应用MLST方法对宜昌地区肺炎克雷伯菌分型及主要流行株的鉴定

Multilocus sequence typing of Klebsiella pneumoniae in the City of Yichang

目的应用多位点序列分型(multilocus sequence typing,MLST)对肺炎克雷伯菌进行基因分析,以了解其流行病学特征。方法收集2014年10月~12月三峡大学医学院附属医院分离并鉴定的肺炎克雷伯菌30株。用MLST方法进行分类,利用PCR和测序方法检测7个管家基因gapA、infB、mdh、pgi、phoE、rpoB和tonB,用eBURST3.0和MEGA6.06软件对MLST结果进行分析。结果 MLST法将30个肺炎克雷伯菌株分为17个ST,其中ST23 5株,占16.7%;ST412及ST753各3株,各占10.0%;ST60、ST895、ST340、ST392及ST25各2株,各占6.7%;ST1049、ST268、ST722、ST173、ST307、ST86、ST65、ST660及ST395各1株,各占3.3%。经eBURST3.0分析,17个ST分为2个克隆群(ST340、ST895;ST65、ST25)和1个CC23克隆复合体(ST23、ST25、ST60、ST65、ST86、ST268、ST340、ST395、ST412、ST660、ST722及ST895),其中ST173、ST307、ST392、ST753及ST1049为单个型;MEGA6.06软件分析发现30株肺炎克雷菌在系统发育树上形成3个主要分支,即ST23、ST412及ST753。结论宜昌地区肺炎克雷伯菌分布呈现一定多态性,其中ST23为主要流行菌株。

Objective To investigate the molecular epidemiology of Klebsiella pneumoniae in the City of Yiehang. Methods Thirty clinical isolates of K. pneumoniae were collected in Yichang from September to December 2014 and i- dentified. Seven housekeeping genes specific to K. pneumoniae （gapA, infB, mdh, pgi, phoE, rpoB, and tonB） were amplified and sequenced. Multilocus sequence typing （MLST） was used to classify the sequence types （STs） of K. pneu- moniae. Both eBURST3.0 and MEGA6.06 were used to analyze the diversity of and phylogenetic relationship among all of the STs identified in this study. Results In total, 30 strains of K. pneumonia were isolated, cultured, and identi- fied, and 17 STs were classified using MLST. The 17 STs had certain polymorphisms. In specific terms, 5 strains （170~） were ST23, 3 strains （10~~） were ST412, and 3 strains （10~） were ST753. Two strains （7~~） were ST60, 2 strains （7~） were ST895, 2 strains （7%） were ST340, 2 strains （7~） were ST392, and 2 strains （70./oo） were ST25. One strain was ST1049, 1 was ST268, 1 was ST722, 1 was 8T173, 1 was ST30？, 1 was ST86, 1 was ST65, 1 was ST660, and 1 was ST395. Based on eBURST3.0 analysis, the 17 STs were divided into two clonal groups （ST340 and ST895, ST65 and ST25） and clonal comptex CC23 （ST23, ST25, ST60, ST65, ST86, ST268, ST340, ST395, ST412, ST660, ST722, and ST895）. ST173, ST307, ST392, ST753, and ST1049 were singletons. Based on ST analysis, phylogenetic trees were constructed for all of the K. pneumoniae strains using MEGA6.06. Three major branches （ST23, ST412, and ST753） were identified. Conclusion The molecular epidemiology of K. pneumoniae in Yichang is somewhat diverse. ST23 is the predominant ST, and ST753 has been predominant in local hospitals for short periods.