[THE IDENTIFICATION AND DIFFERENTIATION OF BACTERIOPHAGES OF HUMAN PATHOGENIC VIBRIO].

The issue of identification and differentiation of large group of bacteriophages of human pathogenic vibrio is still unresolved. In research and practical applied purposes it is important to consider characteristics of bacteriophages for establishing similarity and differences between them. The actual study was carried out to analyze specimens of DNA-containing bacteriophages of pathogenic vibrio. The overwhelming majority of them characterized by complicated type of symmetry--phages with double-helical DNA and also phages with mono-helical DNA structure discovered recently in vibrio. For the first time, the general framework of identification and differentiation of bacteriophages of pathogenic vibrio was developed. This achievement increases possibility to establish species assignment of phages and to compare with phages registered in the database. "The collection of bacteriophages and test-strains of human pathogenic vibrio" (No2010620549 of 24.09.210).

[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".

[The bacteriophages Yersinia pseudotuberculosis: the detection in strains of different O-serovars and their identification].

The sample included five indicator pseudotuberculosis strains. The application of these strains permitted to isolate out of 161 strains of Y. pseudotuberculosis 9 bacteriophages identical by their morphologic and serologic characteristics but having individual particularities in their lytic activity. The test on sensitivity to bacteriophages can be used in laboratory diagnostic to differentiate the strains of Yersinia pseudotuberculosis.

[Identification of Vibrio mimicus bacteriophages].

Lysogeny was studied in Vibrio mimicus; the indicator V. cholerae El Tor strain was selected to identify phages. New V. mimicus phages were obtained and identified, which had a morphological similarity and an antigen affinity for morphological group I cholerae phages. Phage differentiation revealed that morphological group I V. mimicus phages showed certain differences manifested as their lytic activity against V. cholerae strain 1322-69 of serovar 37 while this property was absent in cholerae phages.

[Yersinia enterocolitica bacteriophages: detection and identification].

Five indicator strains of Yersinia enterocolitica 01, 03, 05, 012 serovars were selected, which were used to isolate 7 bacteriophages from 227 Y. enterocolitica strains and 2 bacteriophages from wastewater samples. The specificity of the antigenic composition (3 serovars) and the morphology of phage particles (3 morphological groups) were employed to identify bacteriophages; there were differences in the range of lytic activity and resistance to physical and chemical agents. The specific bacteriophage-susceptibility test showed it possible to differentiate Y. enterocolitica strains.

[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. The use of monoreceptor O-sera O2-O83 made it possible to determine vibrios of 32 serogroups with the dominating role in the etiology of acute enteric diseases belonging to serogroups O18, O62, O82, O37. Genes ctx AB were detected in none of the isolates, 5 of them contained gene tcp A. A group of cultures, sensitive to phage ctx+ and belonging mainly to enteropathogenic serogroups, was detected.

[Dynamics of the isolation and biological properties of Vibrio cholerae cultures, serogroups 01 and 0139, isolated from water reservoirs and sewage water on the territory of the city of Rostov-on-Don]. / Dinamika vydeleniia i biologicheskie svoistva kul'tur kholernykh vibrionov 01 i 0139 serogrupp, vydelennykh iz poverkhnostnykh vodoemov i stochnykh vod na territorii g. Rostov-na-Donu.

The dynamics of the isolation of V. cholerae cultures from various water objects on the territory of Rostov-on-Don during the period of 1994-2001 was analyzed and biological properties of 14 such cultures were studied. In the absence of epidemic complications during the above-mentioned period, a growth in the amount of V. cholerae isolates, serogroups 01 and 0139, including toxigenic V. cholerae 01, was registered. The microbiological and epidemiological aspects of the monitoring of surface reservoirs and sewage were considered and the expediency of the profound and systematic study of its results for epidemiological surveillance on cholera was emphasized.

[Indicator strains of cholera vibrions for detection and primary identification of cholera phages]. / Indikatornye shtammy kholernykh vibrionov dlia obnaruzheniia i pervichnoi identifikatsii kholernykh fagov.

