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PubMed1990

Influence of antibiotics on intestinal tract survival and translocation of environmental Pseudomonas species.

The environmental release of microorganisms has prompted the investigation of potential health effects associated with their release. In this study, survival and translocation to the spleen and liver of several environmental Pseudomonas spp. were investigated in antibiotic-treated mice. Pseudomonas aeruginosa BC16 and P. maltophilia BC6, isolated from a commercial product for polychlorinated biphenyl degradation; P. aeruginosa AC869, a 3,5-dichlorobenzoate degrader; and P. cepacia AC1100, an organism that metabolizes 2,4,5-trichlorophenoxyacetic acid were examined for their survival capabilities in the intestines of mice dosed with clindamycin, kanamycin, rifampin, or spectinomycin. A mouse intestinal isolate, strain PAMG, was included in the study. Following antibiotic pretreatment (1 mg twice daily for 3 days), mice were dosed by gavage with 10(9) CFU of each Pseudomonas strain. At the end of the 5-day test period, strains AC869 and PAMG survived in kanamycin-, rifampin-, spectinomycin-, and clindamycin-treated animals. A statistically significant (P less than 0.05) increase in survival of strain PAMG was observed in clindamycin-, kanamycin-, and spectinomycin-treated mice for the test period. Treatment with clindamycin or rifampin increased (P less than 0.05) survival of strain BC6, an organism resistant to both antibiotics. However, strain BC6 was detected only in rifampin-treated mice at the end of the 5-day test period. Strain BC16, a clindamycin-resistant strain, was detected in clindamycin-treated mice and the untreated control animals. Rifampin had a negative effect (P less than 0.05) on strain AC869 and PAMG survival. Translocation to the spleen was observed in spectinomycin- and clindamycin-treated mice but was not detected in kanamycin- or rifampin-treated animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2005

The effects of mycotoxins, fungal food contaminants, on the intestinal epithelial cell-derived innate immune response.

Mycotoxins are structurally diverse fungal metabolites that can contaminate a variety of dietary components consumed by animals and humans. It is considered that 25% of the world crop production is contaminated by mycotoxins. The clinical toxicological syndromes caused by ingestion of moderate to high amounts of mycotoxins and their effect on the immune system have been well characterized. However, no particular attention has been focused on the effects of mycotoxins on the local intestinal immune response. Because of their location, intestinal epithelial cells (IECs) could be exposed to high doses of mycotoxins. As a component of the innate local immune response, intestinal epithelial cells have developed a variety of mechanisms which act to reduce the risk of infection by microorganisms or intoxication by toxic compounds. This review summarises the innate immune response developed by intestinal epithelial cells and reports the literature concerning the effects of mycotoxins on them. Particularly, the effects of mycotoxins on the maintenance of a physical barrier by epithelial cells will be discussed together with their effect on extrinsic protective components of the innate intestinal immunity: mucus secretion, antimicrobial peptide generation, IgA and pro-inflammatory cytokine release.

Animals↗
PubMed2002

Some factors affecting the adherence of probiotic Propionibacterium acidipropionici CRL 1198 to intestinal epithelial cells.

Adhesion to the intestinal mucosa is generally considered an important property of probiotic microorganisms and has been related to many of their health benefits. This study investigated some factors that could affect or be involved in the adherence of Propionibacterium acidipropionici CRL 1198, a dairy strain with suggested probiotic effects and high adherence in vitro and in vivo to intestinal epithelial cells. In vitro adhesion of propionibacteria was decreased by gastric digestion but not affected by bile and pancreatic enzymes. Adherence was also decreased by pretreatment of bacterial cells with protease, sodium metaperiodate, and trichloroacetic acid, revealing that different features of the cell surface, like protein factors, carbohydrates, and teichoic acids, are involved in the process. Adherence to intestinal epithelial cells was enhanced by calcium and was dependent on other divalent cations. Adhesion to intestinal mucus was also demonstrated. The results should explain the metabolic effects in the host previously obtained with this strain and support the potential of Propionibacterium for development of new probiotics.

