Distribution of Vibrio cholerae O1 antigen biosynthesis genes among O139 and other non-O1 serogroups of Vibrio cholerae

The organization and distribution of the genes responsible for O antigen bi osynthesis in various serogroups of Vibrio cholerae were investigated using several DNA probes derived from various regions of the genes responsible f or O1 antigen biosynthesis, Based on the reactivity pattern of the probes a gainst the various serogroups, the cluster of genes responsible for the O1 antigen biosynthesis could be broadly divided into six groups, designated a s class 1-6. The class 3 cluster of genes corresponding to gmd to wbeO, wbe T and a part of wbeU was specific for only the O1 serogroup. The other clus ter of genes (class 1, 2, 4-6) reacted with other serogroups of V. cholerae . These data indicate that serotype conversion in V. cholerae does not depe nd on a simple mutational event but may involve horizontal gene transfer no t only between V. cholerae strains but also between V. cholerae and species other than V. cholerae. (C) 1999 Federation of European Microbiological So cieties. Published by Elsevier Science B.V. All rights reserved.