The seventh pandemic of cholera in Europe revisited by microbial genomics.

In 1970, the seventh pandemic of cholera (7 P) reached both Africa and Europe. Between 1970 and 2011, several European countries reported cholera outbreaks of a few to more than 2,000 cases. We report here a whole-genome analysis of 1,324 7 P V.

Ultrastructural Changes in the Intestine of Suckling Rabbits Infected with Cholerogenic and Non-Cholerogenic nonO1/nonO139 Vibrio cholerae Strains.

We performed an electron microscopic study of the small intestine of suckling rabbits infected with cholerogenic and non-cholerogenic strains nonO1/nonO139 Vibrio cholerae. Cholerogenic strain induced mostly hydropic degeneration of the epithelium typical of cholera toxin effect, while non-cholerogenic strain induced the formation of lacunae along the borders of adjacent epithelial cells typical of hemagglutinin/protease effect. In both cases, reduction of microvilli, destruction of intracellular organelles, two types of mitochondrial reaction (condensation and swelling with destruction of cristae), appearance of myelin figures, defects in the capillary walls, and activation of pinocytosis were observed.

[The differentiation of specimiens of Vibrio parahaemolyticua and Vobrio alginolyticus].

Vibrio parahaemolyticua and Vobrio alginolyticus are phylogenetically closely-related species. They have common ecological niches, same cultural features and similar biochemical characteristics. The phenotype variability and taxonomy similarity of strains of these species impedes differentiation of Vibrio parahaemolyticua and Vobrio alginolyticus according biochemical characteristics.

[Collection of Vibrio parahaemolyticus species members: phenotypic and genotypic characteristics].

Aim: Formation of Vibrio parahaemolyticus collection according to modern methodical opportunities and understanding of causative agent biology.

Materials And Methods: Traditional biochemical tests and PCR-testing of species-specific genes were used to confirm species membership. Catalase, DNAse, proteolytic and tweenase activity was determined by common methods.

[O3:K6 serogroup vibrio parahaemolyticus - the causative agent of food toxic infection outbreaks in Primorsky region of Russian federation].

Aim: Comparative evaluation of biological properties of parahemolytic vibrios that had determined outbreaks and sporadic cases of food toxic infection in Primorsky Region in 2012 and previous years. Materials AND METHODS: 40 clinical strains of Vibrio parahaemolyticus isolated in 2012 were studied in comparison with 62 strains from this region that had been characterized by us previously. Virulence was evaluated by a complex method: hemolytic activitywas determined in Kanagawa test (KT), urease - in Kristensen medium.

[VNTR-genotyping of Vibrio cholerae strains isolated from objects in the territory of Russian Federation in 2012].

Aim: VNTR-typing of Vibrio cholerae strains isolated in the territory of Russian Federation in 2012.

Materials And Methods: 71 Vibrio cholerae O3 and 3 V cholerae O1/O139 strains were used in the study. Genotyping was performed by using PCR for 5 VNTR-loci.

[The development of complex technique of evaluation of virulence of parahemolytic vibrio].

The article deals with results of studying parahemolytic vibrio separatedfrom different sources according their phenotype and genotype attributes associated with virulence. In certain cases the mismatch of results of Kanagava tests and polymerase chain reaction test of gene tdh was established. The need in virulence complex evaluation is substantiated.

[Effectiveness of expression of tdh gene of Vibrio parahaemolyticus depends on two point mutations in promoter region].

A molecular-biological study of the clinical strains of Vibrio parahaemolyticus that contain genes of thermostable direct hemolysin Tdh) and Tdh-related hemolysin (Trh). Using Southern blot hybridization, it is shown that genomes of strains that carry determinants of both hemolysins (tdh(+)-trh+) represent a single copy, whereas in tdh2+RH+ strains, there are two copies (tdh1 and tdh2). All of the examined tdh+trh+ and some of the tdh+trh strains either did not express the tdh gene or did not express the tdh gene (Kanagawa negative or KP-) or expressed it weakly and not often (Kanagawa intermediate, KP+), unlike several Kanagawa positive tdh+trh- strains.

[Study of possibility of formation of Vibrio parahaemolyticus pandemic clones based on retrospective PCR-screening of clinical strains].

