Affiliation:
1. Department of Microbiology, University College Cork, National University of Ireland, Cork, Ireland
Abstract
ABSTRACT
Vibrio cholerae
, the causative agent of cholera, is a natural inhabitant of the aquatic ecosystem. We examined a unique collection of
V. cholerae
clinical and environmental isolates of widespread geographic distribution recovered over a 60-year period to determine their evolutionary genetic relationships based on analysis of two housekeeping genes, malate dehydrogenase (
mdh
) and a chaperonin (
groEL
). In addition, the phylogenetic distribution of 12 regions associated with virulence was determined. Comparative sequence analysis of
mdh
revealed that all
V. cholerae
O1 and O139 serogroup isolates belonged to the same clonal lineage. Single-strand conformational polymorphism (SSCP) analysis of these O1 and O139 strains at
groEL
confirmed the presence of an epidemic clonal complex. Of the 12 virulence regions examined, only three regions,
Vibrio
seventh pandemic island 1 (VSP-I), VSP-II, and RS1, were absent from all classical
V. cholerae
isolates. Most
V. cholerae
El Tor biotype and O139 serogroup isolates examined encoded all 12 virulence regions assayed. Outside of
V. cholerae
O1/O139 serogroup isolates, only one strain, VO7, contained VSP-I. Two
V. cholerae
El Tor isolates, GP155 and 2164-78, lacked both VSP-I and VSP-II, and one El Tor isolate, GP43, lacked VSP-II. Five non-O1/non-O139 serogroup isolates had an
mdh
sequence identical to that of the epidemic O1 and O139 strains. These isolates, similar to classical strains, lack both VSP-I and VSP-II. Four of the 12 virulence regions examined were found to be present in all isolates:
hlyA
,
pilE
, MSHA and RTX. Among non-O1/non-O139 isolates, however, the occurrence of the additional eight regions was considerably lower. The evolutionary relationships and multilocus virulence gene profiles of
V. cholerae
natural isolates indicate that consecutive pandemic strains arose from a common O1 serogroup progenitor through the successive acquisition of new virulence regions.
Publisher
American Society for Microbiology
Reference68 articles.
1. Albert, M. J., A. K. Siddique, M. S. Islam, A. S. Faruque, M. Ansaruzzaman, S. M. Faruque, and R. B. Sack. 1993. Large outbreak of clinical cholera due to Vibrio cholerae non-O1 in Bangladesh. Lancet341:704.
2. Genetic Diversity and Population Structure of
Vibrio cholerae
3. Berche, P., C. Poyart, E. Abachin, H. Lelievre, J. Vandepitte, A. Dodin, and J. M. Fournier. 1994. The novel epidemic strain O139 is closely related to the pandemic strain O1 of Vibrio cholerae. J. Infect. Dis.170:701-704.
4. DNA fingerprinting of Vibrio cholerae strains with a novel insertion sequence element: a tool to identify epidemic strains
5. Molecular Analyses of a Putative CTXφ Precursor and Evidence for Independent Acquisition of Distinct CTXφs by Toxigenic
Vibrio cholerae
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