Animals↗
PubMed1999

Does probiotics administration decrease serum endotoxin levels in infants?

PURPOSE: The aim of this study was to examine whether administration of probiotics to infants can change the ratio of intestinal flora and thereby decrease serum endotoxin produced by potentially pathogenic microorganisms. METHODS: Nine infants including five with of biliary atresia, two with omphalocele, one each with Hirschsprung's disease and imperforate anus were studied. All patients were stable, and no antibiotics were given during this study. A probiotic mixture consisting of Streptococcus faecalis, Clostridium butyricum and Bacillus mesentericus was administered orally to each infant at 2 g/day for 2 weeks. Fecal aerobic and anaerobic bacterial cultures, serum endotoxin level, and other biochemical parameters were examined. RESULTS: In fecal cultures, anaerobic bacteria including Bifidobacterium increased significantly whereas Escherichia coli, Streptococcus, and Klebsiella tended to decrease. The ratio of anaerobic to aerobic bacteria increased five times as a result of administration of probiotics, and serum endotoxin levels decreased. CONCLUSIONS: Probiotics affect intestinal bacterial flora by increasing anaerobic bacteria and decreasing the population of potentially pathogenic microorganisms. A decrease in luminal endotoxin may result in less endotoxin translocation or bacterial translocation.

Administration, Oral↗
PubMed1975

Effect of microflora on the free amino acid distribution in various regions of the mouse gastrointestinal tract.

The distribution of free amino acids in the contents of various regions of the gastrointestinal tract (stomach, upper small intestine, lower small intestine, cecum, upper colon and lower colon) was studied in germfree and conventionalized mice. Particular emphasis was placed on the conversion of tryptophan to indole as a probe for studying intermicrobial interactions and microbe-host interactions in vivo. Great differences were observed in the free amino acid content of the various regions of the digestive tract in each type of mouse and also in any one region between germfree and conventionalized mice. As would be expected, there were fewer differences in amino acid distribution between the types of mice in both regions of the small intestine. This correlates with a much lower population of microorganisms in these regions. The changes in free amino acid content and distribution produced by microflora are great enough to serve as a good probe for studying the interactions of a limited number of species of microbes in gnotobiotic animals and assign possible specific functions to each species.

Amino Acids↗
PubMed2001

[Intestinal tuberculosis: Easier overlooked than diagnosed].

Intestinal tuberculosis: Easier overlooked than diagnosed. The medical history of two Asian immigrants suffering from intestinal tuberculosis demonstrates the difficulties in finding the correct diagnosis. Intestinal tuberculosis resembles Crohn's disease with regard to clinical symptoms, macroscopic and microscopic intestinal findings. Sonographic, radiologic, endoscopic, and histological examinations facilitate distinguishing both entities. Diagnosis of intestinal tuberculosis is made by identification of the causative microorganism in tissue specimens. As this may be difficult and time-consuming, a therapeutic trial with anti-tuberculous agents may be warranted.

Adult↗
PubMed2002

How host-microbial interactions shape the nutrient environment of the mammalian intestine.

Humans and other mammals are colonized by a vast, complex, and dynamic consortium of microorganisms. One evolutionary driving force for maintaining this metabolically active microbial society is to salvage energy from nutrients, particularly carbohydrates, that are otherwise nondigestible by the host. Much of our understanding of the molecular mechanisms by which members of the intestinal microbiota degrade complex polysaccharides comes from studies of Bacteroides thetaiotaomicron, a prominent and genetically manipulatable component of the normal human and mouse gut. Colonization of germ-free mice with B. thetaiotaomicron has shown how this anaerobe modifies many aspects of intestinal cellular differentiation/gene expression to benefit both host and microbe. These and other studies underscore the importance of understanding precisely how nutrient metabolism serves to establish and sustain symbiotic relationships between mammals and their bacterial partners.

