[Dynamics of variability of microbiotes of the cavity of the mouth and the great intestinent of young men when changing the conditions of life.]

The purpose of the work is to determine the spectrum, quantity and frequency of occurrence of microorganisms in the oral fluid and large intestine in healthy young men under changes of living conditions. A survey was conducted of 14 nonresident young men, students of the 1st and 2nd courses, studying at Tver State Medical University, which included questions about the place of birth, living conditions, the presence of chronic diseases and the frequency of their exacerbations over the past year, water and food regimes, physical exertion, the presence of bad habits and emotional stress, etc. The oral fluid and feces were examined to determine the spectrum and amount of microbiota of the upper and lower parts of the gastrointestinal tract. As the result of the survey, it was found that the living conditions of all young men significantly worsened among second-year students than freshmen. It was revealed that colon microbiota in sophomores characterized by less diverse than those of first-year, despite of a marked increase in the number of opportunistic pathogens (Stаphylocоccus spp., Strерtocoсcus spp., Clоstridium spp., Васillus spp., Кlebsiеlla spp.) over resident microbes. It was found the decrease in the number and frequency of occurrence of all microbial representatives in the oral microbiota of 2nd year students in comparison with first-year. It was proved that the deterioration of living conditions of nonresident students led to the increase in the number of second-year students with dysbiotic changes in the intestinal microbiota from 86% to 100%, mainly due to the increase in the number of persons with dysbiosis of II and III degree.

Interactive effects of protein and carbohydrates on production of microbial metabolites in the large intestine of growing pigs.

The study aimed at determining the effect of protein type and indigestible carbohydrates on the concentration of microbial metabolites in the large intestine of pigs. The experiment involved 36 pigs (15 kg initial body weight) divided into six groups, fed cereal-based diets with highly digestible casein (CAS) or potato protein concentrate (PPC) of lower ileal digestibility. Each diet was supplemented with cellulose, raw potato starch or pectin. After 2 weeks of feeding, pigs were sacrificed and samples of caecal and ascending, transverse and descending colon digesta were collected for analyses of microbial metabolites. PPC increased the concentration of ammonia, p-cresol, indole, n-butyrate, isovalerate and most of the amines in comparison with CAS. Pectin reduced the production of p-cresol, indole, phenylethylamine and isovalerate in the large intestine compared with potato starch. Starch and pectin increased mainly the concentration of n-butyrate and n-valerate in the colon compared to cellulose. Interaction affected mainly amines. Feeding PPC diet with potato starch considerably increased putrescine, cadaverine, tyramine and total amines concentrations compared with PPC diets with pectin and cellulose, whereas feeding CAS diet with starch reduced their concentrations. There was also a significant effect of interaction between diet and intestinal segment on microbial metabolites. In conclusion, PPC intensifies proteolysis in the large intestine and also n-butyrate production. Raw starch and pectin similarly increase n-butyrate concentration but pectin inhibits proteolysis more efficiently than starch. The interactive effects of both factors indicate that pectin and cellulose may beneficially affect fermentative processes in case of greater protein flow to the large intestine.

Repeated measurements of in vitro fermentation of fibre-rich substrates using large intestinal microbiota of sows.

BACKGROUND: Fibrous ingredients for pig diets can be characterized by in vitro fermentation. In vitro fermentation methods often use a one-time measurement of gas production during the incubation of test substrates with one faecal inoculum. The representativeness of this approach can be questioned as measuring time and number of animals from which inoculum originates may influence fermentation results. An in vitro fermentation trial was conducted incubating three fibrous substrates with three inocula in five replicates (different fermentation runs) to test the influence of run and origin of inocula. RESULTS: Total gas production and maximal rate of gas production differed (P < 0.05) between fermentation runs, but less than substrates (P < 0.01). The ranking order between substrates remained similar for each run. Fermentation of cellulose led to higher coefficients of variation between inocula compared to the fast fermentable substrates oligofructose and soy pectin. Differences ranged from 2% for total gas production up to 25% for maximal rate of gas production. CONCLUSION: One fermentation run can provide representative results for substrate ranking. Using multiple inocula mixed from four faecal samples each leads to high coefficients of variation for slow fermentable substrates like cellulose. Future studies should examine the optimal number of animals for inocula preparation to decrease variation.

