湖南省2005年-2010年霍乱疫情分离株的毒力基因PCR及PFGE分型分析

Virulence Gene PCR and PFGE Genotyping analysis of Vibrio cholerae strains isolated from cholera epidemics in Hunan province from 2005 to 2010

目的:了解2005年-2010年湖南省霍乱疫情分离到的O139群霍乱弧菌菌株的病原学特征,研究疫情分离株之间的克隆相关性。方法:采用K-B法进行药敏试验;聚合酶链反应(PCR)检测ctxAB毒力基因;脉冲场凝胶电泳对疫情分离代表株进行PFGE分型分析。结果:33株霍乱弧菌对强力霉素、复方新诺明的耐药率较高,分别为39.39%和75.76%,对环丙沙星、诺氟沙星以及丁胺卡那100%敏感;毒力基因的PCR结果显示为所有疫情分离的O139霍乱弧菌均为产毒株,即霍乱肠毒素基因ctxAB阳性;24株分离自2005年和2010年的7起疫情里的O139霍乱弧菌进行PFGE分型及聚类分析后,共分为3个PFGE带型,所有菌株的带型相似率在83%～100%之间。结论:湖南省2005年-2010年霍乱疫情以O139群为主,引起疫情的全部为产毒株,不同年份不同地区之间霍乱疫情的分离菌株之间存在着紧密相关的流行克隆群,对分离菌株进行耐药性监测和进一步的分子分型分析,有助于霍乱的主动监测和传染来源的追踪。

Objective：To understand the pathogenic characteristics of Vibrio cholerae O139 strains isolated from Vibrio cholerae epidemics in Hunan province from 2005 to 2010 ; to study the colone relations among the strains. Methods ： K - B method was employed to test drug sensitivity ; ctxAB virulence gene was tested by PCR, and finally molecular typing was carried out by pulsed field gel electrophoresis （PFGE） for representative strains isolated from Vibrio cholerae epidemics. Results： 33 Vibrio cholerae O139 stains presented a higher drug resistance rate against doxycycline and sulphame - thoxazole of 39.39% and 75.76%, while a sensitivity of 100% to eiprofloxacin, nor- floxacin and amikacin; The virulence gene PCR results showed all the Vibrio cholerae O139 strains were cholera tox- in genes ctxAB - positive; 24 Vibrio cholerae O139 strains isolated from Vibrio cholerae epidemics in 2005 and 2010 showed 3 PFGE banding types, and all the strains were homology of 83% - 100% by cluster analysis. Conclusion： Vibrio cholerae O139 strains isolated from cholera epidemic in Hunan province from 2005 to 2010 were all ctxAB positive. The strains from different years and regions were found the closely related epidemic clone group strains of cholera;Resistance monitoring and further molecular typing analysis of Cholera strains contribute to the efficient sur- veillance of cholera and infectious source tracking.