A set of test-strains is suggested; it comprises V. eltor P-13169 and V. cholerae 163-0139 designed for the primary identification of unknown previously choleraic bacteriophages.

[Characterization of Vibrio cholerae eltor in the city of Kazan in 2001]. / Kharakteristika kholernykh vibrionov él'tor, vydelennykh v g. Kazan' v 2001 g.

Information on V. cholerae eltor isolated in the focus of cholera in Kazan in 2001 at different periods of the outbreak is presented. The identity of strains isolated from patients, vibriocarriers and environmental objects, including their antibioticograms (sensitivity to cyprofloxacin and resistance to trimethoprim--sulfamethoxazole, streptomycin, furazolidone and nalidixic acid, which may be regarded as markers), is shown. Variable tandem repetitions in the DNA of 30 isolates strains of different origin have been determined. The results of this determination make it possible to classify all these strains as one genotype, which confirms the suggestion on the circulation of one subclone of the infective agent of cholera in the focus. As revealed in this investigation, the isolated strains are labile with respect to diagnostic phage eltor, while ctx+ strains are resistant to phage eltor ctx+.

[Comparative study of the diagnostic value of new cholera eltor bacteriophages ctx+, ctx-, and KhDF-3, 4, and 5]. / Sravnitel'noe izuchenoe diagnosticheskoi tsennosti novykh bakteriofagov kholernykh él'tor ctx+, ctx-, i KhDF-3, 4, 5]

The comparative evaluation of the diagnostic value of new cholera eltor bacteriophages ctx+ and ctx-, as well as monophages X[symbol: see text]-3, 4, 5, demonstrated their high activity and specificity. Using of these bacteriophages epidemic potential of 95% Vibrio cholerae eltor strains ctx+ and 84.5% of V. cholerae eltor stains ctx- was determined. Commercial monophages X[symbol: see text]-3, 4, 5 were inferior to bacteriophages ctx+ and ctx- in their diagnostic value: only 55% of strains having gene ctxAB were found to be epidemically dangerous, i.e. 45% of strains capable of causing the disease were not detected. On the basis of the results obtained in this investigation cholera eltor bacteriophages ctx+ and ctx- were recommended for introduction into practical use, while further production of cholera diagnostic monophages X[symbol: see text]-3, 4, 5 was recommended to be stopped.

[Studies on halophilic vibrios causing a food poisoning outbreak in the city of Vladivostok]. / Galofil'nye vibriony, obuslovivshie vspyshku pishchevoi toksikoinfektsii vo Vladivostoke.

V. parahaemolyticus and V. alginolyticus strains isolated from patients during an outbreak of an acute enteric disease in Vladivostok in 1997 were studied. All strains were found to possess typical taxonomic signs. V. parahaemolyticus isolated from humans had direct heat stable haemolysin exotoxin. The overwhelming majority of these strains belonged to serovar O3K6. Among the cultures under study 7 phage types were determined: phage types 1, 2, 7, 10 in 8 V. parahaemolyticus strains and phage types 2, 4. 5. 7 in 5 V. alginolyticus strains. The diagnostic halophilic phage lyzed vibrios in 30.2% of strains. The cultures under study were found to be highly sensitive to chloramphenicol, cefotaxime, nalidixic acid and cyprofloxacin. The study proved that the outbreak of alimentary toxicoinfection was caused by vibrios of serogroup O3:K6.

[Vibrio cholerae O139 bacteriophages]. / Bakteriofagi Vibrio cholerae O139.

Cholera bacteriophages have been isolated from 27 lysogenic cultures of V. cholerae O139. As shown the pages under study belong to two morphological groups A1 and F1 and serological types II and XII. The use of prophage typing and the sensitivity test to specific phage made it possible to differentiate V. cholerae strains, serogroup O139.

[Cryostabilization of biological properties of plague phages]. / Kriostabilizatsiia biologicheskikh svoistv chumnykh fagov.

Conditions of cryostabilization of Yersinia pestis phages preserving their biological properties at very low temperature are studied.

[The evaluation of the virulent properties of Vibrio cholerae O1 by using in-vitro methods]. / Otsenka virulentnykh svoistv Vibrio cholerae O1 s pomoshch'iu metodov in vitro.

