【作者】 刘旻；

【导师】 熊自忠； 许夕海； 李鸿宾；

【作者基本信息】 安徽医科大学 ， 内科学， 2008， 硕士

【摘要】 耐甲氧西林金黄色葡萄球菌(MRSA)目前成为医院感染的重要病原菌之一,很多文献报道其发生率持续上升。而凝固酶阴性的耐甲氧西林表皮葡萄球菌(MRSE)的发生率则更高,有报道其发生率为80%或以上。MRSE不仅对甲氧西林耐药,还对其他多种抗菌药物耐药,具耐多药特征,已是临床抗感染化疗的难题之一。本研究对安徽省部分医院临床分离的表皮葡萄球菌进行检测,检出其中的耐甲氧西林表皮葡萄球菌,了解本地区MRSE的检出率,比较两种检测方法,对检出的MRSE进行耐药性检测,为临床防治MRSE感染及合理使用抗生素提供实验依据;并对MRSE进行分子生物学研究,这对于细菌性传染病的监测,传染源追踪、传播途径调查和识别等爆发调查有着非常重要的意义。目的了解本地区MRSE的检出率,比较两种检测方法;对检出的MRSE进行耐药性检测,了解本地MRSE耐药的特点;并对MRSE菌株的同源性进行研究。为临床合理用药和耐药菌的防治提供参考依据。方法采用头孢西丁纸片扩散法及mecA基因PCR法检测出MRSE菌株,并对两种检测方法加以比较。以PCR方法检测出mecA基因作为检测MRSE菌株的金标准,了解头孢西丁纸片扩散法检测MRSE菌株的灵敏度及特异度。采用琼脂稀释法测定分离出的表皮葡萄球菌对17种常用抗生素的最低抑菌浓度(MIC)。以肠道细菌基因间重复一致序列(enterobacterial repetitive integenic consensus,ERIC)为引物结合位点,PCR扩增MRSE基因,并进行同源性分析。结果128株临床分离表皮葡萄球菌中,用头孢西丁纸片法及PCR法对MRSE检出率分别为79.69%(102/128)和85.16%(109/128),两种方法对MRSE检出率差异无统计学意义。以PCR法检出mecA基因作为判断MRSE的金标准,头孢西丁纸片法灵敏度为88.07%、特异度为68.42%、符合率为88.16%。MRSE对多种抗菌药物耐药显著;除对β-内酰胺类明显耐药外,对红霉素和克林霉素的耐药率均高达98.17%,对氟喹诺酮类(左氧氟沙星和环丙沙星)的耐药率亦超过80%。MRSE对万古霉素、替考拉宁100%敏感,未发现耐药菌株。利用ERIC-PCR检测MRSE的同源性,结果显示部分MRSE菌株间谱型相同。结论头孢西丁纸片法是筛选和确认MRSE菌株的一种可靠、简便的方法。MRSE为多重耐药菌株,耐药形势严峻,部分菌株间存在克隆传播现象,临床必须加强细菌耐药性监测。更多还原

【Abstract】 Along with the wide application antimicrobial agents,staphylococci have become an important source of nosocomial infection.The resistance of methicillin resistant staphylococcus epidermidis(MRSE) has increased even more than the resistance rate of MRSA.And caused more and more difficulities for clinical therapy.We evaluated the two methods for detection of MRSE,and analysis the resistance of staphylococcus epidemidis isolated from 20 hospitals in Anhui from January to December in 2005.Based on the study of molecular biological mechanism and molecular epidemiology,test the gene of MRSE.The results of present study may contribute to clinical therapy and molecular epidemiology of MRSE.Objective:Investigating the resistant of MRSE,evaluating the two methods for detetion of MRSE.Investigating the homology in MRSE isolates.Methods:MRSE were detected by cefoxitin disk diffusion,as well as PCR amplification for the mecA gene,respectively.128 strains of S.epidermidis isolates were tested for minimus inhibitory concentration(MIC) to 17 kinds of antimicrobial agents with agar dilution method.Taking enterobacterial repetitive integenic consensus(ERIC) as primer binding site,analysis the homology in MRSE by PCR.Results:The rates of MRSE detected by cefoxitin disk diffusion as well as PCR amplification for the mecA gene were79.69%and 85.16%,respectively,and the result of two groups had no difference(P＞0.05).Cefoxitin disk diffusion method of the specificity and sensitivity were higher enough to replace mecA PCR in clinical work.Except penicillin-G,resistance rate of MRSE to erythromycin and clindamycin were high too.And all strains were sensitive to vancomycin.Some isolates of MRSE have same fingerprint of genotype.Conclusions:Cefoxitin disk diffusion method can be used reliably in detecting and conforming MRSE.Resistance in MRSE was getting more and more serious,and some MRSE strains had clonal dissemination.So detection and surveillance of them should be emphasized.更多还原