耐甲氧西林金黄色葡萄球菌同源性分析及耐药性研究

目的对临床分离的耐甲氧西林金黄色葡萄球菌(MRSA)进行耐药情况和分子流行病学监测,探讨院内MRSA的流行趋势。方法收集我院2009年1月~2011年6月临床标本分离的MRSA菌株60株;采用Microscan WalkAway 40进行菌株鉴定,同时对所有金黄色葡萄球菌进行药物敏感性分析;采用脉冲场凝胶电泳技术对耐甲氧西林金黄色葡萄球菌进行分子分型。结果共收集60株MRSA菌株,其中17株被认为是可疑社区获得(CAMRSA),43株被认为是医院获得(HA-MRSA)。所有菌株均对万古霉素、替考拉宁、利奈唑胺、呋喃妥因和奎奴普丁/达福普汀敏感,未出现耐药菌株。CA-MRSA与HA-MRSA对左旋氧氟沙星和利福平的敏感性有明显差异。临床分离的MRSA菌株PFGE分型较为分散,共分为13种型别,每种型别的菌株数分别为2~6株不等,未出现大范围的院内流行克隆。结论本院收集的临床分离的MRSA菌株多重耐药性严重,其中CA-MRSA相对HAMRSA敏感性稍高。所有金黄色葡萄球菌未出现糖肽类抗菌药物耐药。MRSA菌株未出现大范围的院内流行株,但仍应加强院内感染流行控制。

Molecular epidemiology and drug-resistance mechanism of methicillin-resistant staphylococcus aureus

Objective To investigate the resistance status and clone dissemination of clinical methicillin-resistant staphylococcus aureus （MRSA） through molecular epidemiological surveillance. Methods Sixty clinical MRSA isolates from Jan 2009 to June 2011 in our hospital were collected. Species identification and antimicrobial susceptibility measuration were used by Microscan WalkAway 40 system. PFGE method was used in MRSA molecular typing. Results Seventeen isolates of 60 were considered as community-associated MRSA and the rest were hospital-associated MRSA. All strains were susceptible against vancomycin, teicoplanin, linezolid, nitrofurantoin and quinupristin/dalfopristin. In contrast with HA-MRSA, CA-MRSA was more susceptible against ciprofloxacin, rifampicin, gentamicin and levofloxacin. The PFGE of clinical MRSA strains determined 13 types, each type contains no more than 6 isolates. The dominant MRSA clone was inconspicuous in the hospital. Conclusion The muhidrug resistance of clinical MRSA strains was severe in our hospital. And the resistance of CA-MRSA was lower against HA-MRSA. All of the S. aureus strains were susceptible to glycopeptides. The clinical MRSA strains were not the hospital-dominant clone.