Methanogenic archaea in health and disease: a novel paradigm of microbial pathogenesis.

Microbes that produce methane gas, methanogens, were identified as Archaea in the 1970s but their possible role in disease is only emerging now, after they were found in the large intestine, mouth, and vagina. Significant associations were observed, for instance, between levels of methanogens in periodontal pockets and severity of periodontitis, and between quantities of methanogens in the large intestine and diseases such as colon cancer and diverticulosis. Recently, a role for intestinal methanogens in obesity was proposed. The lesson learned is that for methanogens we have to look at their pathogenicity from a different angle in comparison to classic pathogens that invade tissues and release toxins. This type of pathogenicity has not yet been described for methanogens. Instead, methanogens seem to participate in pathogenicity indirectly, favoring the growth of other microbes, which are directly involved in pathogenesis. This indirect role should not be minimized. On the contrary, it has become clear that a fundamental change of approach to the understanding and control of microbial diseases must be implemented. A comprehensive strategy is needed to elucidate the syntrophic associations that are essential for a healthy relation among microbes (including methanogens) and between them and the host organism, and to unveil those associations that lead to disease.

Extensive transmission of microbes along the gastrointestinal tract.

The gastrointestinal tract is abundantly colonized by microbes, yet the translocation of oral species to the intestine is considered a rare aberrant event, and a hallmark of disease. By studying salivary and fecal microbial strain populations of 310 species in 470 individuals from five countries, we found that transmission to, and subsequent colonization of, the large intestine by oral microbes is common and extensive among healthy individuals. We found evidence for a vast majority of oral species to be transferable, with increased levels of transmission in colorectal cancer and rheumatoid arthritis patients and, more generally, for species described as opportunistic pathogens. This establishes the oral cavity as an endogenous reservoir for gut microbial strains, and oral-fecal transmission as an important process that shapes the gastrointestinal microbiome in health and disease.

[Microflora in patients with systemic connective tissue diseases].

The study of microflora of skin, mucous tunic of nose and mouth, and the quantitative and qualitative structure of the intestinal and urinal microflora in cases of systemic connective tissues diseases, are reproduced. The decrease of the dominant state of typical representatives, and the increase of the role of pseudopathogenic bacteria in various biotypes, were observed. The frequency of S. aureus detection increased in skin, mucous tunic of nose and mouth. Pseudopathogenic microbes acquired greater significance in the forming of microbiocenosis of intestine, while the number of E. coli, Bifidobacterium and Lactobacterium decreased. The frequency of detection of microbes in urine decreased. The comparative analyses of the microflora in patients with systemic lupus erythromatosis and progressive systemic sclerosis demonstrated the common peculiarities for microflora character change.

Bacterial Fermentation of Water-Soluble Cellulose Acetate Raises Large-Bowel Acetate and Propionate and Decreases Plasma Cholesterol Concentrations in Rats.

We hypothesized that water-soluble cellulose acetate (WSCA) could be useful tool for the delivery of short-chain fatty acids to the large intestine. Rats were fed a control diet or a diet containing graded levels of WSCA for up to 21 days. Consuming WSCA dose-dependently increased large-bowel acetate and propionate concentrations through the bacterial fermentation. When WSCA was used as substrate, acetyl esterase activity in the cecal bacteria was detected solely in rats fed WSCA, in which the activity increased over time accompanied by an increased number of Bacteroides xylanisolvens. Consuming WSCA at a 4% level increased the goblet cell numbers and mucin contents in the cecum and lowered plasma cholesterol concentrations, which tended to correlate with the portal plasma concentrations of propionate. The results suggest that bacterial fermentation of WSCA is characterized by the greater production of acetate and propionate, which may contribute to the physiologic alterations.

Adding mucins to an in vitro batch fermentation model of the large intestine induces changes in microbial population isolated from porcine feces depending on the substrate.

