Molecular-epidemiological diversity of V.cholerae strains isolated in Siberian and the far eastern regions of the Russian Federation
Abstract number: P1732
Kozhevnikova A., Balakhonov S., Kulikalova E., Urbanovich L., Breneva N., Afanas'ev M.
Objectives: Cholera is a severe gastrointestinal disease that due to Gram-negative bacterium Vibrio cholerae. Threat of infection's carries from Africa and South-Eastern Asia demand to effective molecular-typing based surveillance measures. The purpose of this study was to evaluate molecular-epidemiological diversity of V. cholerae strains isolated in Siberian and the Far Eastern regions of Russia.
Methods:V. cholerae strains (n = 32) have been selected during epidemiological monitoring of Siberia and Far East from 1994 to 2005. Sample set include toxigenic strains (n = 14) from patient and environmental samples, isolated during outbreaks and sporadic cases of cholera in 1994, 1997 and 1999 years and non-toxigenic strains (n = 18) from environment. Strains' isolation and identification was performed according to WHO protocols. Detection of virulence's determinants (ctxAB, tcpA, toxR, attrS, zot, rstC, nanH, ompU), fragments of pandemic islands (VSP-I and VSP-II) and determinants of environmental persistence (hapA1, mshQ and A, mbaA1 and A2, vpsR) was performed by previously described PCR systems. Standard procedure of VNTR typing, that based on amplification of five loci VcA, VcB, VcC, VcD and VcG, was carried out as described previously.
Results: Twenty nine strains (90.6%) belonged to the O1 serotype, all were identify as El-Tor biovar. Three strains belonged to the O 139 serotype. Main virulence's determinants (ctxAB and tcpA) were detected in 14 (14/32; 43.8%) strains and 11 (11/14; 78.6%) of them had fragments of VSP-I and VSP-II. Significant association between presence of environmental persistence's and virulence's determinants did not observe. Nineteen different VNTR profiles were identified, including 13 (68.4%) unique and 19 strains grouped into six clusters (from 2 to 6 strains in each). Seven main VNTR genotypes formed large subgroup that included strains isolated from patients and environmental samples during cholera outbreaks. Among strains belonged to these VNTR-genotypes we observed complete set of virulence's determinants and fragments of pandemic islands.
Conclusion: Seven VNTR-genotypes, which associated with worsening of cholera's situation in Siberia and Far East, were revealed. VNTR typing demonstrates sufficient discrimination power and, in combination with virulence's and pathogen's determinants PCR detection, may be useful for V. cholerae typing in Siberian and Far Eastern regions of Russia.
|Session name:||Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases|
|Location:||Vienna, Austria, 10 - 13 April 2010|
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