Environmental Determination of Indigenous Bifidobacteria of the Human Intestine.

The environmental determination of indigenous (constantly present) bifidobacteria of the human large intestine is considered in this review. Environmental determination (from the Latin determinere, "I determine") is understood as a set of natural phenomena of a habitat (biotope) that determine the role of indigenous microorganisms in the microbiocenosis. Using the symbiotic approach, an attempt is made to identify the environmental conditions for the habitat of bifidobacteria and their physiological effects in the microsymbiocenosis. The features of indigenous bifidobacteria in terms of their nature have been established: evolutionary-genetic (phylogenetic remoteness, genome conservation, metabolic specialization), biochemical (lysozyme resistance, constitutive acetate production), and physiological (microbial "friend-foe" identification, immunoregulation), which are important in adaptation (persistence) and the provision of mutualistic effects and stability of the bifidoflora in the population.

Quantitative method for the determination of antibiotic-resistant gut bacterial strains for the early diagnosis of chronic arthritis.

Based on the clinical and microbiological monitoring of two groups of children aged 3 to 17 years with acute (n=78) and chronic (n=46) course of reactive arthritis (ReA), a method for early diagnosis of chronic arthritis was developed by determining the number of antibiotic-resistant coprostrains in patients with ReA, characterized by the absence of the need to isolate a pure culture of the pathogen and its identification; inoculation of faeces at a dilution of 10-5 on solid 1.5% GRM-agar with an antibacterial agents used in the treatment of a particular patient, at a minimum inhibitory concentration in the resistance range, followed by incubation and counting of the colonies of microorganisms grown on the plate. A significant relationship between the number of antibiotic-resistant gut bacterial strains and the course of arthritis (acute, chronic) was revealed, and the borderline value of the number of antibiotic-resistant gut bacterial strains was determined - 5×103 CFU/g, which allows differentiating the acute course from the chronic one: in the acute course< 5×103 CFU/g, with chronic - ≥ 5×103 CFU/g. The method allows, at the stage of completion of anti-inflammatory therapy in the active phase of the disease, to identify a risk group for the development of a chronic course of arthritis among patients with ReA, which can contribute to timely therapeutic measures aimed at preventing recurrence of the disease and making the patient disabled.

Diagnostic cytokine marker of male infertility - interleukin 4.

Analysis of the study is to assess the diagnostic significance of cytokines in the sperm plasma of men of reproductive age (20 - 45 years) of two groups: of patients with chronic bacterial prostatitis, not complicated by infertility and with loss of fertility. The study of sperm plasma - the WHO standard. Determination of the level of cytokines in seminal plasma - by enzyme immunoassay («Cytokine¼, Russia). Two methods of mathematical statistics were used: discriminant analysis and classification trees (decision trees).The similarity of interpretations of discriminant analysis and decision tree was noted, where the main role in both cases belongs to the cytokine IL-4. The level of sperm IL-4 in combination with therapeutic monitoring can be used for the medical management of patients with chronic prostatitis in order to prevent the development of infertility and to develop methods for screening diagnostics of fertility disorders in men.

[Characterization of the microbiota and cytokine profile of sperm plasma in men with chronic bacterial prostatitis].

BACKGROUND: One of the leading causes of the occurrence of chronic bacterial prostatitis (CBP) in men is infection, microecological disorders of the urogenital tract and cytokine-mediated mechanisms of inflammation of the prostate gland, which actualizes a comprehensive study of the clinical and bacteriological features of CBP from the perspective of a symbiotic approach in the framework of a new scientific field - "infectious symbiology". OBJECTIVE: to study the characteristics of spermogram, microbiota, and the cytokine profile in men with chronic bacterial prostatitis (CBP) and CBP complicated by infertility. MATERIALS AND METHODS: A comprehensive study of patients with CBP and CBP complicated by infertility, in comparison with conditionally healthy individuals, was conducted. Species identification of microorganisms was carried out according to biochemical characteristics and the genetic method (sequencing of strains). The biological properties of the microbiota were evaluated: growth properties, biofilm formation, antipeptide activity against the cytokines IL-10, RAIL-1, TNF-, INF- and IL-17 (8 parameters). Immunological parameters of sperm plasma included 13 parameters: the content of cytokines TNF-, INF-, Rail, interleukins (IL) -1, 2, 4, 6, 8, 10, 17, immunoglobulin (Ig) A, lactoferrin and lysozyme. To evaluate sperm plasma, the following quantities were determined: ejaculate volume, pH, sperm plasma liquefaction, total sperm count, sperm count per 1 ml, motility, number of progressively motile, non-progressive motile and motionless spermatozoa, number of round cells, white blood cells, spermatogenesis cells, erythrocytes, erythrocytes, cells, sperm agglutination and aggregation (16 parameters in total). The results are statistically processed. RESULTS: Data were obtained on changes in biofilm formation, antipeptide activity of microbiota (especially pronounced in corynebacteria), sperm plasma cytokine profile (increased TNF , IL-2, 6, 17), as well as IgA and lactoferrin, which can be used to build a prognostic model of reproductive pathology tract of men and their fertile activity. CONCLUSION: The study of the antipeptide activity of microbiota in combination with the cytokine profile of ejaculate allows us to recommend them as a "biotarget" for diagnostic, preventive and therapeutic measures for chronic prostatitis in men, which contribute to solving the medical and social problem of preventing male infertility and contributes to the development of health-saving technologies with incorporating elements of personalized medicine.

