRCoNS,包括10株头状葡萄球菌、4株科氏葡萄球菌、2株溶血葡萄球菌和1株松鼠葡萄球菌.用E-test法测定抗生素对细菌的最低抑菌浓度(MIC)；脉冲场凝胶电泳(PFGE)分析菌株之间的同源性；PCR扩增和序列分析研究细菌对利奈唑胺耐药的分子机制.结果 9株利奈唑胺MIC值为＞256 μg/ml的头状葡萄球菌为同一克隆株,MIC值为4μg/ml的另1株头状葡萄球菌为密切相关菌株.4株利奈唑胺MIC值为＞256 μg/ml的科氏葡萄球菌为同一克隆株.松鼠葡萄球菌利奈唑胺MIC值为64 μg/ml,2株溶血葡萄球菌分别为4 μg/ml和6μ/ml.对23S rRNA基因第5功能区和cfr基因进行PCR扩增和测序发现,9株利奈唑胺MIC值为＞256 μg/ml的头状葡萄球菌的23S rRNA基因第5功能区存在常见G2576T突变和一个未报道过的C2104T突变；松鼠葡萄球菌存在G2576T突变；除松鼠葡萄球菌外,其余16株菌株均携带cfr基因.结论首次报道在国内分离到利奈唑胺耐药的葡萄球菌临床菌株.MRCoNS对利奈唑胺耐药与23S rRNA基因第5功能区碱基突变和携带cfr基因相关.利奈唑胺耐药MRCoNS在我院有克隆传播现象.
목적 연구내갑양서림응고매음성포도구균(MRCoNS)림상분리주대리내서알적내약궤제급분자류행병학.방법 2011년3-8월아원분리도17주대리내서알내약적MRCoNS,포괄10주두상포도구균、4주과씨포도구균、2주용혈포도구균화1주송서포도구균.용E-test법측정항생소대세균적최저억균농도(MIC)；맥충장응효전영(PFGE)분석균주지간적동원성；PCR확증화서렬분석연구세균대리내서알내약적분자궤제.결과 9주리내서알MIC치위＞256 μg/ml적두상포도구균위동일극륭주,MIC치위4μg/ml적령1주두상포도구균위밀절상관균주.4주리내서알MIC치위＞256 μg/ml적과씨포도구균위동일극륭주.송서포도구균리내서알MIC치위64 μg/ml,2주용혈포도구균분별위4 μg/ml화6μ/ml.대23S rRNA기인제5공능구화cfr기인진행PCR확증화측서발현,9주리내서알MIC치위＞256 μg/ml적두상포도구균적23S rRNA기인제5공능구존재상견G2576T돌변화일개미보도과적C2104T돌변；송서포도구균존재G2576T돌변；제송서포도구균외,기여16주균주균휴대cfr기인.결론 수차보도재국내분리도리내서알내약적포도구균림상균주.MRCoNS대리내서알내약여23S rRNA기인제5공능구감기돌변화휴대cfr기인상관.리내서알내약MRCoNS재아원유극륭전파현상.
Objective To investigate the linezolid resistance mechanisms and molecular epidemiology of clinical isolates of methicillin-resistant coagulase-negative staphylococci (MRCoNS).Methods Seventeen MRCoNS,including 10 S.capitis,4 S.cohnii,2 S.haemolyticus,and 1 S.sciuri with various levels of linezolid resistance were isolated from intensive care units in our hospital from March to August 2011. Minimal inhibitory concentration (MIC) was determined by E-test method. Pulsed-field gel electrophoresis was performed to analyze the molecular epidemiology.PCRs and DNA sequencing were preformed to investigate the mechanisms of linezolid resistance in MRCoNS.Results Nine S.capitis with linezolid MIC of ＞256 μg/ml were indistinguishable,and another S.capitis with linezolid MIC of 4 μg/ml was closely related.Four S.cohnii with linezolid MIC of ＞256 μg/ml were belonged to the same clonal strain.MIC of linezolid for S.sciuri was 64 μg/ml,and were 4 μg/ml and 6 μg/ml for 2 S.haemolyticus,respectively.A commom G2576T mutation and a novel C2104T mutation were identified in 9 S.capitis with linezolid MIC of ＞256 μg/ml by DNA sequence analysis of domain V of the 23S rRNA gene.cfr gene was deteeted in all staphylococci except a S.sciuri whose 23S rRNA gene contained the G2576T mutation.Conclusion It is the first report of linezolid-resistant clinical isolates of staphylococci in China.Linezolid resistance in MRCoNS is related to the presence of DNA mutation in domain V of the 23S rRNA gene and cfr gene.It's a clonally dissemination of linezolid-resistant MRCoNS in intensive care units of our hospital.