[Genetic determinants of pathogenicity of opportunistic enterobacteria isolated from children with acute intestinal infections].

AIM: Detection of nucleotide sequences of genes controlling synthesis of pathogenicity factors in clinical strains of opportunistic enterobacteria isolated from children with acute intestinal infections (AII), as well as their association with resistance to antibiotics and the course of the infectious process. MATERIALS AND METHODS: 175 clinical strains obtained from children with AII undergoing treatment in Irkutsk state infectious diseases hospital (2007-2010) were studied. Primers to a number of genes detected in Escherichia coli pathogenicity islands, controlling type S and type 1 adhesion; formation of hemolysins; iron-regulatory protein synthesis; capsule formation were used in the study. PCR products analysis was performed by agar gel electrophoresis. RESULTS: Genetic determinants of pathogenicity were detected in bacteria genera Klebsiella, Citrobacter, Enterobacter, Proteus, Kluyvera, Morganella, Pantoea, Serratia. Fragments of hlyA and hlyB genes (hemolysin production) were detected more frequently; less frequently--sfaA, sfaG, fimA (adhesion), as well as irp-2 gene (synthesis of iron-regulatory protein). The largest set of genetic determinants of pathogenicity was noted in clinical strains of Klebsiella spp. Cultures with DNA fragments specific to genes of E. coli pathogenicity clusters were obtained predominately from children aged up to 3 years, had multiple antibiotic resistance and were isolated significantly more frequently in severe forms of AII when compared with strains in which these determinants were not detected. CONCLUSION: The studies performed showed that clinical strains of opportunistic bacteria isolated from patients with AII have a certain pathogenic potential, as evidenced by the presence of genetic pathogenicity markers in them.

[Isolation of bacteria of the family enterobacteriaceae from plant tissues].

Bacteria of the family Enterobacteriaceae were isolated from the tissues of a number of wild and cultivated plants. All the cultures isolated had a broad spectrum of resistance to antibiotics and were highly adhesive to human erythrocytes. The studies conducted indicate the possibility of concentration of microorganisms pathogenic for humans in plant tissues.

[Indications of pathogenic viruses in water of Lake Baikal and its tributaries]. / Indikatsiia patogennykh virusov v vode ozera Baikal i ego pritokakh.

The waters of 25 large rivers falling into the Baikal Lake, their mouth water areas and open Baikal Lake areas to a depth of 500 m were for the first time in the practice of researches on the Baikal Lake were investigated for markers of hepatitis A virus and rotaviruses. The investigations showed an insignificant contamination of surface waters with pathogenic viruses. The antigens of all studied viruses and high values of bacteria from the Escherichia coli group were recorded in the areas exposed to chronic man-made pollution. Data on the seasonal changes in the distribution of enteroviruses indicated their absence in the annual cycle in the pelagic area of the lake, which suggests that viral particle would not accumulate under the conditions of the Baikal Lake over a long period.