Draft Genome Sequence of Klebsiella pneumoniae Strain ICIS-278_PBV, Isolated from the Feces of a Healthy 59-Year-Old Man from Orenburg, Russia.

This report describes the draft genome sequence of Klebsiella pneumoniae strain ICIS-278_PBV, isolated from the feces of a healthy 59-year-old man from Orenburg, Russia. The size of the genome was 5,584,615 bp (57.2% G+C content). Annotation revealed 5,302 coding sequences, including 5,254 proteins, 23 rRNA genes, and 81 tRNA genes.

[METABOLIC PROFILE OF BIFIDOFLORA UNDER DIFFERENT MICROECOLOGICAL CONDITIONS OF THE COLON BIOTOPE IN HUMAN].

AIM: To study the spectrum and level of short-chained fatty acids (SCFA) in supernatant of bifidobacteria under different microecological conditions ofthe colon biotope in human. MATERIALS AND METHODS: Metabolites of 88 bifidobacteria strains isolated from patients when examined for dysbiosis of the colon were investigated. Definition of concentration of SCFA was performed on acidified supernatant samples by a separation method on chromatograph GC-2010 Plus, Shimadzu (Japan). RESULTS: Monobasic acids were found in metabolites of 50 - 100% study cultures of bifidobacteria where the spectrum and level of carboxylic acids in supernatants varied depen- ding on microecological condition of the origin of the discharge. In severe damages of microsymbiocenosis in metabolites of Bifidobacterium spp., summarized concentrations of SCFA, structural index, levels of aceitic and propionic acids were decreased. Strain-specific differences in a metabolic profile of bifidofloia in a composition of individual consortiums were determined. Data obtained indicate the variation of functional (metabolic) activity of dominant strains in different microecological conditions of the human colon. CONCLUSION: Uniquieness of metabolome of every other strain due to their strain specifity determines their functional activity, but a metabolic profile of bifidoflora can serve as the most important criterion for the selection of effective probi- otic drugs for treatment and prevention of dysbioisis in the colon.

[GUT MICROSYMBIOCENOSIS IN CHILDREN WITH REACTIVE ARTHRITIS].

AIM: To study the state of gut microsymbiocenosis in children with reactive arthritis (RA), with the assessment of biofilm formation (BFF) of microsymbionts and the ability to change cytokine levels (their anticyokine activity) in vitro. MATERIALS AND METHODS: The investigation of gut microsymbiocenosis by means of bacteriological method was conducted in 34 children with RA and 25 relatively healthy 3 - 16 year- old children. Microorganisms were identified with the help of MALDI-TOF mass-spectrometry, anticytokine activity (ACA) of microsymbionts - according to Bukharin O.V et al. (2011), biofilm formation - according to O'Toole G.A., Kolter R. (1998). RESULTS: On the ground of species composition differences of gut microbiota discrimination model was created which allowed to separate the group of children with RA from healthy individuals. Microsymbiocenosis of patients with RA was characterized by increasing number of opportunistic microorganisms (OM) (enterobacteria, clostridia, bacteroides, and Candida), BFF and ACA level. CONCLUSION: The obtained data greatly contribute.to the deciphering of spondylo- arthritis and disclose the role of microbial factor under given pathology. Hypercolonisation of human gut with OM, having pronounced ability to BFF and regulating cytokine level, promotes strengthening of arthritogenic potential and serves as additional marker of arthritis development risk in children.

