This Article Full Text (PDF) Other Versions of this Article: JB.01959-06v1 189/13/4837    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Pang, B. Articles by Kan, B. Search for Related Content PubMed PubMed Citation Articles by Pang, B. Articles by Kan, B.

 Previous Article  |  Next Article 

J. Bacteriol. doi:10.1128/JB.01959-06
Copyright (c) 2007, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.

Genetic Diversity of Toxigenic and Nontoxigenic Vibrio cholerae Serogroups O1 and O139 Revealed by Array-based Comparative Genomic Hybridization

State Key Laboratory for Infectious Disease Prevention and Control. National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention .P.O. Box 5. Changping, Beijing 102206. P.R. China; National Engineering Research Center for Beijing Biochip Technology, 18 Life Science Parkway, Beijing 102206, P.R. China

^* To whom correspondence should be addressed. Email: kanbiao{at}icdc.cn.

	Abstract

Toxigenic serogroups O1 and O139 of Vibrio cholerae may cause cholera epidemics or pandemics. Nontoxigenic strains within these serogroups also exist in the environment and also some may cause sporadic cases of disease. Herein, we investigate the genomic diversity among toxigenic and nontoxigenic O1 and O139 strains by comparative genomic microarray hybridization, employing the genome of El Tor strain N16961 as a base. Conservation of the toxigenic O1 El Tor and O139 strains is found as previously reported, whereas accumulation of genome changes was documented in toxigenic El Tor strains isolated within the forty years of the seventh pandemic. High phylogenetic diversity in nontoxigenic O1 and O139 strains is observed and most of genes absent in nontoxigenic strains are clustered together in the N16961 genome. By comparing these toxigenic and nontoxigenic strains, we observed that the small chromosome of V. cholerae is quite conservative and stable, outside of the the super-integron region. In contrast to the general stability of the genome, the super-integron demonstrates pronounced divergence among toxigenic and nontoxigenic strains. Additionally, sequence variation in virulence-related genes is found in nontoxigenic El Tor strains, and we speculate that these intermediate strains may have pathogenic potential should they acquire CTX prophage alleles and other gene clusters. This genome-wide comparison of toxigenic and nontoxigenic V. cholerae strains may promote understanding of clonal differentiation of V. cholerae, and contribute to an understanding of the origins and clonal selection of epidemic strains.