[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. Serotyping was carried out by a commercial kit of O/K sera. PCR-genotyping was carried out by marker genes of 7 pathogenicity "islands" (VPaI-1-7). RESULTS: All the strains isolated from patients in 2012 had KT-positive and urease-negative phenotype, belonged to O3:K6 serogroup and contained marker genes of 7 VPal that allowed to consider them members of a "pandemic" clone as the other clinical strains from this region. However among 2012 strains an increase of number of antibiotic-resistant variants was established compared with 1997 isolates. CONCLUSION: The data obtained give evidence on the risk of spread of a "pandemic" clone of V. parahaemolyticus in the Far-Eastern region of Russia, a dangerous tendency of antibiotic-resistant variant formation and a necessity to monitor morbidity and the environment with mandatory PCR-detection of genes associated with virulence including integrated into pathogenicity "islands".

[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. Virulence was evaluated by a complex method: hemolytic activity was determined in Kanagawa test (KT), urease--in Christensen medium, PRC-testing of tdh and-trh genes. Serotyping was carried out with a commercial O/K-sera kit. PCR-genotyping was carried out by marker genes of 7 pathogenicity islands (VPaI-1-7). RESULTS: Species membership was confirmed for the studied strains. Serologic typing allowed to detect members of 18 serologic groups among the collection strains. All the collection cultures were divided into 4 groups based on KT-Ure-tdh-trh features recombination. A number of genetic variants were detected, strains belonging to a pandemic group and O3:K6 serogroup were determined. CONCLUSION: A collection of V. parahaemolyticus cultures was formed and characterized by a large set of pheno- and genotypic features. A database was developed including information on strain origins, pheno- and genetic features, with genetic variants given, for ease of use of the collection.

[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. To obtain reliable results of diagnostic application of additional methods of differentiation and identification these two species of bacteria are needed. The study was organized to comparatively evaluate effectiveness of biochemical testing, polymerase chain reaction analysis and mass-spectrometry technique in differentiation of species of Vibrio parahaemolyticua and Vibrio alginolyticus. The study implemented analysis of methods of differentiation of species of Vibrio parahaemolyticua and Vibrio alginolyticus using model of collection including atypical strains of these species. To substantiate species belonging of strains of Vibrio parahaemolyticua and Vobrio alginolyticus such techniques are to be additionally applied to biochemical methods of identification as polymerase chain reaction analysis with species-specific primers of genes of metalloproteinase (collagenase) vppC and vapC. The MALDI-TOFF method of mass-spectrometry can be used as additional effective method of identification and inter-species differentiation of species of Vibrio parahaemolyticua and Vibrio alginolyticus isolated from various sources.