[INTERMICROBIAL <> DISCRIMINATION IN <> PAIR OF PROBIOTIC STRAINS OF ESCHERICHIA COLI M-17 AND E.COLI LEGM-18].

AIM: To use earlier developed method of intermicrobial <> discrimination in <> pair for the assessment of foreignness of probiotic cultures of Escherichia coli M-17 (with pathogenicity island) and E. coli LEGM-18, (without pathogenicity island). MATERIALS AND METHODS: As dominants reference and clinical strains of bifidobacteria were used in the work, cultures of E.coli M-17 and E. coli LEGM-18 were taken as associants, differing in the presence of genes which code colibactin. Detection of the phenomenon of microbial discrimination was conducted according to the developed algorithm (Bukharin O.V., Perunova N.B., 2011) based on the principle ofmetabolite induction as a result of preliminary coincubation ofdominants (bifidobacteria) with supernatant of associants and the formation of feed back in <> pair. Special growth properties, biofilm formation, and antilysozyme activity served as biological characteristics of investigated coliform bacteria. RESULTS: Testing of E. coli M-17 culture revealed depression of biological properties under investigation and it was estimated as <> possibly due to the presence of pathogenicity island whereas E. coli LEGM- 18 (without this frag- ment) sharply strengthened its biological characteristics and was subjected to assessment as <>. CONCLUSION: Use of intermicrobial <> pair is promising as basic method when selecting probiotic strains and cultures for creation of new sym- biotic compositions and is suitable for quality control of probiotic products.

[REGULATING EFFECT OF ASSOCIATIVE MICROBIOTA ON THE RHYTHMS OF BIOLOGICAL PROPERTIES OF FUNGI AND BACTERIA].

AIM: Study the effect of exometabolites of associative microbiota on circadian dynamics of functional parameters, that reflect pathogenic and persistence properties of fungi and bacteria. MATERIALS AND METHODS: Clinical isolates of Candida albicans, isolated-from intestine of healthy individuals and patients with candidosis, as well as clinical isolates and museum ATCC strains Staphylococcus. aureus 25923, Escherichia coli 35218 and Pseudomonas aeruginosa 27853 were taken for study of proliferative, adhesive, catalase, protease, phospholipase, hemolytic, anti-lysozyme, biofilm-forming activity. The results were treated statistically. RESULTS: C. albicans isolates, isolated from healthy individuals were revealed to be indifferent to the effect of bacterial metabolites. Chrono-infrastructure of biological properties of fungi altered under the effect of microbiota metabolites. Hospital isolates of S. aureus, E. coli and P. aeruginosa displayed a relative stability of physiological properties against the effect of bacterial-fungal metabolites as opposed to museum strains. CONCLUSION: The alterations of chrono-infrastructure of biological rhythms of microorganisms by bacterial-fungal metabolites of associants reflect the intensity of the biological system, that is inevitable during the process of formation of inter-microbial interactions.

[IMMUNE REGULATORY PROPERTIES OF BIFIDOBACTERIA METABOLITES DURING EUBIOSIS AND DYSBIOSIS OF THE HUMAN COLON].

AIM: Evaluate immune regulatory properties of bifidobacteria metabolites during eubiosis and dysbiosis of the human colon. MATERIALS AND METHODS: Anti-cytokine activity of metabolites of bifidobacteria clinical strains and their ability to influence the production of pro- and anti-inflammatory cytokines (IL-10) by peripheral blood mononuclear cells of healthy humans was studied, taking into account microecological state of the human intestine. Determination of final concentration of cytokines in experimental and control samples was carried out by EIA. RESULTS: Sensitive parameters, that are suitable for evaluation of stability of human intestine microsymbiocenosis, were detected. The level of microbial seeding, concentration of TNF-α and anti-lysozyme activity turned out to be informative for bifidobacteria in eubiosis conditions. The ability of bifidoflora metabolites to influence the production of pro-inflammatory cytokines (INF-γ, TNF-α, IL-8) by human mononuclears was a significant parameter during formation of 1 - 3 degree dysbiosis. CONCLUSION: The maintenance of physiological state of intestine homeostasis is determined by immune regulatory properties of bifidobacteria metabolites, that is realized via their interaction with both cytokines (anti-cytokine activity) and production of cytokines by host immune cells (peripheral blood mononuclears).

