[Rate and level of contamination of potentially dangerous water supply facilities in Moscow region by Legionella pneumophila].

Aim: To assess rate and level of contamination by Legionella pneumophila of cooling water systems in industrial facilities as well as hot water supply systems of administrative buildings in Moscow region.

Materials And Methods: Cooling water systems of 8 industrial facilities and hot water supply systems of 12 administrative buildings or complexes located in Moscow or Moscow region were examined. Samples of water, washes and biofilms were studied by bacteriologic methods and RT-PCR.

[Assessment of bactericidal activity of disinfectants against Legionella on the biofilm model].

Comparative assessment of bactericidal activity of different disinfectants against Legionella biofilms was conducted. Monospecies biofilms of 3 strains of Legionella pneumophila obtained on plastic plates in stable conditions were used as models. It has been shown that for degradation of biofilms as well as for prophylactic action of disinfectants in preventing formation of biofilms on plastic surfaces, higher concentrations of preparations were needed as compared to their bactericidal concentrations for culture of Legionella determined by method of serial dilutions.

[Multiplication of Listeria in milk products].

The results of the evaluation of the multiplication dynamics of Listeria cells in milk and Bifidok, a lactic acid product, are presented. The samples were inoculated on thioglycol agar and studied at different exposure time after incubation at 37 degrees C, 20 degrees C and 4 degrees C. The study revealed the intensive multiplication of Listeria cells in milk, also during storage in a household refrigerator.

[The detection and study of the dynamics of the count of nonculturable forms of Yersinia pseudotuberculosis in the environment by using the polymerase chain reaction].

On the basis of the polymerase chain reaction (PCR) a test system permitting the detection of Y.pseudotuberculosis in different environmental objects was developed. On a model approximating natural conditions the dynamics of the amount of these bacteria in sterile soil extract were studied.

[Potential hosts and routes of the circulation of Yersinia pseudotuberculosis in an aqueous ecosystem].

The interaction between Y. pseudotuberculosis and different representatives of the aqueous and, partially, soil biocenosis was studied. The study revealed that invertebrates of the plankton and benthos (water fleas, cyclops, mollusks, Oligochaeta, larvae of insects), as well as fish and higher plants, ensured the prolonged existence of Yersinia in water.

[Pseudomonads as parasites of protozoa].

The experimental study of the interaction of Tetrahymena pyriformis with different microorganisms of the genus Pseudomonas, isolated from the soil, was made. The study revealed that T. pyriformis phagocytosed some Pseudomonas pigment-forming species (P.

[An experimental study of Yersinia in plants].

Y. enterocolitica and Y. pseudotuberculosis have been experimentally found to penetrate into plants (cabbage, salad, pea, oat) from infected soil and water and to remain in different plant organs (roots, seeds, leaves) up to 30 days (the term of observation).

[Yersinia in plants].

Plants collected on the plots of land formerly irrigated with sewage water from a swine breeding complex (in sewage and the soil Yersinia had been earlier detected) were studied. In 4.9% of plant samples Yersinia were detected (Y.

Analysis of factors which determine the existence of Yersinia pseudotuberculosis in a saprophytic phase.

Data are presented on the effects of a variety of abiotic and biotic environmental factors on the existence and changes in the numbers of Y. pseudotuberculosis. Experiments with sterile soil showed that Y.

[The use of bismuth-sulfite-agar as a solid differential medium for isolating bacteria of the species Y. enterocolitica and Y. frederiksenii].

The potentialities of bismuth-sulfite-agar (BSA) medium as a differentiating medium for the isolation of Y. enterocolitica and the related species have been under study. Y.

[Use of a genetically labelled strain for the analysis of Yersinia pseudotuberculosis population dynamics in natural soils].

The Rifr mutant of Y. pseudotuberculosis, capable of producing pure cultures in media with a high content of rifampicin, has been used for an accurate quantitation of this microorganism in various kinds of natural (nonsterile) soil in controlled laboratory and field experiments. The main biological characteristics of the mutant have been identical to those of the parent strain.

[Enhancement of the phagocytic activity of cells of the mononuclear phagocytosing system by the peroral administration of lactobacilli].

