下呼吸道感染耐甲氧西林金黄色葡萄球菌分子生物学特征研究  

Molecular biological characteristics of methicillin-resistant Staphylococcus aureus causing lower respiratory tract infections

作　　者：虞亦鸣[1] 马红映[2] 王翎[1] 汪丽[3] 吕丹[2] 孙士芳[2] 舒丽华[2] 王卫华[3] 邓在春[2] 

机构地区：[1]苏州大学附属第一医院老年科,江苏苏州215006 [2]宁波大学医学院附属医院呼吸内科,浙江宁波315020 [3]宁波大学医学院附属医院微生物室,浙江宁波315020

出　　处：《中华医院感染学杂志》2015年第6期1211-1214,共4页Chinese Journal of Nosocomiology

基　　金：宁波市医学科技基金资助项目(2011B13)

摘　　要：目的分析下呼吸道感染耐甲氧西林金黄色葡萄球菌(MRSA)的临床及分子生物学特征,加深对MRSA耐药机制的理解。方法对医院2012年4-12月20例下呼吸道感染MRSA患者的临床特征及其MRSA耐药性进行分析;采用聚合酶链式反应(PCR)检测MRSA18种毒力基因与7种耐药基因。结果 20株MRSA均分离自医院住院患者的痰液标本,MRSA感染患者以老年人为主,分布科室主要为神经内、外科及ICU,基础疾病以脑血管意外、结构性肺病及脑外伤为主,分别占40.0%、25.0%和15.0%;20株MRSA对苯唑西林、青霉素、氨苄西林、头孢唑林的耐药率均为100.0%,对万古霉素为0;MRSA黏附毒力基因中fnbA、clfA、clfB、icaA及真性毒力基因hla、hld、pvl在20株菌株中表达阳性率100.0%;耐药相关基因中以mecA基因表达阳性率最高为95.0%,除第14株外其余均为黏附素基因与真性毒力基因加mecA基因阳性,并存在克隆传播。结论医院MRSA下呼吸道感染主要存在于有误吸风险及有结构性肺病的老年患者,MRSA携带毒力基因与病程、转归等的关系值得作进一步研究。OBJECTIVE To analyze the clinical and molecular biological characteristics of methicillin-resistant Staphylococcus aureus （MRSA ） causing lower respiratory tract infections so as to deepen the understanding of drug resistance mechanisms of the MRSA .METHODS The clinical characteristics of 20 patients with MRSA lower respiratory tract infections who were treated in the hospital from Apr 2012 to Dec 2012 were observed ,and the drug resistance of the MRSA strains was analyzed .The 18 virulence genes and 7 drug resistance genes in the MR-SA were detected by using polymerase-chain-reaction （PCR） .RESULTS Totally 20 strains of MRSA were isolated from the sputum specimens obtained from the hospitalized patients .The elderly people were the major population with MRSA infections ; the neurosurgery department , neurology department ,and ICU were the departments where the infections were prevalent .The cerebrovascular accident ,structural lung disease ,and traumatic brain in-jury were the major underlying diseases ,accounting for 40 .0% ,25 .0% ,and 15 .0% ,respectively .The drug re-sistance rates of the 20 strains of MRSA to oxacillin ,penicillin ,ampicillin ,and cefazolin were 100 .0% ,and the drug resistance rate to vancomycin was 0 .The positive rates of expression of the adhesion virulence genes （ fnbA, clfA, clfB,icaA） and the true virulence genes （hla ,hld ,pv l） in the 20 strains were 100 .0% .Among the drug resistance-related genes ,the positive rate of expression of mecA genes was the highest （95 .0% ） .All the strains were tested positive for the adhesion virulence genes ,true virulence genes ,and mecA gene except for strain NO . 14 ,which showed cloning spread .CONCLUSION The lower respiratory tract infection caused by the MRSA is prevalent in the elderly patients at risk of aspiration and structural lung disease .The relationship between the viru-lence genes in the MRSA and disease course and clinical outcomes needs to be further studied .

关 键 词：耐甲氧西林金黄色葡萄球菌 分子生物学 临床特征 

分 类 号：R378.11[医药卫生—病原生物学]