[ACID-BASE MODULATION OF LYSOZYME ACTIVITY IN MEDIUM FOR CULTIVATION OF ENTEROBACTERIA].

AIM: Determination of modulating effect of acid-base state of medium for cultivation of enterobacteria on activity of C-type lysozyme. MATERIALS AND METHODS: Escherichia coli BL21 (DE3) strain for protein expression, Escherichia coli K12 MG1655 model strain, Escherichia coli No. 242 strain, isolated from intestine biotope; 2 Klebsiella pneumoniae strains, one of those contained plasmid homologue of periplasmatic lysozyme inhibitor gene pliC; 1 typical Salmonella enterica ATCC 14028 strain and a Micrococcus luteus ATCC 15307 strain as a control--served as material for the study. The bacteria were cultivated for 24 hours in 2 ml of liquid medium LB at 37 degrees C, 250 rpm. Determination of antilysozyme activity (ALA) was carried out by a photonepehlometrical method according to O.V. Bukharin et al. (1999) with alterations. RESULTS: All the studied microorganisms, including Micrococcus luteus, at the specified conditions 24 hours after cultivation were established to change the pH of the liquid nutrient medium LB from the initial value of 6.6 ± 0.1 to 8.2 ± 0.2 units. ALA determination in the cultivation medium without buffer correction was accompanied by a decline of lysozyme activity at an order of magnitude. The effect was absent during ALA measurement by a standard technique. CONCLUSION: The local shift of acid-base state of biotope under the conditions of buffer system insufficiency results in a reversible alteration of antimicrobial activity of muramidase, that among other non-specific factors of the environment determines the background of interactions on the level of associative symbiosis. This aspect should be taken into consideration during development of models, that are close to real conditions of microsymbiocenotical interactions.

[AEROMONAS BACTERIA ISOLATED FROM BITHYNIIDAE MOLLUSKS AND THEIR HABITATS: SPECIES COMPOSITION AND BIOLOGICAL PROPERTIES. COMMUNICATION 1].

The purpose of this investigation was to study the species composition and biological properties of Aeromonas bacteria isolated from Bithyniidae mollusks and their habitat (a water reservoir). The Bithyniidae mollusks and water from their habitat were the material to be studied. A total of 176 Aeromonas strains were isolated from the mollusks and water. A. veronii, A. hydrophila, and A. ichthiosmia were most common in the mollusks and A. veronii and A. ichthiosmia were in the water. All the strains isolated had hemolytic activity and no lysozyme or plasma coagulase activity. The magnitude of lecithinase and antilysozymic activities and biofilm formation of the Aeromonas bacteria varied with the isolation source of their strains.

[THE STRUCTURE AND SOME BIOLOGICAL PROPERTIES OF GRAM-NEGATIVE BACTERIA CONSTITUTING THE MICROSYMBIOCENOSIS OF PROSOBRANCHIA MOLLUSKS (BITHYNIIDAE). COMMUNICATION 2].

The goal of this investigation was to study the structure and biological properties (antilysozymic, activity and biofilm formation) of gram-negative bacteria isolated from Bithyniidae mollusks and their habitat (water reservoir waters and soil). A total of 160 gram-negative bacterial strains isolated from the mollusks of the Bithyniidae family and their habitat were the material to be, studied. Psedomonas, Comamonas, and Acinetobacter held the lead in the structure of microbiocenosis of Bithyniidae mollusks, the first intermediate host of Opisthorchis filineus, while Acinetobacter did in the habitat. The antilysozymic activity of the water strains was shown to be an order of magnitude higher than that of the strains isolated from the mollusks.

[THE ROLE OF BIFIDOBACTERIA IN THE FORMATION OF HUMAN IMMUNE HOMEOSTASIS].

In the review the materials on the formation of intestinal immune homeostasis through involvement of bifidobacteria which are the key species of microbiota of human colon biotype are presented. Key function of dominant microorganisms, bifidoflora in particular, in intestinal biotype of a host is carried out by means of maintenance of self microorganisms and pronounced antagonism concerning non-self. Realization of this principle in intermicrobial relations allowed to develop algorithm of microbial self-non-self discrimination in microsymbiocenosis on the basis of detected opposite phenomenon (enhancement/suppression) of the main physiological functions of microsymbionts survival (reproduction and adaptation) in dominant-associant pair. Primary discrimination of foreign,material by bifidobacteria is the initial stage of the following "signaling" in the regulation of host immune homeostasis. Further stages of regulation occur by activation of dendritic cells by bifidobacteria with the sequential influence on differentiation of Th0 towards regulatory lymphocytes. The formation of Treg and regulation of immune homeostasis are carried out by bifidobacteria: due to direct activation of dendritic cells (ligand-receptor interactions) and maintenance of optimal cytokine balance.