Animals↗
PubMed1984

Microvilli- and desmosome-associated bodies in Crohn's disease and other disorders in childhood: an ultrastructural abnormality of the small and large intestine.

Ultrastructural studies of the small and large intestine from children revealed five cases showing abnormal small electron-dense bodies within enterocytes and goblet cells. The characteristic features of the bodies were: (a) they occurred within microvilli and within the apical part of the cell cytoplasm; (b) they showed an association with the most apically located desmosomes of the epithelial cells; (c) in the microvilli they were present within protrusions of the membrane, suggesting that they may bud out of the cell; and (d) they were not membrane-bound within the cell but were found outside the cell as luminal, membrane-bound particles. These bodies occurred in two children with Crohn's disease and in three children having other gastrointestinal disorders. Similar electron-dense bodies which did not have all of the characteristics listed above were found in a sixth child who had Crohn's disease. These electron-dense bodies do not resemble any known inclusion of intestinal epithelium, nor do they resemble any previously described microorganism, although their apparent release from the cell by a process of budding is suggestive of a microbial identity. The occurrence of these bodies in childhood Crohn's disease suggests that they may be disease-related, but their precise nature and relevance to this or other gastrointestinal disorders remain unknown.

Adolescent↗
PubMed1991

Effect of loracarbef on the normal oropharyngeal and intestinal microflora.

20 healthy volunteers received loracarbef capsules 200 mg b.i.d. for 7 days. Saliva and stool specimens were taken before loracarbef administration and on the 2nd, 5th, and 7th day during the administration period, and again 2, 5 and 9 days after withdrawal of the antibiotic to study the effect of loracarbef on the normal microflora. The concentrations of loracarbef in serum, saliva and faeces were determined by an agar diffusion method. The mean serum peak concentration attained after 1 h was 6.8 mg/l and the saliva concentrations were in the range 0-0.9 mg/l. The loracarbef concentrations in faeces ranged from 0 to 0.9 mg/kg. The changes in the the oropharyngeal microflora were minor and only bacteroides rods were affected. In the intestinal aerobic microflora, the number of enterococci and streptococci slightly increased while staphylococci, micrococci, corynebacteria, bacillus and enterobacteria were not affected. The number of bifidobacteria and eubacteria in the anaerobic microflora decreased while no other bacterial groups were affected. One week after withdrawal of loracarbef, both the oropharyngeal and intestinal microflora had returned to normal. No new colonizing loracarbef resistant microorganisms were observed during the investigation period.

Administration, Oral↗
PubMed1999

Study of infectious intestinal disease in England: rates in the community, presenting to general practice, and reported to national surveillance. The Infectious Intestinal Disease Study Executive.

OBJECTIVE: To establish the incidence and aetiology of infectious intestinal disease in the community and presenting to general practitioners. Comparison with incidence and aetiology of cases reaching national laboratory based surveillance. DESIGN: Population based community cohort incidence study, general practice based incidence studies, and case linkage to national laboratory surveillance. SETTING: 70 general practices throughout England. PARTICIPANTS: 459 975 patients served by the practices. Community surveillance of 9776 randomly selected patients. MAIN OUTCOME MEASURES: Incidence of infectious intestinal disease in community and reported to general practice. RESULTS: 781 cases were identified in the community cohort, giving an incidence of 19.4/100 person years (95% confidence interval 18.1 to 20.8). 8770 cases presented to general practice (3.3/100 person years (2.94 to 3.75)). One case was reported to national surveillance for every 1.4 laboratory identifications, 6.2 stools sent for laboratory investigation, 23 cases presenting to general practice, and 136 community cases. The ratio of cases in the community to cases reaching national surveillance was lower for bacterial pathogens (salmonella 3.2:1, campylobacter 7.6:1) than for viruses (rotavirus 35:1, small round structured viruses 1562:1). There were many cases for which no organism was identified. CONCLUSIONS: Infectious intestinal disease occurs in 1 in 5 people each year, of whom 1 in 6 presents to a general practitioner. The proportion of cases not recorded by national laboratory surveillance is large and varies widely by microorganism. Ways of supplementing the national laboratory surveillance system for infectious intestinal diseases should be considered.

