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PubMed2003

[Clinical significance of studies of microorganisms of the intestinal mucosa by culture biochemical methods and mass fragmentography].

This research is a continuation of the series of studies of the parietal microbiota of the bowel tissue samplings by the gas chromatography and mass spectrometry (GCMS) method [G.A. Ossipov et al.//Journal of the Society of Russian Gastroenterologists, 2001, 1:54-69]. The purpose was to study a number of new microorganisms in view of new data on the composition of their fatty acids (FA) and aldehydes; to confirm the presence of a number of bacteria, fungi and aerobic actinomycetes revealed earlier by FA markers in the composition of the bowel parietal microbiota by their isolation in a pure culture; to amend the estimation of the clinical value of changes in the composition of the human bowel parietal microflora in case of irritable bowel syndrome (IBS) and antibiotics-associated diarrhea (AAD). We examined 31 patients with IBS with predominating diarrhea, 18 patients with AAD and 3 volunteers (a control group). We studied the blood samples, tissue samplings of the mucous coat of the jejunum, ileum and colon and composition of healthy people's feces. The GCMS method was applied. Morphology of defined strains was controlled by methods of light and scanning electron microscopy. We found a substantial portion of eubacteria among the bowel microorganisms and specific changes of their species in case of IBS and AAD. Taking into account their physiological and biochemical activity, when regulating their concentration one can expect at least the same effect as when regulating the number of bifidobacteria and lactobacilli in treatment of intestinal pathologies and other diseases related to bowel dysbacteriosis. The analysis of the feces microbiota using the GCMS method by FA of parietal microorganisms provides reliable data on their number both in feces and in tissue samplings. We found a substantial portion of eubacteria among other bowel microorganisms (27% in the jejunum and 16% in the colon) and specific changes of their species in case of IBS and AAD. The concentration of streptomycetes, rhodococci and other members of the Actinomycetales order becomes dozens times more and/or reduces in pathological states. The tenfold concentration of markers of lactobacilli and bifidobacteria in some diseases stimulates the differentiated application of widespread probiotics based on these bacteria.

Bacteria↗
PubMed2004

Effect of Lactobacillus F19 on the emergence of antibiotic-resistant microorganisms in the intestinal microflora.

OBJECTIVES: Probiotic lactic-acid-producing bacteria have been used for prevention of gastrointestinal diseases. The aim of the present study was to examine whether Lactobacillus F19 in conjunction with treatment with penicillin, ciprofloxacin or norfloxacin prevents establishment of resistant bacteria in the gastrointestinal tract. METHODS: Twenty patients admitted to hospital due for treatment with penicillin and 16 patients due for treatment with ciprofloxacin or norfloxacin were included in the study. In either group, the patients were randomized into two groups, receiving placebo or an active probiotic product. Faecal samples were collected before treatment, on day 10 and 1 month after the start of the treatment. Isolates of enterococci, enterobacteria and Bacteroides fragilis species were screened for resistance to penicillin and ciprofloxacin, respectively. RESULTS: Administration of penicillin did not influence resistance in enterococci while quinolone resistance increased during quinolone treatment. Susceptibility to ampicillin and piperacillin/tazobactam decreased in enterobacteria during penicillin treatment and ciprofloxacin resistance increased in the quinolone group. Penicillin and quinolones did not influence the resistance rates of Bacteroides isolates. No major differences were observed between the probiotic- and placebo-supplemented groups. CONCLUSIONS: There was a limited effect of Lactobacillus F19 on the emergence of resistant isolates during treatment with penicillin and quinolones.

Adolescent↗
PubMed2002

Transfer of the pheromone-inducible plasmid pCF10 among Enterococcus faecalis microorganisms colonizing the intestine of mini-pigs.

A new animal model, the streptomycin-treated mini-pig, was developed in order to allow colonization of defined strains of Enterococcus faecalis in numbers sufficient to study plasmid transfer. Transfer of the pheromone-inducible pCF10 plasmid between streptomycin-resistant strains of E. faecalis OG1 was investigated in the model. The plasmid encodes resistance to tetracycline. Numbers of recipient, donor, and transconjugant bacteria were monitored by selective plating of fecal samples, and transconjugants were subsequently verified by PCR. After being ingested by the mini-pigs, the recipient strain persisted in the intestine at levels between 10(6) and 10(7) CFU per g of feces throughout the experiment. The donor strain, which carried different resistance markers but was otherwise chromosomally isogenic to the recipient strain, was given to the pigs 3 weeks after the recipient strain. The donor cells were initially present in high numbers (10(6) CFU per g) in feces, but they did not persist in the intestine at detectable levels. Immediately after introduction of the donor bacteria, transconjugant cells appeared and persisted in fecal samples at levels between 10(3) and 10(4) CFU per g until the end of the experiment. These observations showed that even in the absence of selective tetracycline pressure, plasmid pCF10 was transferred from ingested E. faecalis cells to other E. faecalis organisms already present in the intestinal environment and that the plasmid subsequently persisted in the intestine.