[BIOLOGICAL PROPERTIES OF BACTERIA OF THE FAMILY ENTEROBACTERIACEAE AS COMPONENTS OF MICROSYMBIOCENOSIS OF THE FIRST INTERMEDIATE HOSTS OF O.FELINEUS].

The objective of the investigation was to study the biological properties (antilysozyme activity (ALA), biofilm formation (BFF), and virulence factors) of different Enterobacteriaceae species isolated from Bithyniidae mollusks and their habitats. A total of 117 strains isolated from Bithyniidae mollusks of the genera Codiella and Bithynia and those from their habitats were the material to be studied. Thus, comparison of the mean values of ALA in Enterobacteriaceae species suggests that the strains isolated from the mollusks and their aqueous habitat did not virtually differ in this indicator. Also, there were no statistically significant differences in the detection rate of the Enterobacteriaceae strains having a pronounced antilysozyme activity and in that of mollusks circulating in the aqueous habitat when compared with the strains isolated from the mollusks. Comparison of BFF in the aqueous bacterial strains and mollusk microbiota representatives revealed the highest values in the former; just lower value was noted in the latter. Soil Enterobacteriaceae isolates had very low BFF values.

[Application of multiplex-PCR for bifidobacteria and propionibacteria genus identification].

AIM: Creation of a PCR test-system for determination of Actinobacteria class bacteria belonging to 2 genera that are the most widely represented among obligate anaerobic microbiota of human intestine: Bifidobacterium and Propionibacterium. MATERIALS AND METHODS: 8 strains of Bifidobacterium spp. and 6 strains of Propionibacterium genus were identified by morphologic, cultural and biochemical properties. Isolation of matrix DNA of the strains for PCR was carried out by "DNA-Express" kit (SPF "Lytech", Russia). Primers for determination of genus membership for obligate anaerobes were developed based on variability of 16S RNA gene by using "Lasergene 7.1" ("DNASTAR, Inc.", USA) program. PCR screening of the isolated DNA was carried out based on "Syntol" LLC primers and reagents. Amplicon detection was carried out by agarose gel electrophoresis. RESULTS: Multiplexing of 2 different primer pairs in a single probe at.68 degrees C annealing temperature for 30 cycles showed the presence of non-specific amplicons that form in samples with bifidobacteria DNA-matrix. The increase of annealing temperature to 70 degrees C and reduction of the number of PCR cycles to 25 resulted in the exclusion of formation of non-specific amplicons. Because the annealing temperature reached the level of values optimal for Taq-polymerase, a 2-phase PCR algorithm could be implemented. This solution allowed reducing the overall time of reaction to 45 minutes. Further increase of annealing temperature to 72 degrees C and reduction of elongation phase up to 15 seconds at 30 PCR cycles did not result in a visible reduction of reaction effectiveness: CONCLUSION: A rapid system for identification of Bifidobacterium and Pronionibacterium genera using a system of 2-phase multiple PCR was developed. The system is part of a screening system for identification of major genera and species of cultured obligate anaerobic bacteria isolated from human intestine biotopes.

[Periplasmic lysozime inhibitior PliC and its role in antilysozime activity of enterobacteria].

Two families of specific inhibitors of type C lysozyme (Ivy and PliC) secreted from the periplasmic space are known in enterobacteria. Microbial capacity for distant lysozyme inactivation (antilysozyme activity) is most pronounced in the strains and species carrying homologues of the pliCgene. The pliC homologue localized in a -200-kbp megaplasmid of Klebsiella pneumoniae was shown to differ significantly in the amino acid composition of the coded polypeptide. Similar to the Salmonella enterica pliC homologue, it possesses a detachable signal part and contains identical functionally critical amino acids of the active center of the inhibitor. Antilysozyme activity of the pliC-positive K. pneumoniae strains was observed at the level corresponding to the highest values found inpliC-positive S. enterica. High level of the antilysozyme activity in K. pneumoniae strains containing the plasmid pliC homologue was found in all studied strains, unlike S. enterica strains carrying the known chromosomal pliC homologue.