Adolescent↗
PubMed1995

Segmented filamentous bacteria are indigenous intestinal bacteria that activate intraepithelial lymphocytes and induce MHC class II molecules and fucosyl asialo GM1 glycolipids on the small intestinal epithelial cells in the ex-germ-free mouse.

In ex-germ-free mice conventionalized by association with fecal microorganisms, the induction fo major histocompatibility complex class II molecules and fucosylation of asialo GM1 glycolipid occur in the small intestinal epithelial cells (IEC). The intestinal intraepithelial lymphocytes (IEL), especially alpha beta T-cell receptor-bearing ones, also remarkably expand and show cytolytic activity. In this study, we investigated the immunological and physiological characteristics of the small intestine induced by a kind of indigenous bacteria of the small intestine, segmental filamentous bacteria (SFB), among chloroform-resistant intestinal bacteria. Monoassociation of SFB with germ-free mice was confirmed by the determination of the base sequences of polymerase chain reaction products of 16S rRNA genes of the fecal bacteria of these mice and in situ hybridization using fluorescein-labeled probes based on them. SFB increased the number of alpha beta TCR-bearing IEL and induced Thy-1 expression and cytolytic activity of IEL. The induction of MHC class II molecules and fucosyl asialo GM1 glycolipids and the increases in the mitotic activity and the ratio of the number of columnar cells to those of goblet cells also occurred in the small intestinal epithelial cells on monoassociation of these bacteria. SFB are important indigenous bacteria for the development of the mucosal architecture and immune system in the small intestine, at least in mice.

Animals↗
PubMed1989

Binding and transepithelial transport of immunoglobulins by intestinal M cells: demonstration using monoclonal IgA antibodies against enteric viral proteins.

M cells of intestinal epithelia overlying lymphoid follicles endocytose luminal macromolecules and microorganisms and deliver them to underlying lymphoid tissue. The effect of luminal secretory IgA antibodies on adherence and transepithelial transport of antigens and microorganisms by M cells is unknown. We have studied the interaction of monoclonal IgA antibodies directed against specific enteric viruses, or the hapten trinitrophenyl (TNP), with M cells. To produce monospecific IgA antibodies against mouse mammary tumor virus (MMTV) and reovirus type 1, Peyer's patch cells from mucosally immunized mice were fused with myeloma cells, generating hybridomas that secreted virus-specific IgA antibodies in monomeric and polymeric forms. One of two anti-MMTV IgA antibodies specifically bound the viral surface glycoprotein gp52, and 3 of 10 antireovirus IgA antibodies immunoprecipitated sigma 3 and mu lc surface proteins. 35S-labeled IgA antibodies injected intravenously into rats were recovered in bile as higher molecular weight species, suggesting that secretory component had been added on passage through the liver. Radiolabeled or colloidal gold-conjugated mouse IgA was injected into mouse, rat, and rabbit intestinal loops containing Peyer's patches. Light microscopic autoradiography and EM showed that all IgA antibodies (antivirus or anti-TNP) bound to M cell luminal membranes and were transported in vesicles across M cells. IgA-gold binding was inhibited by excess unlabeled IgA, indicating that binding was specific. IgG-gold also adhered to M cells and excess unlabeled IgG inhibited IgA-gold binding; thus binding was not isotype-specific. Immune complexes consisting of monoclonal anti-TNP IgA and TNP-ferritin adhered selectively to M cell membranes, while TNP-ferritin alone did not. These results suggest that selective adherence of luminal antibody to M cells may facilitate delivery of virus-antibody complexes to mucosal lymphoid tissue, enhancing subsequent secretory immune responses or facilitating viral invasion.