Adding mucus to in vitro fermentation models of the large intestine shows that some genera, namely lactobacilli, are dependent on host-microbiota interactions and that they rely on mucosal layers to increase their activity. This study investigated whether this dependence on mucus is substrate dependent and to what extent other genera are impacted by the presence of mucus. Inulin and cellulose were fermented in vitro by a fecal inoculum from pig in the presence or not of mucin beads in order to compare fermentation patterns and bacterial communities. Mucins increased final gas production with inulin and shifted short-chain fatty acid molar ratios (P < 0.001). Quantitative real-time PCR analyses revealed that Lactobacillus spp. and Bifidobacterium spp. decreased with mucins, but Bacteroides spp. increased when inulin was fermented. A more in-depth community analysis indicated that the mucins increased Proteobacteria (0.55 vs 0.25%, P = 0.013), Verrucomicrobia (5.25 vs 0.03%, P = 0.032), Ruminococcaceae, Bacteroidaceae and Akkermansia spp. Proteobacteria (5.67 vs 0.55%, P < 0.001) and Lachnospiraceae (33 vs 10.4%) were promoted in the mucus compared with the broth, while Ruminococcaceae decreased. The introduction of mucins affected many microbial genera and fermentation patterns, but from PCA results, the impact of mucus was independent of the fermentation substrate.

Physiological implications of microbial digestion in the large intestine of mammals: relation to dietary factors.

The rate of digesta marker passage through the large intestine of the dog, pig, and pony correlated with the relative length and degree of sacculation of the colon. Volatile fatty acids (VFA), the end products of microbial digestion of all forms of carbohydrate, were the major anions present in large intestinal contents of all three species. Total VFA concentration was little affected by the feeding of high-versus low-fiber diets. VFA were rapidly transported across colonic mucosa of all three species. Results of comparative studies indicate that production and absorption of VFA are important to the nutrition of some mammals and to the normal secretory and absorptive functions of the large intestine of most mammals.

Diet and cell growth modulation by ammonia.

Fiber is not digested by endogenous enzymes but is fermented by microbes principally in the large intestine. With fermentable energy available, microbes synthesize protein by using ammonia released by their enzymes from urea and other nitrogenous substances in ingesta and intestinal secretions. Fibber fermentation also yields fatty acids that lower the concentration of free ammonia by lowering pH. Fiber increases bulk and water of intestinal contents, shortens transit time, and decreases the concentration of toxic substances in contact with the intestinal mucosa. These processes decrease duration and intensity of exposure of the intestinal mucosa to free ammonia, the form of nitrogen that is most toxic and most readily absorbed by cells. At concentrations found in the lower bowel on usual Western diets, ammonia destroys cells, alters nucleic acid synthesis, increases intestinal mucosal cell mass, increases virus infections, favors growth of cancerous cells over noncancerous cells in tissue culture, and increases virus infections. Ammonia in the bowel increases as protein intake increases. The attributes of ammonia and the epidemiological evidence comparing populations that maintain low intakes of unrefined carbohydrate with those that consume high intakes of protein, fat, and refined carbohydrates implicate ammonia in carcinogenesis and other disease processes.

Establishment of cellulolytic bacteria in the digestive tract of conventionally reared young mice: effect of the dietary cellulose content in the adult.

Cellulolytic bacteria became established 12 days after birth in the caecum and colon of conventionally-reared mice fed a diet containing 5 p. 100 crude cellulose (Weende). Their population reached a level between 10(6) and 10(7) bacteria per gram of digestive contents in 25-day-old animals. However, variations between animals were very large; 20 to 50% of the individuals were free of cellulolytic bacteria. A low cellulolytic population was observed in adult mice fed a cellulose-free diet. The amount of cellulose in the diet and its nature (crude or pure cellulose) affected the number of cellulolytic bacteria: the higher the percentage of cellulose in the diet, the higher the number of cellulolytic bacteria, in particular with crude cellulose-containing diet.

The distribution of the cariogenic bacterium Streptococcus mutans in the gastrointestinal tract of monkeys (Macaca fascicularis).

The success of oral vaccines based on Strep. mutans might be influenced by its presence in the gastrointestinal (GI) tract. Enumeration of Strep. mutans at various sites of the GI tract of sucrose-fed monkeys revealed a localized distribution. High numbers of Strep. mutans were recovered from only the dental plaque, caecum and the large intestine. Where Strep. mutans was not detectable in the dental plaque it could not be isolated from regions of the GI tract sampled. The absence of Strep. mutans from the small intestine suggests that the disparate results obtained from experiments in which this organism was used to immunize monkeys orally, are not attributable to the prior colonization of such an immunologically important region.

