Molecular epidemiological study on emerging enteric infections in Asia

亚洲新发肠道感染的分子流行病学研究

基本信息

批准号：
14256004
负责人：
NISHIBUCHI Mitsuaki
金额：
$ 21.38万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

We studied the DNA fingerprints of new pandemic strains of Vibrio parahaemolyticus isolated in Thailand and Vietnam by using the pulsed field gel electrophoresis(PFGE) method. The results indicated that strains harbored in molluscan bivalves are responsible for infection in Thailand and that clear transition of O3:K6 serotype to O1:K25,etc. occurred in Vietnam. The nucleotide sequences of 11 genes in 60 pandemic strains representing the isolates in various Asian countries were combined and analyzed. The result indicated that O3:K6,O4:K68, and O1:KUT strains are phylogenetically related and possible ancestral strains of the pandemic strains were found.Of the 20 ctx^+ Vibrio cholerae strains isolated from the seafoods in Malaysia 15 strains belonged to the new serotype (O139). These strains and ctx^+ V.cholerae strains isolated in India and Bangladesh and from international travelers were subjected to the PFGE-dendrogram analysis. The phylogenetic relationship among these strains suggested that Malaysian O139 strains were introduced from the Bengal area in two separate occasions. The nucleotide sequences of five genes of 79 strains of V.cholerae including the above strains were determined and analyzed by a multilocus sequence typing approach. The result supported the phylogenetic relationship of the strains obtained by the PFGE method.Our study on Escherichia coli O157 suggested this organism is widely distributed in Asian environment. However, considerable number of the environmental strains produced very little amount of Stx2. This was due at least in part to the change in the DNA sequence around the Q gene. This genetic change and the fact that very few patients infected by E.coli O157 are reported in Asian countries appear to be related.

我们利用脉冲场凝胶电泳（PFGE）方法研究了在泰国和越南分离的副溶血性弧菌新流行菌株的DNA指纹。结果表明，软体动物双壳类中携带的菌株是泰国感染的原因，并且O3：K6血清型明显转变为O1：K25等。发生在越南。对代表亚洲各国分离株的 60 个大流行毒株中 11 个基因的核苷酸序列进行了组合和分析。结果表明，O3：K6、O4：K68和O1：KUT菌株在系统发育上相关，并发现了大流行菌株的可能祖先菌株。从马来西亚海鲜中分离出的20 ctx^+霍乱弧菌菌株中，有15株属于新血清型（O139）。对这些菌株以及在印度和孟加拉国以及从国际旅行者中分离出的 ctx^+ 霍乱弧菌菌株进行了 PFGE 树状图分析。这些菌株之间的系统发育关系表明，马来西亚 O139 菌株是在两次不同的情况下从孟加拉地区引入的。采用多位点序列分型方法对包括上述菌株在内的79株霍乱弧菌的5个基因的核苷酸序列进行了测定和分析。结果支持了PFGE方法获得的菌株的系统发育关系。我们对大肠杆菌O157的研究表明该微生物广泛分布于亚洲环境中。然而，相当多的环境菌株产生的 Stx2 量非常少。这至少部分归因于 Q 基因周围 DNA 序列的变化。这种基因变化与亚洲国家极少数感染大肠杆菌 O157 的患者这一事实似乎有关。