The virulent properties of V. cholerae O1 (more than 1000 strains) were studied. For this purpose the following methods were used: the determination of hemolytic activity, the express method based on the determination of the speed of mannite oxidation, complex analysis and polymerase chain reaction (PCR). The comparative analysis of the results of the in vitro determination of virulence revealed that the most frequently occurring strains among the strains isolated from humans were vct+ strains (80.5%), hemolysis-negative strains (83.9%) which were virulent (faintly virulent) as determined by complex analysis (38.2%), cholerogenic as determined by the express method (60.2%). Among the strains isolated from the environment were vct- strains (87.4%), hemolysis-negative strains (63.2%) which were virulent as determined by complex (13.1%), as well as by the express method (74.3%). The data of the determination of the vct gene did not correlate with the results obtained by complex analysis. The use of complex analysis was expedient only in the detection of strains sensitive to eltor phage in the dilution routine test of V. eltor strains. The methods for the determination of virulence, available for practical laboratories, were Grieg's method for the determination of hemolytic activity and express method. PCR proved to reliable in vitro method for the determination of the vct gene.

[Phagovars of halophilic vibrios]. / Fagovary galofil'nykh vibrionov.

The results of the phage typing of 164 halophilic vibrios revealed the most frequent combinations of lysing monophages, denoted by numbers: 1 (A, B, C, D), 2 (B, C, D), 3 (B, C) and 4 (C). In accordance with the proposed scheme, the phage typing of 398 cultures from different ecosystems was carried out. Phagovar was determined in 77.1% of the cultures. Most frequently occurred phagovars 1 (31.9%), 4 (15.8%), 3 (6%), and 2 (3.7%). Their proportion was 61%. 11 other phage combination causing the lysis of the cultures constituted 16.1%; 22.9% of the cultures could not be types. The use of the proposed scheme of phage typing permitted the determination of the temporal, regional, ecosystemic features of the circulation of halophilic vibrios in different ecosystems and regions, which was important for epidemiological analysis.

[The reasons for the resistance of Vibrio cholerae to diagnostic phages]. / Prichiny ustoichivosti kholernykh vibrionov k diagnosticheskim fagam.

Phage resistance of 225 strains of cholera germs of O1 group obtained from different countries in 1988-1992 has been analyzed. Change of sensitivity to diagnostic phages was mostly connected with the decrease or loss of agglutinability in cholera sera. Phage resistance is rather conditioned by the change of the surface structures of the cell and by further change of phage reception zones. The increase in the number of strains sensitive to diagnostic phages after 6-12 months of storage evidenced for stabilization of cell wall structures and increase of their viability under relatively favourable conditions of storage.

[The characteristics of Vibrio cholerae isolated in Dagestan in 1994]. / Nekotorye osobennosti Vibrio cholerae, vydelennykh v Dagestane v 1994 g.

A high degree of resistance to cholera diagnostic phages and carriership of prophages characteristic of V. cholerae eltor strains vct+ were shown to be the specific features V. cholerae isolated in Daghestan during the period of June-October 1994. Among the strains under study, isolated respectively in 12 and 18 out of 19 regions of Daghestan, a high proportion was found to have resistance to tetracycline (65%) and chloramphenicol (28.6%). Moreover, some strains were found to be resistant to furagin and erythromycin. Out of 242 strains resistant to antibacterial preparations, 163 strains were found to have multiple resistance. Gentamicin, cipropfloxacin and doxicycline were shown to have high in vitro activity with respect to the strains under study.

[A case of the importation onto the territory of Russia of cholera caused by a new serovar]. / Sluchai zavoza na territoriiu Rossii kholery, vyzvannoi novym serovarom.

Materials on the import of rarely occurring Vibrio cholerae, not belonging to group O1 of serovar O139, to the territory of Russia are presented. The clinical picture of a cholera case is described and the biological properties of V. cholerae, serovar O139, are presented. A suggestion has been made concerning the appearance of a new V. cholerae serovar, capable of ousting V. cholerae eltor, the cause of the seventh pandemic.