Aim: PCR-genotyping of Vibrio parahaemolyticus strains that had caused sporadic diseases in Novorossiysk from 1973 to 1976.

Materials And Methods: 24 clinical strains of V. parahaemolyticus isolated in Novorossiysk, most of which belonged to serogroups O4:K12 and O4:K8; 10 O3:K6 strains--causative agents of gastroenteritis outbreak in Vladivostok (1997) and 3 from Japan (1971) were used.

[Characteristics of Vibrio cholerae Cef (CHO cell elongating factor): bioinformatics analysis and experimental data].

Bioinformatics analysis of the primary and secondary structure of the Vibrio cholerae Cef (CHO cell elongating factor) protein was conducted. Similarity with triacylglycerol lipases and cytotonic toxins of other bacterial species was observed. Cef was predicted to be a heat-tolerant serine lipase with the Kunitz domain and leucine zipper.

Ultrastructural changes in cultured cells under the effect of Vibrio Cholerae hemagglutinin/protease.

Electron microscopic study of changes in cultured cells caused by Vibrio cholerae recombinant hemagglutinin/protease (HA/P) showed significant structural changes, most pronounced in HeLa and L-929 cells not forming a compact monolayer with tight junctions between the cells: formation of numerous vesicles on the cell surface and clasmatosis, vacuolation of the cytoplasm, swelling of mitochondria, clarification of their matrix and crist distortions, and increase in the number of lysosomes. Cytoplasm vacuolation predominated in MDCK culture, while clasmatosis was less intense. Addition of HA/P to CaCo2 cells forming a differentiated polarized monolayer, led to extension of cell-cell spaces not impairing tight junctions, swelling of mitochondria, cytoplasm vacuolation, and clasmatosis on the apical surface.

[Point mutation of the Virbrio cholerae O139 cef (CHO cell elongating factor) gene alters the substrate specificity of its product].

Sequencing of the cef (CHO cell elongating factor) of Vibrio cholerae serogroup O139 revealed one nucleotide substitution (C for T in position 2015) in comparison with classical V. cholerae O1 and two substitutions (AC for GT in positions 2014-2015) in comparison with V. cholerae O1 E1 Tor.

[Characteristics of Vibrio cholerae nonO1/nonO139 serogroup strains that caused diseases in population of Rostov region].

Aim: Genotype characteristic and determination of serological properties of Vibrio cholerae nonO1/nonO139 strains that caused diseases in population of Rostov region from 2000 to 2009.

Materials And Methods: 15 clinical strains of V. cholerae nonO1/nonO139 were studied.

[Study of expression of contact-dependent secretion systems in Vibrio cholerae on the model of Dictyostelium discoideum].

Aim: To detect T3SS and T6SS genes in Vibrio cholerae genomes and assessment of resistance of strains with different genotype characteristics to ingestion by Dictyostelium discoideum amoeba.

Materials And Methods: One hundred thirty-five toxigenic and non-toxigenic strains of Echolerae O1, O139, and non-O1/non-O139 were studied by PCR and on Dictyostelium discoideum model.

Results: T3SS cluster of genes was detected in several non-toxigenic representatives of 01 and non-O1/non-O139 serogroups.

[Serotyping and genotypic characteristic of Vibrio cholerae non-O1/non-O139 serogroups isolated from water of surface basins and sewages of Rostov-on-Don city in 2003 - 2008].

Aim: Determination of serogroup and PCR-genotyping of Vibrio cholerae non-O1/non-O139 strains isolated from surface basins and sewages of Rostov-on-Don city in 2003 - 2008.

Materials And Methods: Seven hundred strains of V. cholerae non-O1/non-O139 serogroups were studied in reaction of slide-agglutination with array of 80 diagnostic sera for non-O1/non-O139 serogroups.

Ultrastructural changes in the small intestine of suckling mice, caused by vibrio cholerae hemagglutinin/protease.