Colonization of intestinal bacteria in the normal neonate: comparison between mouth and rectal swabs and small and large bowel specimens.

Seventy-four New Zealand white rabbit pups were divided into four groups: group I, 2 days of age (n = 9); group II, 3 to 5 days of age (n = 24); group III, 6 to 8 days of age (n = 27); and group IV, 10 to 13 days of age (n = 14). Mouth swabs (MS), rectal swabs (RS), small bowel specimens (SB), and large bowel specimens (LB) were obtained from each rabbit, incubated for 24 hours in thioglycolate broth, and plated on blood agar in aerobic and anaerobic environments. After 24 hours, growth on blood agar plates were observed. All MS specimens and all but one RS specimen showed positive growth. Growth of both LB and SB specimens increased significantly with age (P < .04). In addition, SB growth was significantly less than RS or MS growth in groups I, II, and III (P < .05). LB growth was significantly less than RS or MS growth in group I (P < .01) and tended to be less in groups II and III (62.5% v 100% and 93% v 100%, respectively). These data show that nearly half of normal rabbits under 6 days of age have sterile small and large intestines despite almost 100% growth from rectal and mouth swabs. These findings partially explain the absence of spontaneous bacterial translocation in young rabbit pups (under 4 days of age) and have important implications for the prophylaxis and treatment of neonatal sepsis.

Experimental production of rabbit mucoid enteritis.

Rabbit mucoid enteritis (mucoid enteropathy) is a subacute fatal disease of weanling rabbits with unknown cause. Mucoid enteritis was experimentally produced by ligating the large intestines in rabbits. Of the rabbits with ligated cecum and those with ligated colon, 70% and 45%, respectively, had excessive production of mucus and passed large amounts of mucus with feces, closely resembling the naturally occurring mucoid enteritis. Injection of oxytetracycline into the cecum at the time of ligation prevented the development of mucoid enteritis, and injection of cholestyramine markedly reduced the frequency of the disease in the rabbits with ligated cecum.

Isolation and identification of strains of Bacteroides fragilis group from the digestive tract of Callithrix penicillata marmosets.

Thirty-five strains of the Bacteroides fragilis group were isolated from oral and intestinal samples from 5 wild caught, captive Callithrix penicillata. Nine oral strains of Bacteroides fragilis (7) and Bacteroides distasonis (2), and 26 intestinal strains of Bacteroides fragilis (14) and Bacteroides distasonis (12) were identified.

[A method of preparing the large intestine for surgery by using the peroral administration of a polyethylene oxide solution]. / Metod podgotovki tolstoi kishki k operatsii pomoshchi peroral'nogo vvedeniia rastvora poliétilenoksidov.

A new method for preparing the large intestine for operation is suggested, it is based on oral administration of a solution of polyethylene oxides with chloramphenicol. The preparation possesses a marked hydrophilic activity, which causes inhibition of absorption processes in the lumen of the intestinal tube. This leads to accumulation of the intestinal contents and their quicker passage. Polyethylene oxides also ensure accumulation of antibiotics in the tissues of the intestinal wall. The suggested method was used to prepare the intestine for operation in 93 patients. Comparative evaluation proved its advantages according to the main clinico-laboratory criteria: the method is technically simple, reduces the period of preparation of the intestine, has no negative effect on the homeostasis values, ensures adequate preparation of the large intestine with decrease of the level of its microbial contamination. With the use of the method the number of postoperative purulent complications in interventions on the large intestine reduced.

Cellulolytic bacteria from pig large intestine.

An anaerobic, cellulose-degrading, gram-negative rod and a gram-positive coccus, identified as Bacteroides succinogenes and Ruminococcus flavefaciens, respectively, were isolated from pig fecal samples. These organisms were isolated from cellulolytic most-probable-number dilutions which represented 4 or 6% of the viable bacterial count when pigs were fed a low- or high-fiber diet, respectively.