Animals↗
PubMed2001

Lactic acid bacteria and their effect on the immune system.

Lactic acid bacteria (LAB) are present in the intestine of most animals. The beneficial role played by these microorganisms in the humans and other animals, including the effect on the immune system, has been extensively reported. They are present in many foods and are frequently used as probiotics to improve some biological functions in the host. The activation of the systemic and secretory immune response by LAB requires many complex interactions among the different constituents of the intestinal ecosystem (microflora, epithelial cells and immune cells). Through different mechanisms they send signals to activate immune cells. Thus the knowledge of the normal intestinal microflora, the contribution of LAB and their role in the numerous functions in the digestive tract as well as the functioning of the mucosal immune system form the basis for the study and selection of a probiotic strain with immunostimulatory properties. In the selection of LAB by their immunostimulatory capacity it helps to know not only the effect which they have on the mucosal immune system, but the specific use to which these oral vaccine vectors are being put. Although there are reports of the protection of animals and humans against diseases such as microbial infections and cancer, more work remains to be done on the factors affecting the design of oral vaccine vectors and the use of LAB for therapeutic purposes. The basic knowledge of LAB immunostimulation and the criteria for selection of LAB by their immunostimulatory capacity, will be extensively discussed and appraised in this review.

Animals↗
PubMed1999

[Incidence of Plesiomonas shigelloides in tilapia tetrahibrids (Oreochromis sp.)].

Plesiomonas shigelloides, a member of the family Vibrionaceae, is a Gram negative rod associated with several gastroenteritis outbreaks, especially in tropical and subtropical countries. In same way, it has been related to some septicemia, meningitis and cholecystitis cases. The microorganism is normally found in water, fish and birds. The aim of this work was to study the incidence of Plesiomonas shigelloides in tetrahybrids of Oreochromis sp. (Pink Tilapia) located at the central region of Venezuela. Once the samples were homogenized, the techniques of enrichment and direct streaking were used simultaneously for the isolation of the microorganism. A high incidence of P. shigelloides was determined (73%), being higher in the intestinal tract (60%), followed by the skin (36.7%) and the gills (26.67%), without any correlation among them. In the fish pond, the microorganism isolation frequency was 41.67%. The direct streaking technique presented the highest isolation values in the different Tilapia tissues (60%) and in the water as well (41.60%). No significant differences were observed on the effectivity of the selective agars used for the isolation of P. shigelloides (Plesiomonas Agar and Inositol-Brilliant Green-Bile Salts Agar). A positive correlation was observed between the microorganism incidence and the pluviosity levels. A high incidence of E. coli was observed in the samples of Tilapia tissues and the water pond. No correlation was observed between incidence of P. shigelloides and E. coli. Due to the high prevalence of P. shigelloides found in the present study, it is important to assure a proper evisceration, washing and storage at temperatures lower than 8 degrees C, and a proper product cooking to diminish the customeris risk.

Animals↗
PubMed1992

[Enzymes and histology of the intestinal mucosa of breast-fed African infants].

Weight gain and statural growth are slow in the Kivu area (Zaïre), as compared with international reference curves. One hypothesis put forward to explain this well-documented but poorly understood fact is inadequate breast-feeding with early intake of foods responsible for the introduction of microorganisms with deleterious effects on the digestive tract. A study of intestinal mucosa specimens from 90 at least partially breast-fed infants (4 to 22 months) showed that the appearance of the jejunal mucosa was consistently abnormal, as compared with histologic standards used in Europe. Furthermore, intestinal disaccharidase activities were always abnormal; lactase activities were extremely low and alpha-glucosidase activities were reduced by one-third to one-half as compared with European reference values. Age apparently influenced the magnitude of these modifications, whereas the correlation with nutritional status was less clear; only a correlation between the serum albumin level and the microscopic appearance of jejunal biopsy specimens was found. Intestinal alpha-glucosidase levels were lower in those patients with giardiasis. These findings demonstrate that in Kivu early atrophy of the intestinal mucosa contributes, together with the protein-calory malnutrition, to the lower growth rates in infants.