Suckling mice aged 4-5 days were injected with Vibrio cholerae hemagglutinin/protease and ultrastructural changes in their small intestine were studied after 5 h. The preparation caused a statistically significant accumulation of fluid in the intestine, appearance of large gaps along cell-cell spaces in the villi and crypts, intense production and secretion of the mucus by goblet cells. The formation of interepithelial cavities was paralleled by vascular changes, supplemented by extravasal disorders caused by mast cell reaction.

[Virulence of pre-CTXphi-carrying Vibrio cholerae: genotypic and phenotypic characteristics].

Aim: Complex assessment of virulence of cholera vibrios carrying the truncated CTX element (pre-CTXphi prophage).

Materials And Methods: Twenty-two strainsof Vibriocholerae O1 and non-O1/non-O139 were studied by PCR and laboratory models.

Results: Genomes of all strains, besides pre-CTXphi genes, contained genes hapA (hemagglutinin/proteases), cef (CHO cell elongating factor), rtxA (high-molecular cytotoxin), and rtxC (its activator).

[Cholera caused by Vibrio cholerae O1 ctxAB- tcpA+].

Results of analysis of cholera outbreak during which V. cholerae O1 biovar El-Tor ctxAB- tcpA+ was isolated from 2 patients and 30 carriers are presented. Epidemic was caused by contamination of water source and water route of transmission.

[Characterization of enteropathogenic Vibrio cholerae non O1/O139 isolated in Uzbekistan].

The results of the serotyping of 244 V. cholerae non O1/O139 cultures isolated from patients in Uzbekistan in 2000 and 2001 are presented. All isolates were studied by the method of molecular probing and in the polymerase chain reaction for the presence of virulence genes and for sensitivity to phages ctx+, ctx- and hemolytic activity.

[Cloning and expression of Vibrio cholerae zonula occludens toxin (zot) gene in Escherichia coli].

Two recombinant plasmids containing the cloned PCR-amplifled Vibrio cholerae zonula occludens toxin (zot) gene was constructed in orientation providing its transcription from lac-promoter. One of them contained also its own zot promoter. The third plasmid was obtained by subcloning a Vibrio cholerae DNA fragment including intact zot and ace (accessory cholera enterotoxin) genes.

[Toxins of Vibrio cholerae].

Surveyed in the paper are published data on properties, biological activity, genetic determinants and action mechanisms of recently known toxins produced by different strains of Vibrio cholerae irrespectively of their capacity for the synthesis of choleric toxin--the main virulence factor. Their possible importance both for the general clinical pattern of cholera provoked by cholerogenic agents and as independent virulence factors causing diarrhea without cholera is elucidated. The sets and levels of expression of additional toxins can differ for different pathogenic clones and they can correspondingly condition degrees of their epidemic and etiological safety.

Ultrastructural evidence of invasive activity of Vibrio cholerae.

The development of experimental cholera in suckling rabbits is associated with typical cholerogenic syndrome: the presence of Vibrio cholerae in the blood, bile (in 60 and 70% cases, respectively), small and large intestine (in 100% cases). Simultaneously with enterocyte desquamation and increased permeability of the blood-enterocyte barrier, the vibrios are released into villous stroma and then into the microcirculatory bed. the zot toxin is involved in the mechanism of Vibrio cholerae invasion, the corresponding gene is present in the genome of the studied strain.

[The genome polymorphism of Vibrio cholerae ctxAB(-) strains, containing the proximal part of the CTX element].

The comparative analysis of the hybridization patterns of DNA restricts for 20 V. cholerae, groups 01 and non-01 (non-0139), containing the incomplete CTX element (ctxAB-) was carried out with the use of probes, complementary to the genes of the proximal part of the virulence cassettle and flanking its RS1 sequences. This group was found to be heterogeneous both in the number of copies of "truncated" CTX prophage and their localizations in the genome, as well as in the position of the sites of restriction endonucleases HindlII and BglII.

[Effect of various amino acids and ammonium salts in a synthetic culture media on the cholera enterotoxin production].

The influence of amino acids and ammonium salts on the production of cholera enterotoxin (CT) by 3 Vibrio cholerae strains of different biovars and serogroups was evaluated. As revealed in this study, toxin formation in each of the strains was quantitatively and qualitatively determined by their individual sets of amino acids. The amino acid compositions ensuring the maximum production of CT by the V.