[Diagnostic bacteriophage V32 as a tool for the rapid identification of Escherichia coli serogroup O157.]

Bacteriophage V32, a representative of bacterial viruses of the Myoviridae family Ounavirinae subfamily, is proposed for search and identification of E. coli O157 serogroup, including Shiga-toxin producing E. coli O157:H7 (STEC O157:H7), among cultures of enterobacteria from the primary seeding of the material studied. Phage genome containes a linear double-stranded DNA of 87875 base pairs with G/C-content of 38.9% and includes 132 open reading frames (ORF). In the genome, there are no determinants of antibiotic resistance, virulence genes of STEC and other well-known pathogroups of E. coli. It has been established that phage V32 has lytic activity against all studied cultures of E. coli O157 serogroup (n=183) isolated from people and farm animals in various regions of the Russian Federation, as well as in Japan and Italy. At the same time, the phage lyses only 6 of 182 strains (3.3%) of E. coli not belonging to the O157 serogroup and is not active against strains of other enterobacteria. That is, the phage has a high specificity. The use of bacteriophage V32 as a diagnostic tool is a highly efficient, fast, cheap and simple method for identifying E. coli serogroup O157, including the serotype E. coli O157: H7, in any bacteriological laboratory without special equipment and special training of performers.

[Molecular-genetic characterization of shiga-toxin producing Escherichia coli isolated during a food-borne outbreak in St. Petersburg in 2013].

UNLABELLED: Shiga toxin-producing Escherichia coli (STEC) food-borne infections are reported worldwide and represent a serious problem for public healthcare. In the Russian Federation there is little information on epidemiology and etiology of STEC-infections as well as on molecular-genetic peculiarities of STEC pathogens. OBJECTIVE: Our aim was to describe a food-borne outbreak as hemorrhagic colitis (HC) along with hemolytic uremic syndrome (HUS), enterocolitis, and acute gastroenteritis in children in St. Petersburg in 2013. METHODS: Epidemiological, microbiological, molecular-genetic and bioinformatic methods were applied. RESULTS: Objects to study were clinical specimens, milk and food samples, as well as STEC strains isolated during the outbreak. The outbreak of food-borne infection was found to be caused by STEC-contaminated raw milk as confirmed by epidemiological analysis, detection of STEC DNA and isolation of relevant pathogens in milk and sick children fecal specimens. The whole-genome sequencing revealed two groups ofpathogens, E. coli O157:H7 and E. coli O101:H33 among collected strains. Group I strains were attributed to the previously known sequence type ST24, while group II strains belonged to the previously non-described sequence type ST145. In strain genomes of both groups there were identified nucleotide sequences of VT2-like prophage carrying stx2c gene, plasmid enterohemolysin gene, and gene of the STEC main adhesion factor intimin. Gene of intimin gamma was identified in E. coli O157:H7 strains and intimin iota 2 in E. coli O101:H33 strains. The latter previously was identified only in enteropathogenic E. coli (EPEC) strains. CONCLUSION: The additional knowledge of epidemiology and biology of STEC pathogens would assist clinicians and epidemiologists in diagnosing, treating and preventing hemorrhagic colitis.

Bacteriocins reduce Campylobacter colonization and alter gut morphology in turkey poults.

Campylobacter is a leading cause of food-borne illness in the United States. Recent evidence has demonstrated that bacteriocins produced by Bacillus circulans and Paenibacillus polymyxa reduce cecal Campylobacter colonization in broiler chickens infected with Campylobacter jejuni. As Campylobacter coli is the most prevalent Campylobacter isolate recovered in turkeys, the objectives of the present study were to evaluate the efficacy of these bacteriocins against C. coli colonization and their influence on the gastrointestinal architecture of young turkeys. In 3 separate trials, a total of 135 day-of-hatch poults (n = 45/trial) were orally challenged on d 3 with approximately 10(6) cfu of a mixture of 3 C. coli isolates. Immediately before bacteriocin treatment (d 10), cecal Campylobacter concentrations averaged 1.1 x 10(7) cfu/ g of cecal contents (n = 15/trial). On d 10 to 12 posthatch, 2 bacteriocin treatment groups were given free access to feed supplemented with purified, microencapsulated bacteriocins, whereas the positive control treatment group had access to untreated feed (n = 10/treatment group per trial). At the end of the 3-d dosing period, ceca and duodenal loops were collected for analysis. In each of the 3 separate trials, treatment with bacteriocin eliminated detectable ceca Campylobacter concentrations (detection limit, 1 x 10(2) cfu/g of cecal contents) vs. controls (1.0 x 106 cfu of Campylobacter/g of cecal contents). Duodenum crypt depth and goblet cell numbers were also reduced in turkeys treated with either bacteriocin vs. controls (P < 0.05). The dynamic reduction in crypt depth and goblet cell density in turkeys dosed with bacteriocin may provide clues to how bacteriocins inhibit enteric Campylobacter.

