Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “INTESTINAL MICROORGANISMS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,045 records · Page 58Linked to original sources
PubMed1983

Local and systemic immune responses to intestinally presented antigen.

We have investigated the ability of the gut-associated lymphoid tissues (GALT) to react against standard antigens presented via different routes of administration. When antigens were presented directly to GALT, either by an injection into the Peyer's patches or via a mechanically damaged lamina propria, a rapid and vigorous immune response ensued. This was manifested systemically as an antigen-specific humoral antibody response in the serum and locally as an antigen-specific immunoglobulin A response in the bile. These results indicate that GALT is capable of reacting to foreign materials penetrating the gut wall. Additional experiments demonstrated that the extended feeding of degraded iota carrageenan, a material known to produce non-specific mucosal inflammation, caused GALT to react to antigenic molecules present within the gastro-intestinal tract and enhanced both serum and biliary antibody responses against specific gut commensal microorganisms. The immunological significance of these observations is discussed.

Administration, Oral↗
PubMed1992

Role of human microflora in health and disease.

The human host and its microbial flora constitute a complex ecosystem whose equilibrium serves as a remarkable example of reciprocal adaptation. Intestinal bacteria play an important role in the development of the immune system. The normal intestinal flora is responsible for resistance to colonization by exogenous pathogenic microorganisms. Nevertheless, it also constitutes a reservoir of potentially pathogenic bacteria in close contact with the host. These bacteria are responsible for opportunistic infections in immunocompromised hosts. The equilibrium of the flora can be upset by antibiotics, leading to infections as a result of proliferation of antibiotic-resistant pathogenic bacteria.

Animals↗
PubMed1994

Protein tyrosine kinase inhibitors block the entries of Listeria monocytogenes and Listeria ivanovii into epithelial cells.

The internalization of Listeria by intestinal epithelial cells is still poorly understood, however it is becoming apparent that microorganisms have developed the ability to interact with host cell receptor molecules to induce their own internalization. In this report we show that inhibition of cell tyrosine phosphorylation by protein tyrosine kinase (PTK) inhibitors blocks L. monocytogenes entry into both finite and immortalized intestinal cell lines. Some differences were observed between the Listeria species. L. monocytogenes entry was inhibited by between 10- to 100-fold by PTK inhibitors competing with the tyrosine residue binding of the kinase as erbstatin or by PTK inhibitors competing with the binding of ATP to the enzyme as genistein and some tyrphostins. On the other hand, L. ivanovii entry was inhibited by erbstatin as observed with L. monocytogenes but poorly by genistein and tyrphostins. The use of these several PTK inhibitors shows that even though both L. monocytogenes and L. ivanovii entered intestinal and other cell lines by stimulating PTK, it seems that L. monocytogenes stimulated a different PTK than L. ivanovii. According to the fact that the number of PTK receptors increases on immortalized cells, the higher L. monocytogenes internalization observed with immortalized cell lines could be related to a higher PTK receptor number on these cells compared to finite cell lines.

Animals↗
PubMed1998

Acacia gum (Gum Arabic): a nutritional fibre; metabolism and calorific value.

Gum Arabic (Acacia gum, INS 414: E414) is extensively used as a food additive, but there is no regulatory or scientific consensus about its calorific value. It is a complex polysaccharide, primarily indigestible to both humans and animals, not degraded in the intestine, but fermented in the colon under the influence of microorganisms. Despite a range of animal studies, there are no usable data for humans which can quantify the utilizable energy of Gum Arabic. Estimates in the literature from animal experiments vary from 0 to 4 kcal/g. After certain allowances are made for the energy losses from volatile and gaseous fermentation products, an upper level of 2 kcal/g for rats has been set. The situation in man is demonstrably different, with greatly reduced amounts of such products, and the need to adapt for varying periods before Gum Arabic is attacked by colonic bacteria. In the absence of an agreed scientific assignment, the FDA in the USA insist upon 4 kcal/g in nutritional labelling, whereas in Europe, no value has been assigned to soluble dietary fibre, such as Gum Arabic. This review argues that based on present scientific knowledge only an arbitrary value can be used for regulatory purposes.

Animals↗
PubMed2005

Gastric juice: a barrier against infectious diseases.

All vertebrates produce gastric acid. Its main function is inactivation of ingested microorganisms. The majority of microbiological pathogens ingested never reaches the intestine because of the gastric barrier. Although gastric hypochlorhydria is fairly common due to atrophic gastritis, gastric surgery or use of inhibitors of gastric acid secretion, the resulting susceptibility to infection has not been studied extensively. Drug-induced blockade of acid secretion leads to gastrointestinal bacterial overgrowth; the clinical significance of this is still controversial. Gastric acidity is known to protect against non-typhoid salmonellosis and cholera and it is suspected that it protects against several parasitic diseases as giardiasis and strongyloides. There is a lack of studies focusing on the impact of the gastric acidic barrier on viral infections. Concerning prion infections only a single study has been performed, demonstrating a possible role of gastric acidity in the protection against foodborne prion disease in mice. The combination of malnutrition and hypochlorhydria may contribute to the high prevalence of gastrointestinal infections in developing countries. Further studies are needed to evaluate the clinical consequences of impaired gastric acidity with respect to susceptibility to infections.

