大肠埃希菌耐药性及其基因同源性分析

目的 研究临床分离的大肠埃希菌对常用抗生索的耐药性及其基因分型，了解其耐药性趋势与传播流行情况，为临床合理治疗大肠埃希菌引起的感染提供参考依据。方法 采用常规鉴定技术鉴定细菌；采用K—B纸片扩散法测定77株大肠埃希菌对19种药物的耐药性；K—B法鉴定产超广谱β-内酰胺酶（ESBLs）；通过脉冲场凝胶电泳（PFGE）法对其进行基因分型以确定菌株之间的亲缘关系；FINGERPRINT Ⅱ软件进行细菌基因指纹图谱分析。结果 大肠埃希菌对青霉素类、喹诺酮类药物和氨曲南的耐药性明显增高，亚胺培南和美罗培南是大肠埃希菌感染患者的首选药物；经ESBLs确证试验，ESBLs阳性率为28．60％（22／77）；产ESBLs大肠埃希菌经PFGE指纹图谱分析，除第62株和第70株相似性系数为78．27％外，其余相似度均低于70．0％；ESBLs大肠埃希菌阴性株中除少数几对菌株相似性系数较高外，其余呈散在分布，且电泳带存有6条以上的不同条带，为流行病学无关的不同克隆。结论 大肠埃希菌对常用抗生索耐药性明显增高，且呈多重耐药趋势；该研究尚不能证明存在大肠埃希菌爆发性流行感染，提示可能存在院内感染大肠埃希菌的优势克隆；PFGE基因分型方法是耐药性与流行状况分析的有效手段。

Study of drug resistance of Escherichia coli and its genotyping related

Objective To study the drug resistance of Escherichia coli and its related gehotyping;to study the epidemic and the change of resistance of Escherichia coli to several common antibiotics.Methods Using the conventional verification technique to identify the species;K-B method was used to investigate the drug resistance of Escherichia coli to 19 common antibiotics and identify the existence of ESBLs;genotying was performed by PFGE method.Results Escherichia coli had a higher drug resistance to penicillins,quinolones and aztreonam obviously;imipenem and meropenem got to be the foremost chosen drugs for those patients infected by Escherichia(coli);ESBLs were detected by phenotype and the positive rate was 28.60%;All of the strains were performed by PFGE method resulting in 69 strains including 22 of ESBLs producing Escherichia coli,and 47 non-ESBLs(producing) strains;only four strains were verified as epidemiological related because their dice coefficient index was higher than 85%.The others were verified as non-epidemiological related since their different lanes were more than six.Conclusion Escherichia coli had greatly increased the resistance to many antibiotics;and had a trend of multi-resistance;PFGE genotyping was an effective way for drug resistance and epidemic analysis.