[Characterization of Escherichia coli strains O157:H7, isolated on the territories of the Central Federal District].

The characterization of E.coli strains O157:H7, isolated from humans and animals on some territories of the Central Federal District, is presented. Among the isolates from human outbreaks, related and, probably, related cultures prevailed, while among the isolates obtained from different animals mainly unrelated cultures have been detected. A conclusion has been made concerning the existence of several independent zoonotic reservoirs of E. coli O157:H7 infection on this territory. The advantages and drawbacks of the use of pulse electrophoresis in the characterization of E. coli O157:H7 are discussed. Grounds are given for the necessity of the patients examination with hemorrhagic enetrocolitis for the presence of E. coli O157:H7, as well as for the expediency of having a special item for the registration of this E. coli infection in relevant statistical forms.

[Effect of fosfidomycin on development of various infections in mice]. / Deistvie fosmidomitsina na razvitie nekotorykh infektsii u myshei.

Antibiotic fosmidomycin will know as inhibitor of the nonmevalonate pathway of isoprenoid biosynthesis and as possible antimalarial drug, was shown to possess a certain protective effect on mice experimentally infected with tularemia, tiphus or coli-septicemia. Positive effect on mice with chronic form of tuberculosis was not observed when the animals were given 1 mg of fosmidomycin per capita twice a day. Under oxidative conditions an ESR signal of long living nitroxil free radicals were registered in the water solution of fosmidomycin. The radicals are supposed to be involved in the therapeutic effect of the antibiotic.

[Burkholderia mallei and Burkholderia pseudomallei. Study of immuno- and pathogenesis of glanders and melioidosis. Heterologous vaccines]. / Burkholderia mallei i Burkholderia pseudomallei. Study of immuno- i patogeneza sapa i lemioidoza. Geterologichenye vaktsiny.

Parameters of the infectious activity of B.mallei and B.pseudomallei for animals of various species were determined. Pathomorphological characteristics of the process of malleus and melioidosis were studied on golden hamsters, mice, guinea pigs, rats and monkeys. Tularemia, plague and salmonellosis vaccines were shown to have protective effects in experimental malleus and melioidosis. An insignificant cross immune response between the malleus and melioidosis pathogens was observed.

[Sensitivity of Escherichia coli O157:H7, a pathogen of hemorrhagic colitis, to antibacterial drugs]. / Chuvstvitel'nost' Escherichia coli O157:H7, vozbuditelia gemorragicheskogo kolita, k antibakterial'noym preparatam.

Antibioticograms of enterohemorrhagic strains of serogroup O157 Escherichia coli isolated in the Russian Federation and Japan were comparatively studied. Strains with multiple drug resistance were detected. The main biochemical characteristics of the isolates were investigated. Significant differences in susceptibility spectra of the isolates and in their fermentative properties were revealed.

[Designing the latex test system for express identification of legionella in the external medium and clinical materials]. / Razrabotka lateksnoí test-sistemy dlia uskorennoí identifikatsii vozbuditelia legionelleza vo vneshneí srede i v klinicheskom materiale.

A highly sensitive latex test system for identification of Legionella in the external medium and clinical materials have been designed. Protein antigens and polysaccharide components of the outer membrane of the agent were analyzed. Proteins having a molecular mass of 45, 29, and 24 kDa, as well as a polysaccharide component of LPS were found to be common for all L. pneumophila species. Highly affinic immunoglobulins to the antigenic components obtained were covalently linked with latex particles. The test system developed does not give cross-reactions with other microorganisms. The sensitivity of the system is 10(4) COE/ml. Testing water and clinical material samples confirmed that the developed system is more sensitive than the bacteriological method and the direct fluorescence test. In addition, the system is simple to use, cost-effective, it requires little time (no more than 5 min).