Age Factors↗
PubMed2006

Multiparameter analysis of immunogenetic mechanisms in clinical diagnosis and management of inflammatory bowel disease.

The integrity of the intestinal mucosa depends on a functional coordination of the epithelium, lumenal microorganisms, and the local immune system. The mammalian immune system is superbly organized for innate and adaptive recognition of microbial antigens, a defensive capacity that must be balanced against the tissue damage produced by immune activity to preserve normal intestinal function. Inflammatory bowel disease (IBD) is generally thought to reflect an impairment in this balance, due to a combination of host genetic traits that shift the balance of immune and epithelial function to commensal microbiota, and perhaps the composition or activity of certain microbial elements as well. There has been much progress defining the fundamental disorders of these host traits, immunologic processes, and microbial targets in inflammatory bowel disease. Other fields of clinical and geologic microbiology are teaching us about the dynamic interaction of commensal bacteria with their host environment. These lines of investigation have revealed not only important insights about inflammatory bowel disease (IBD) pathogenesis, but also defined technologies and tools useful for its diagnosis and clinical management. This review focuses on these advances at the translational interface. We will first consider the innate anti-microbial response, centering on the utility of NOD2 genotyping for predicting disease susceptibility, prognosis, and therapeutic response profile. We will then turn to the adaptive anti-microbial response, focusing on the application of antibodies to fungal and bacterial species and products for Crohn's disease (CD) diagnosis and prognosis, and immunogenetics of T cell immunosuppression management. Finally, we will describe autoimmune mechanisms in IBD, with particular attention to autoantibodies in IBD diagnosis and infliximab responsiveness. We will conclude with the concept of multiparameter analysis of patients, to refine patient characterization and stratification in diagnosis and clinical management.

Animals↗
PubMed2000

Systemic bacterial invasion induced by sleep deprivation.

Profound sleep disruption in humans is generally believed to cause health impairments. Through comparative research, specific physical effects and underlying mechanisms altered by sleep deprivation are being elucidated. Studies of sleep-deprived animals previously have shown a progressive, chronic negative energy balance and gradual deterioration of health, which culminate in fatal bloodstream infection without an infectious focus. The present study investigated the conditions antecedent to advanced morbidity in sleep-deprived rats by determining the time course and distribution of live microorganisms in body tissues that are normally sterile. The tissues cultured for microbial growth included the blood, four major organs, six regional lymph nodes, the intestine, and the skin. The principal finding was early infection of the mesenteric lymph nodes by bacteria presumably translocated from the intestine and bacterial migration to and transient infection of extraintestinal sites. Presence of pathogenic microorganisms and their toxins in tissues constitutes a septic burden and chronic antigenic challenge for the host. Bacterial translocation and pathogenic sequelae provide mechanisms by which sleep deprivation appears to adversely affect health.

Animals↗
PubMed1993

The effect of antimicrobial agents on the ecology of the human intestinal microflora.

The most common and significant cause of disturbances in the normal intestinal microflora is the administration of antimicrobial agents. The microflora can be influenced by antimicrobial agents because of incomplete absorption of any orally administered antimicrobial agent, secretion of an antimicrobial agent in the bile, or secretion from the intestinal mucosa. Administration of these agents may seriously disturb the balance of the normal intestinal microflora. This disturbance can cause bacterial overgrowth and emergence of resistant microorganisms which may lead to serious infections and also encourage transfer of resistance factors among bacteria. The ecological effects of penicillins, cephalosporins, monobactams, carbapenems, macrolides, clindamycin, tetracyclines, nitroimidazoles and quinolones on the human intestinal microflora are presented in this review article.

Anti-Bacterial Agents↗