[Morpho-functional changes of Staphylococcus aureus biofilms under the effect of batumin].

AIM: Study the effect of batumin isolated from metabolites of Pseudomonas batumici bacteria on the formation of biofilms by staphylococci under the control of atomic force microscopy. MATERIALS AND METHODS; S. aureus 25923 (ATCC) and S. aureus 104 were used as test cultures. Batumin with the degree of purification of 80% was used in the experiments. Microscopy of the preparations was carried out on atomic force microscope SMM-2000 (Proton-MIET Closed Joint-Stock Company, Russia) in contact mode in air environment. Biofilm formation (BFF) was studied by photometric method (O'Toole G.A., 2000). Dissociation of microbial population was detected during seeding of staphylococci into agarized LB medium. RESULTS: Changes of structural component of biofilm were noted visually under the effect of the preparation--exopolymeric matrix and reduction of quantity of adherent staphylococci in the form of separate islet formations. Similar pattern was detected during determination of staphylococci biofilm formation by photometric method. Redistribution of S. aureus clonal structure with the appearance of dissociants that do not possess the ability to form biofilms and reduction of quantity of clones with high values of BFF also occurred under the effect of batumin. CONCLUSION: The data obtained reveal one of the mechanisms of antimicrobial effect of batumin based on suppression of staphylococci biofilm formation by the preparation.

[Algorithm of identification of atypical variants of Staphylococci, pathogens of chronic pyo-inflammatory processes in humans].

Staphylococcal pathogens of chronic relapsing infections, such as cystic pneumosclerosis and osteomyelitis are characterized by atypical morphology of the colonies (atypical variants of staphylococci) and present a subpopulation in clinically significant staphylococci. Since the loss of some phenotypic characteristics important for the genus Staphylococcus due to mutations, identification of such staphylococcal variants is difficult and sometimes impossible. An algorithm of identification of atypical variants of S.aureus (SSCVs) was developed. The advantages of the molecular methods and in particular the tRNA-PCR analysis, as well as the use of the diagnostic preparation Diastaph for correct identification of Staphylococcus atypical variants were shown.

[Interaction of Bifidobacterium bifidum with members of normal microflora in human intestine microsymbiocenosis].

AIM: Study the influence of exometabolites of B. bifidum on biological properties of bacteria that are the members of normoflora and their ability to interact with associative microsymbionts. MATERIALS AND METHODS: Bacterial strains that are members of the normal microflora of human intestine: B. bifidum, Lactobacillus acidophilus, Enterococcusfaecium and Escherichia coli lactose positive non-hemolytic (lac "+"/hly "-") were used. As opportunistic microorganisms cultures of E. coli lactose negative hemolytic (lac "-"/hly "+"), Klebsiella pneumoniae and Staphylococcus aureus were used. Isolation and identification of microorganisms was performed by generally accepted methods according to guidances. In the first series of experiments influence of B. bifidum metabolites on biological properties of microorganisms that are members ofnormoflora was studied. In the second series--the influence of bifidobacteria supernatants on interrelations of B. bifidum, L. acidophilus and E. coli lac "+"/hly "-" with opportunistic associants. Growth properties (GP), biofilm formation (BFF) and anti-lysozyme activity (ALA) of microorganisms was studied photometrically. Optical density measurement were performed on ELx808 (BioTek, U.S.A.) photometer. The data obtained were treated by nonparametric method using Mann-Whitney criteria. RESULTS: B. bifidum supernatant was established to stimulate in 33.3-66.7% of cases or did not alter growth/reproduction, BFF and ALA of microorganisms that are characteristic for eubiosis of intestine including bacteria of the same species that could have implications for realization by bifidobacteria ofbiotope colonization resistance. Features of interaction ofexometabolites of bifidobacteria with microorganisms that are characteristic for eubiosis of human intestine consisting in enchantment or changes of effects of the influence of normoflora members on BFF of associants were revealed. The maximum enchantment of inhibitory effect of indigenous strains under the influence ofbifidobacteria was noted in associations E. coli lac "+"/hly "-" E. coli lac "-"/hly "+" as well as E. faecium--S. aureus. CONCLUSION: Thus, the data obtained may be used for detection of mechanisms of functioning of normal microsymbiocenosis in human associative symbiosis.