医院感染耐甲氧西林金黄色葡萄球菌耐药性与SCCmec分型及同源性研究

目的 研究医院耐甲氧西林金黄色葡萄球菌(MRSA)的耐药性及分子流行病学特点,为预防和控制医院感染提供参考.方法 采用药敏纸片法(K-B法)、SCCmec分型及葡萄球菌A蛋白(spa)分型技术,2009年3-4月对烧伤科、ICU、呼吸内科、急诊科、血液内科、儿童急救科和儿童呼吸科住院患者、医务人员及环境分离的MRSA,进行了药敏试验和同源性分析,并检测其杀白细胞毒素(pvl)基因.结果 从1352份标本中分离出108株金黄色葡萄球菌,MRSA为54株占50.0％,主要分离于烧伤科42株占77.8％；分离的临床菌株总体耐药率较高,除万古霉索外耐药率均＞50.0％,未发现万古霉素耐药株；SCCmec分型结果显示,54株MRSA以Ⅲ型为主占68.5％,pvl基因均为阴性；进行spa分型研究的23株MRSA中,22株为t030,1株为t2270,呈现高度的克隆一致性.结论 医护人员MRSA带菌率较高,部分医务人员、住院患者和环境中分离的MRSA有较高的同源性,存在人与人和人与环境之间的MRSA传播.

Drug resistance of methicillin-resisitant Staphylococcus aureus causing hospital infections,genotyping of SCCmec and homology

OBJECTIVE To study the drug resistance and characteristics of molecular epidemiology of methicillin-resistant Staphylococcus aureus(MRSA)and provide scientific evidence for preventing and controlling the spread of MRSA.METHODS Disk diffusion method,SCCmec multi-PCR and spa typing method were adopted to identify phenotype of the MRSA strains isolated from hospitalized patients,hospital environment and medical staff in department of burn,ICU,department of respiratory diseases,department of emergency,department of hematology,children’s department of emergency and children’s department of respiratory diseases between Mar.and Apr.2009.The drug susceptibility testing and analysis of homology were performed.The panton-valentine leukocidin gene(pvl) was detected.RESULTS A total of 108 strains of S.aureus were isolated from 1352 specimens.There were 54(50.0%) strains of MRSA,mainly isolated from department of burn(42 strains),accounting for 77.8%;the resistance rates of MRSA to all commonly used antibiotics except vancomycin were higher than 50.0%.There were no VRSA isolates found.SCCmec typing result showed that most MRSA isolates were type III(68.5%).All isolates were negative for pvl gene;Of the 23 strains of MRSA for which spa typing was performed,22 strains were typed as t030,and 1 strain was typed as t2270,showing high clonal consistency.CONCLUSION The MRSA carrying rate of medical workers is high.The MRSA strains from some medical workers,inpatients and surroundings are highly homological,and the spread between person and person and the spread between person and environment exist in hospital.