[Genomic variability of vibrio cholerae El Tor biovariant strains].

The authors performed comparative analysis of the genomes of 145 clinical and environmental isolates of Vibrio cholerae El Tor biovariants using single locus and multiplex PCR. The study found that clinical strains isolated from patients with cholera formed a genetically homogenous group, where bacterial chromosome contained all the tested virulence genes, situated on mobile genetic elements that had been acquired by the pathogen at various stages of its evolution. Strains isolated from water ecosystems during interepidemic period were heterogeneous and formed three groups: a small number of virulent strains; non-toxigenic vibrio strains that, in the process of reductional variation in their new econiche, had only managed to maintain individual virulence genes; non-pathogenic "water" vibrios, whose chromosome contained only the genes from its core part, mobile genetic elements being optionally represented only by the persistence island.

[Differences in virulence genes in Vibrio cholerae eltor strains isolated from different sources in Turkmenistan territory].

Polymerase chain reaction (PCR) detected the presence of various genes associated with virulence in genome of strains V. cholerae eltor isolated in Turkmenistan territory during epidemic and epidemic-free perios. It was found that a complete set of virulence genes (ctxA+, tcpA+ and toxR+) contained strains isolated from patients, carriers and environment only in cholera epidemics.

[Characterization of Vibrio cholerae eltor isolates according to their epidemic potential using new diagnostic cholera bacteriophages eltor ctx+ and ctx- and by the polymerase chain reaction].

The epidemic potential of 113 V. cholerae eltor strains of different origin was determined with new diagnostic cholera bacteriophages eltor ctx+ and ctx-, as well as the test for hemolytic activity. Of these strains 50 were epidemically safe and 51 were epidemically dangerous, while the epidemic potential of 12 other strains could not be detected.