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Kartsev N.N.,State Research Center for Applied Microbiology and Biotechnology | Fursova N.K.,State Research Center for Applied Microbiology and Biotechnology | Pachkunov D.M.,Volga State Technological University | Bannov V.A.,State Research Center for Applied Microbiology and Biotechnology | And 3 more authors.
PLoS ONE | Year: 2015

Enterotoxin-producing Escherichia coli (ETEC) are one of the main causative agents of diarrhea in children especially in developing countries and travel diarrhoea in adults. Pathogenic properties of ETEC associated with their ability to produce a heat-stable (ST) and/or heat-labile (LT) enterotoxins, as well as adhesins providing bacterial adhesion to intestinal epithelial cells. This study presents the molecular characterization of the ETEC isolates collected from the Central and Far-Eastern regions of Russia in 2011-2012. It was shown that all ETEC under study (n=18) had the heat-labile enterotoxin-coding operon elt, and had no the genes of the heat-stable enterotoxin operon est. DNA sequencing revealed two types of nucleotide exchanges in the eltB gene coding subunit B of LT in isolates collected from Cherepovets city (Central region, Russia) and Vladivostok city (Far-East region, Russia). Only one ETEC strain carried genes cfaA, cfaB, cfaC and cfaD coding adhesion factor CFA/I. Expression of LT in four ETEC isolates in the agglutination reaction was detected using a latex test-system. The isolates were assigned to serogroups O142 (n = 6), O6 (n = 4), O25 (n = 5), O26 (n = 2), and O115 (n = 1). Genotyping showed that they belonged to an earlier described sequence-type ST4 (n = 3) as well as to 11 novel sequence-types ST1043, ST1312, ST3697, ST3707, ST3708, ST3709, ST3710, ST3755, ST3756, ST3757 and ST4509. The ETEC isolates displayed different levels of antimicrobial resistance. Eight isolates were resistant to only one drug, three isolates - to two drugs, one isolate - to three drugs, two isolates - to four antibacterials, and only one isolate to each of the five, six and ten antibacterials simultaneously. Genetic determinants of the resistance to beta-lactams and other classes of antibacterials on the ETEC genomes were identified. There are blaTEM (n = 10), blaCTX-M-15 (n = 1), class 1 integron (n = 3) carrying resistance cassettes to aminoglycosides and sulphonamides dfrA17-aadA5 and dfrA12-orfF-aadA2. One isolate ETEC-Ef-6 was found to be amultidrug-resistant (MDR) pathogen that carried both the beta-lactamase gene and class 1 integron. These data suggest the circulation of ETEC in Russia. Further investigations are necessary to study the spread of the revealed ETEC sequence types (STs) and serotypes. Their role in the etiology of diarrhea should be also estimated. © 2015 Kartsev et al. Source

Sidyganov Y.N.,Volga State Technological University | Medyakov A.A.,Volga State Technological University | Kamenskikh A.D.,Volga State Technological University
Chemical and Petroleum Engineering | Year: 2014

The principles of using catalytic devices for emergency and technological utilization of gaseous hydrocarbons that reduce emissions of noxious gases to the atmosphere are discussed. Formulas are deduced to calculate the key design parameters of catalytic devices for utilizing gaseous hydrocarbons and ventilating gas-polluted premises. Introduction of catalytic combustion devices in place of flaring devices will increase the safety of gaseous hydrocarbons utilization. © 2015 Springer Science+Business Media New York. Source

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