Animals↗
PubMed2003

Prevalence of Campylobacter within a swine slaughter and processing facility.

In this work, the occurrence of Campylobacter in a swine slaughter and processing facility was studied. Thirty composite carcass samples, representing 360 swine carcasses, were taken immediately after exsanguination, immediately after polishing, after the final wash, and after overnight chilling at 2 degrees C. Thirty matching composite rectal samples were also taken immediately after exsanguination, and 60 nonmatching individual colon samples were collected from the same lot of swine during evisceration. Also, 72 environmental samples were collected from equipment used in the slaughter operation (42 samples) and the processing operation (30 samples). Campylobacter was isolated by direct plating on Campy-Line agar (CLA) or Campy-Cefex agar (CCA), as well as by Bolton broth enrichment and subsequent inoculation onto CLA or CCA. For all four recovery methods combined, Campylobacter was detected on 33% (10 of 30) of the composite carcasses immediately after exsanguination, 0% (0 of 30) after polishing, 7% (2 of 30) immediately before chilling, and 0% (0 of 30) after overnight chilling. The pathogen was recovered from 100% (30 of 30) of the composite rectal samples and 80% (48 of 60) of the individual colon samples. Campylobacter was detected in 4.8% (2 of 42) and 3.3% (1 of 30) of the slaughter and processing equipment samples, respectively. The recovery rate achieved with direct plating on CLA was significantly higher (P < 0.05) than those achieved with the other three recovery methods. For the 202 isolates recovered from all of the various samples tested, Campylobacter coli was the predominant species (75%) and was followed by Campylobacter spp. (24%) and Campylobacter jejuni (1%). These results indicate that although Campylobacter is highly prevalent in the intestinal tracts of swine arriving at the slaughter facility, this microorganism does not progress through the slaughtering operation and is not detectable on carcasses after overnight chilling.

Abattoirs↗
PubMedDate not supplied

[Blastocystis hominis in patients at the Ruiz y Paez University Hospital from Bolivar City, Venezuela].

Blastocystis hominis is a polymorphic protozoan of discussed taxonomic position, which is currently associated with human intestinal disease. In order to determine the prevalence of the microorganism in a sample of hospitalized patients, a study was carried out from november 1996 to april 1997 on 100 adult patients of both sexes aged 20 to 79 years at the "Ruíz y Páez" University Hospital of Bolivar city, Venezuela. A coproparasitological study was carried out using direct examination and Faust method. Infection by parasites and/or commensals was demonstrated in 48 patients. The most frequent agent was B. hominis with a prevalence of 42.0%. We did not find a statistically association between sex (P > 0.05) or age (X2 = 3.52; d.f; = 3) and B. hominis infection. B. hominis was most frequently identified as the single parasite (88.1%), and with a number of less than 5 cells per 400X microscopic field (73.8%). The infection was more common in patients with base chronic-immunosuppressive diseases, the major one being cancer. Diarrhea was observed in 27.0% of cases. Due to its high prevalence, especially as a single agent, together with the particular immunological characteristics of the patients studied, a potential pathogenic role of the opportunistic type is suggested for B. hominis.

Adult↗
PubMedDate not supplied

[The identification of freshly isolated strains, the causative agents of human candidiasis and the search for effective antifungal probiotics].

The species variety of yeasts of the genus Candida in children and patients with AIDS has been investigated. Composition of the studied species was found to be similar in newborns and in women with candidiasis. In order to create new probiotics with antifungal properties, the cluster analysis of antagonistic activity of some Bacillus strains against Enterobacteriaceae, Candida, normoflora and food-fermenting lactobacteria has been conducted. There were selected the combinations of some Bacillus strains, which effectively inhibited pathogenic and opportunistic microorganisms and at the same time had no effect on intestinal normoflora.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

[The contamination of enteral nutrition in critical patients].

Some previous studies have shown that administration of contaminated enteral diets may produce nosocomial infections in critical patients. There is a series of factors in these patients which may enhance the risk of clinical complications deriving from the administration of enteral nutrition (EN) contaminated by microorganisms (alteration of the immunological state, increased stomach pH, reduced intestinal motility, reduced mucosa production, etc.). This study examines EN contamination in critical patients admitted to the ICU of the Hospital Universitario de Traumatología y Rehabilitación de las C. S. Vall d'Hebron, suffering from cranial-encephalic traumatism and/or multiple traumatism. The data made it possible to create a working design which takes account of factors which may increase the risk of EN contamination. The work was done in three phases, involving different handling procedures (Phase 1, Phase 2 and Phase 3). The results of the three studies made it possible to describe a working method in which the following points are outstanding: handwashing with antiseptic soap prior to handling the EN, avoidance of reuse of containers (if necessary) for more than 24 hours, not to exceed 8 hours' perfusion of EN previously handled, and not to wash the container prior to adding new quantities of EN.

