Genomic diversity among Vibrio cholerae O139 strains isolated in Bangladesh and India between 1992 and 1998

In order to assess the extent of genomic diversity among Vibrio cholerae O1 39 strains, restriction fragment length polymorphisms in two genetic loci, rrn and ctx, were studied. Analysis of 144 strains isolated from different regions of Bangladesh and India between 1992 and 1998 revealed the presence of at least six distinct ribotypes (B-I through B-VI) of which three were new ribotypes, and one of these was represented by a nontoxigenic O139 stra in. Strains of ribotypes B-I through B-V shared 11 different CTX genotypes (A through K), Antimicrobial resistance patterns of the strains varied inde pendently of their ribotypes and CTX genotypes. Results of this study sugge st that V. cholerae O139 is undergoing rapid genetic changes leading to the origination of new variants, and temporal changes in antimicrobial resista nce patterns may be contributing to the selection of different variants. (C ) 2000 Federation of European Microbiological Societies, Published by Elsev ier Science B.V. All rights reserved.