Regularities of Cholera Spread in the Volga Basin in 1970-1973

Kologorov, A. I.; Кедрова, О. В.; Пахомов, Д. А.; Piskunova, N. V.; Kovtunov, A. I.; Васенин, А. С.; Кабин, В. В.; Илюхин, А. А.; Грачева, И. В.; Раздорский, А. С.; Сафронов, Валентин

doi:10.21055/0370-1069-2010-2(104)-22-27

Cited by 3 publications

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“…Cluster III was represented by 14 isolates referred to 6 different MLVA types (11, 12, 13, 14, 17, and 18). Twelve strains of them were related to the first import of the El Tor cholera to the Volga Region and Central Russia from the Southeast Asian countries in 1970-1974 [23]. When compared, their allelic profiles show that they differed only in the number of repeats in the two most variable loci of chromosome II (VCA0171 and VCA0283), whereas the loci VC0147, VC0436 7, and VC1650 from chromosome I were identical.…”

Section: Molecular Typing Of the Studied V Cholerae Strains By The Mmentioning

confidence: 99%

MLVA typing of clinical Vibrio cholerae strains isolated during different periods of the current cholera pandemic

Smirnova

Кульшань

Krasnov

2015

Mol. Genet. Microbiol. Virol.

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MLVA typing was performed for five variable loci of the 52 Vibrio cholerae El Tor biovar strains iso lated before the onset and in different periods of the seventh cholera pandemic, as well as for eight strains of the classical V. cholerae biovar-the causative agent of the preceding Asiatic cholera pandemics. It has been shown that the studied strains, which differ in their molecular genetic properties and are characterized by 38 MLVA types, form seven clonal clusters. Clusters I and II were formed, respectively, by V. cholerae strains of the classical biovar and prepandemic V. cholerae strains, whereas clusters III-VII were formed by V. cholerae El Tor biovar strains isolated in different periods of the latest pandemic. It has been shown that the MLVA typing allows us to clearly differentiate V. cholerae El Tor biovar strains into typical and genetically altered strains. The genetically altered strains are characterized by higher virulence compared with the typical strains, as well as the presence of the ctxB gene of the classical cholera vibrio in the genome. The study showed the possibility of differentiating genovariants isolated in different periods and having different structures of pandemicity island VSP II. Since the VSP II structure directly correlates with the epidemic potential of the strains, the possibility of differentiating isolates with intact and deleted VSP II using the MLVA method deserves further research. Based on the obtained results, we can propose a polyclonal origin of different strains of genovariants.

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Section: Molecular Typing Of the Studied V Cholerae Strains By The Mmentioning

confidence: 99%

MLVA typing of clinical Vibrio cholerae strains isolated during different periods of the current cholera pandemic

Smirnova

Кульшань

Krasnov

2015

Mol. Genet. Microbiol. Virol.

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Genomic Diversity of Toxigenic Vibrio Cholerae O1 Biovar El Tor Strains Isolated During Three Waves of the 7th Cholera Pandemic

Smirnova,

Rybal’chenko,

Lozovskiy

et al. 2024

Russian Journal of Infection and Immunity

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Introduction. High genome variability of the 7th cholera pandemic agent, V. cholerae El Tor, led to emergence of genovariants with distinct set of altered genes. The aim of the work was to analyze the dynamics of changes in pathogenicity, epidemicity as well as drug resistance and phylogeny in toxigenic strains of V. cholerae El Tor isolated in Russia and endemic regions during three waves of ongoing pandemic. Materials and methods. We used whole-genome nucleotide sequences of 155 strains, obtained by us (42) and taken from the NCBI Genbank (113). DNA sequencing was performed on Ion PGM platform. Phylogenetic relations were determined based on the Bayesian analysis of core SNPs obtained using Snippy 4.6 software package. Antibiotic resistance was assessed applying disk diffusion test. Results. SNP data revealed that the studied strains (1970-2023) might be divided into three clusters. A clear correlation between each-cluster strain genotype and relevant isolation timing was observed. Separation of genetically altered cluster II and III strains isolated during the 2nd and 3rd waves of the pandemic from typical cluster I strains is associated with acquisition of new DNA regions and mutations in pathogenicity and drug resistance genes. Due to different combination of mutations, cluster III strains are genetically heterogeneous. Genome comparison showed that this diversity increased dramatically during the 3rd wave, which led to emergence of new genovariants with higher pathogenic and epidemic potential. It is demonstrated that antibiotic resistance in strains both from endemic regions and Russia over the past 30 years (1993-2023) has undergone significant changes. Thereat, the changing drug resistance clearly correlated with the occurrence of mutations in various pathogenicity genes. Conclusion. It is shown that over the past two decades the agent genome underwent a rather rapid change resulting in emergence of various genovariants. A change in the pathogen variants in Russia has been established. Strains combining genetic markers of hyper-virulence and multiple drug resistance are of particular concern. Genome variability of the strains identified in points at a need for constant genomic surveillance to obtain data on altering epidemically important properties for timely generation of new diagnostic and preventive means.

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Molecular MLVA Typing of Typical and Genetically Altered Natural Strains of <I>Vibrio cholerae</I> El Tor Biovar

Кульшань

Краснов

Лозовский

et al. 2012

Problemy Osobo Opasnykh Infektsii

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Displayed is the possibility of differentiation between typical and genetically altered strains of Vibrio cholerae biovar El Tor, which vary in their virulence and epidemic potential, by means of MLVA. Determined is a significant genetic diversity of the gene-variants, probably, due to their polyclonal origin and continuous alterations within genome under the influence of varying environmental factors.

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Regularities of Cholera Spread in the Volga Basin in 1970-1973

Cited by 3 publications

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MLVA typing of clinical Vibrio cholerae strains isolated during different periods of the current cholera pandemic

MLVA typing of clinical Vibrio cholerae strains isolated during different periods of the current cholera pandemic

Genomic Diversity of Toxigenic Vibrio Cholerae O1 Biovar El Tor Strains Isolated During Three Waves of the 7th Cholera Pandemic

Molecular MLVA Typing of Typical and Genetically Altered Natural Strains of <I>Vibrio cholerae</I> El Tor Biovar

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