Animals↗
PubMed1975

[Polyamines in species of microorganisms of the intestinal group].

A study was made of polyamines (putrescine, spermidine and spermin) in various representatives of the Enterobacteriaceae family--E. coli, Sh, sonnei, Sh. flexneri and S. typhi abdominalis. All the strains under study contained putrescine and spermidine, and many Shigella and Salmonella strains had spermin in addition. There were significant differences in the quantitative content of polyamines in the individual species. By the ratio of nitrogen of polyamine to phosphorus of nucleic acid it is possible to assess the correlation in the content of polyamines and nucleic acids in the bacterial cells.

DNA, Bacterial↗
PubMed2003

An in vitro study on the active conversion of flucytosine to fluorouracil by microorganisms in the human intestinal microflora.

BACKGROUND: Investigation of the rate of active conversion of flucytosine to fluorouracil by microorganisms in the intestinal microflora. METHODS: Active conversion of flucytosine was investigated using viable and nonviable Escherichia coli at different flucytosine concentrations. Additionally, flucytosine conversion was studied in fecal specimens from 3 neutropenic patients at the start of the antimicrobial/antifungal prophylaxis (C/A regimen) and 1 week later. RESULTS: Flucytosine levels decreased by an average of 72, 71 and 72% flucytosine after incubation for 48 h of 10(10) viable E. coli /ml suspension in broth containing 13, 130 and 1300 mg/l flucytosine, respectively. The decreasing flucytosine levels corresponded approximately to an identical increase in fluorouracil levels. Also, a 44% decrease of flucytosine levels occurred when nonviable E. coli were used, indicating that bacterial viability is not necessary for this conversion. When fecal specimens of 2 patients were investigated prior to the C/A regimen, significant flucytosine conversion occurred, whereas this conversion was not observed in the corresponding fecal specimens after 1 week of C/A regimen. CONCLUSION: These in vitro experiments showed that extensive flucytosine conversion can occur in the human intestinal microflora by E. coli. Consequently, fluorouracil exposure and fluorouracil-related toxicity may occur in the flucytosine-treated patient.

Antifungal Agents↗
PubMed1979

A novel technique for detecting IgA coated potentially pathogenic microorganisms in the human intestine.

This paper describes a novel method for detecting immunoglobulin A (IgA) coated potentially pathogenic microorganisms (PPMs) in the human intestine. Essentially, the technique consists of 2 phases: one in which IgA coated bacteria are detected by immunofluorescence and a second in which these bacteria are subcultured in situ and subsequently identified. In this way transient bacteria are differentiated from resident bacteria. These results show that the resident bacteria are coated with IgA. Resident microorganisms are always highly concentrated in the digestive tract. These results strengthen the hypothesis that only the high antigen concentrations achieved by a large number of resident bacteria are capable of IgA induction.

Antibodies, Bacterial↗
PubMed1987

Activity of fiber-degrading microorganisms in the pig large intestine.

The large intestine is comparable to the rumen fermentation in many aspects; however, it is understood less well. Fiber in the form of cellulose and hemicellulose is one of the major substrates fermented in the large intestine. Various studies suggest that the pig can utilize fiber for growth, and up to 30% of its maintenance energy may be derived from volatile fatty acids produced in the large intestine. The total number of microorganisms in the pig large intestine do not change when a high fiber diet such as 50 or 80% alfalfa meal is fed. However, the fiber-degrading organisms increase and obviously replace others. The increase in fibrolytic bacteria normally coincides with an increase in enzyme activity (cellulase and xylanase), indicating that diet can be used to enhance fibrolytic activity. This is true for growing pigs and adult animals. The cellulolytic organisms in the pig, Bacteroides succinogenes and Ruminococcus flavefaciens, are similar to those in the rumen and are present at comparable numbers. This partly explains why adult pigs can maintain themselves by merely grazing on forage in pastures. Assuming other conditions are met, there is a significant potential for fiber degradation in the pig large intestine. Whether various genotypes such as the genetically selected obese and lean pigs have different abilities to degrade fiber is unknown. More work is required to understand the interaction of the fibrolytic organisms with the other organisms present in the large intestine, similar to that which has been done in the rumen, as well as the microbe-host interaction.

Animals↗