杭州地区产KPC酶大肠埃希菌耐药性及流行性分析

Drug resistance and molecular epidemiological analysis of KPC-producing Escherichia coli strains isolated in Hangzhou

目的了解产肺炎克雷伯菌碳青霉烯酶（KPC）大肠埃希菌的流行情况，加强医院感染控制及防止多重耐药菌大范围播散。方法收集2012年7月至2014年1月杭州市中医院、浙江大学医学院附属第一医院、浙江省中医院和浙江省人民医院共25株碳青霉烯类抗生素耐药大肠埃希菌。利用K-B纸片法测试所有菌株对22种常用抗菌药物的敏感性；PCR扩增确认blaKPC基因，改良Hodge试验确认菌株是否产碳青霉烯酶；脉冲场凝胶电泳（PFGE）及多位点序列分型（MLST）技术进行菌株同源性分析。结果25株大肠埃希菌均产KPC酶，编码blaKPC-2基因。这些产KPC酶菌株对抗菌药物的耐药率较高，尤其对几乎所有β-内酰胺类药物耐药。PFGE分型将25株菌株分为3个主要同源克隆群，克隆群A（4株）、克隆群B（5株）和克隆群C（2株），其余14株为散发克隆。MLST分型则分为8个ST型，其中以ST131型为主，共有14株（占56%），另外还包括ST167型3株，ST2003型3株，其余ST型各有1株，这些ST型之间同源性相距较远。PFGE分型和MLST分型结果基本一致。结论目前我国杭州地区产KPC酶大肠埃希菌以ST131型为主，呈多重耐药性，并且在多家医院检出。耐药菌株的流行具有一定的病区集中性，如重症监护室、急诊科，其余多为散发菌株。

Objective To analyze the epidemiological characteristics of Klebsiella pneumoniae earbapenemase （KPC） -producing Escherichia coli （ E. coli） strains isolated in Hangzhou, China. Methods A total of 25 KPC-producing Escherichia coli strains were collected from four hospitals in Hangzhou from July 2012 to January 2014. Antibiotic susceptibility of the isolates to 22 common anthnierobial agents was determined by using Kirby-Bauer （K-B） disk diffusion method. PCR analysis and gent sequencing were used for blaKPC gene screening. The modified Hodge test was performed to detect the production of carbapenemase. Pulsed-field gel electrophoresis （PFGE） and multi-locus sequence typing （MLST） were used for homology analysis. Results All of the 25 clinical isolates were confirmed to be KPC-producing E. coli strains, harboring the blaKPC-2 gene. These KPC-producing isolates showed high drug resistance rates and were resistant to almost all β-lactam antibiotics. PFGE typing classified the 25 isolates into three main homologous clone groups, including clone group A （4 isolates）, clone group B （5 isolates） and clone group C （2 isolates）, and some single clones （14 isolates）. MLST typing classified the isolates into eight ST types, including ST131 （14 isolates）, ST167 （3 isolates）, ST2003 （3 isolates）, ST410 （1 isolate）, ST457 （1 isolate）,ST1463 （1 isolate）, STnewl （1 isolate） and STnew2 （1 isolate）. The typing results of PFGE and MLST were consistent with each other. Conclusion The prevalent KPC-producing E. coli strains in Hangzhou, China were ST131 type, which were resistant to muhiple antibiotics and had been detected in several hospi- tals. The epidemic of KPC-producing E. coli strain often occurred at some special wards, such as Intensive Care Unit （ICU） and emergency ICU.