The phagocytic function of the peritoneal exudate cells after oral and intraperitoneal administration of Lactobacillus casei subsp. casei, L. plantarum and L.

[Rapid diagnosis of dysbacteriosis by detecting beta-aspartylglycine in the feces in an experiment].

In experiments on Fischer rats (F-344), both with common microflora and germ-free, the influence of the systemic destination of different antibiotics (tetracycline + ampicillin, gentamicin + kefzol, gentamicin, fradizine) on the intestinal microflora, the content of beta-ospartylglycine in feces and the colonization resistance of the intestinal tract to Staphylococcus aureus B-243 and Pseudomonas aeruginosa No. 93 has been studied. The early appearance of beta-aspartyl-glycine in the supernatant of fecal samples has been shown to be the first sign of dysbacteriosis and to indicate the decrease of the colonization resistance of the intestine to opportunistic bacteria.

[Interrelation of virulent and avirulent (vaccinal) strains of Shigella flexneri 2A in long-term bacterial carriage in gnotobiotic rats].

The ability of S. flexneri 2a virulent and avirulent (vaccine) strains No. 516 and No.

[Adaptation of the antibiotic-resistant bifidobacteria in the intestines of normal and pathogen-free animals].

Antibiotic-resistant bifidobacteria have the ability to actively interact with mucosal tissue from the intestine of mice and rats in vitro and to adapt well in the intestinal tract of normal and germ-free rats, when introduced both with and without antibiotics; in some cases antibiotics enhance the ability of bifidobacteria to adapt in the intestine. The interaction between antibiotic-resistant bifidobacteria and mucosal tissue from the intestine remains unaffected by the prolonged action of 0.1M SDS and Tween-80 solutions, 0.

[Latent bacterial carrier state and resistance to colonization after antibiotic therapy].

The enteral administration of antibiotics has been shown to induce the occult carriership (persistence) of sporulating Gram-positive bacilli inhabiting the intestine before the use of antibiotics and V. eltor introduced orally after the administration of antibiotics is stopped. After the prolonged use of some antibiotics the intestinal tract has been found to become an inadequate environment for the life of nonpathogenic E.

[Immunoglobulins A and G in the intestinal secretions of rats in different microbiologic conditions].

Experiments were made with 3 groups of inbred CDF (F344) Crl rats: 30 germ-free, 30 conventional and 18 germ-free animals infected orally with Shigella flexneri 2aN 516. Secretory IgA (S-IgA) was isolated from gut secretion of the conventional rats to obtain rabbit antiserum against it. The levels of S-IgA, IgA and IgG in blood serum and gut secretion were determined.

[Morphological and immunomorphological changes in the intestines and regional lymph nodes of gnotobiotic rats--chronic carriers of Vibrio cholerae El-Tor].

In the course of chronic carrier state of El-Tor vibrio cholerae gnotobiotic rats develop an immunomorphological reaction in the mucous membranes of the small and large intestines, Peter's patches, and mesenterial lymph nodes consisting in activation of reactive centers of follicles, hyperplasia of reticular cells, and an increase in the number of pyroninophilic plasma cells. The vibrio cholerae caused no pathological changes in enterocytes and other cells but its inoculation was accompanied by a "minor inflammation" in the intestinal wall and mesenterial lymph nodes. Eosinophilic infiltration in the intestinal tract, intensive mast cell reaction with degranulation in the small and large intestines and regional lymph nodes was observed.

[Local Shwartzman phenomenon in germ-free guinea pig].

Eleven germfree and two monoassociated with the Citrobacter guinea pigs, and 25 conventional animals were injected with the heat-inactivated Citrobacter or E. coli for the induction of the local Schwartzman phenomenon. All the gnotobiotic pigs gave a positive reaction.

[Citrobacter persistence in the intestinal tract of guinea pigs depending on the microecological status].

Gnotobiological studies were conducted on germ-free guinea pigs. Association of the animals with the citrobacteria 5396/38 strain led to the reproduction of these bacteria in numbers exceeding the sum total number of all the representatives of the normal microbial flora in the conventional animals. Association lasting for a period of 46 days caused no antibody formation in the blood serum of these animals in difference to conventional guinea pigs immunized parenterally.