Asepsis↗
PubMed1977

[Sources of microbial contamination in the production of veal].

Investigated was the microflora of various objects contributing to the contamination of veal during the process of its production. It was found that the main sources of primary contamination of the carcass surface with microorganisms are the hair coat, residual mud on the hoofs, intestinal contents of the calves for slaughter, the slaughter premise itself (walls, floor, air), tools used in slaughter (knives, axes for cutting open), clothing for work as well as the hands of the workers. The microbial contamination of the objects studied during work proved strong, in some cases the log value of the total count of organisms for some of them reaching up to 8.90, of the psychrophiles--up to 7.91, of the coliform bacteria--up to 7.04, of the moulds and yeasts--up to 6.08. Disinfection with 1 per cent water solution of Vosfasteril lowered the contamination of the objects studied by more than 99 per cent. The detergent used produced a high bactericidal effect and could successfully be employed at the meat producing enterprises throughout the country.

Animals↗
PubMed1985

Effects of sodium diacetate on the growth, feed efficiency, and intestinal microflora of broilers.

Three levels of sodium diacetate (.625, 1.25, and 3.75 g/kg diet) were incorporated into the diets of day-old broiler chicks. A control ration and a 20 mg/kg aureomycin ration were fed to additional groups of chicks. Each treatment contained 40 chickens at 3 weeks; the number was reduced to 20 chickens at 5 and 8 weeks. At 3 and 8 weeks of age, the large and small intestines of 5 chickens from each treatment were examined for selected microorganisms. Chick growth and feed efficiency were also recorded. The entire experiment was run twice, but in Trial 2 the lowest level of sodium diacetate treatment was replaced by a combination of sodium diacetate (.625 g/kg diet) and aureomycin (20 mg/kg diet). No improvement in the rate of growth was found in the sodium diacetate-treated groups, although additional weight gain was detected in aureomycin-fed groups at 2 weeks of age. Improved feed efficiency in the treated groups (sodium diacetate and aureomycin) was observed in both trials at 2 weeks and at 3 weeks of age in Trial 1. No feed efficiency effects were observed after that time. The sodium diacetate-fed groups showed an increased lactobacilli population in the small intestine along with a concurrent decrease in streptococci. The effect of sodium diacetate in reducing total coliforms in the large intestine was more obvious at 3 weeks than at 8 weeks. Aureomycin appeared to suppress the population of lactobacilli and total coliforms in this study. A combination of sodium diacetate and aureomycin failed to exhibit a synergistic effect either on the growth rate or on the intestinal microflora.

Acetates↗
PubMed2000

The role of probiotic cultures in the control of gastrointestinal health.

The use of probiotics to enhance intestinal health has been proposed for many years. Probiotics are traditionally defined as viable microorganisms that have a beneficial effect in the prevention and treatment of specific pathologic conditions when they are ingested. There is a relatively large volume of literature that supports the use of probiotics to prevent or treat intestinal disorders. However, the scientific basis of probiotic use has been firmly established only recently, and sound clinical studies have begun to be published. Currently, the best-studied probiotics are the lactic acid bacteria, particularly Lactobacillus sp. and Bifidobacterium sp. However, other organisms used as probiotics in humans include Escherichia coli, Streptococcus sp., Enterococcus sp., Bacteroides sp., Bacillus sp., Propionibacterium sp. and various fungi. Some probiotic preparations contain mixtures of more than one bacterial strain. Probiotics have been examined for their effectiveness in the prevention and treatment of a diverse spectrum of gastrointestinal disorders such as antibiotic-associated diarrhea (including Clostridium difficile-associated intestinal disease), infectious bacterial and viral diarrhea (including diarrhea caused by rotavirus, Shigella, Salmonella, enterotoxigenic E. coli, Vibrio cholerae and human immunodeficiency virus/acquired immunodeficiency disorder, enteral feeding diarrhea, Helicobacter pylori gastroenteritis, sucrase maltase deficiency, inflammatory bowel disease, irritable bowel syndrome, small bowel bacterial overgrowth and lactose intolerance. Probiotics have been found to inhibit intestinal bacterial enzymes involved in the synthesis of colonic carcinogens. There are many mechanisms by which probiotics enhance intestinal health, including stimulation of immunity, competition for limited nutrients, inhibition of epithelial and mucosal adherence, inhibition of epithelial invasion and production of antimicrobial substances. Probiotics represent an exciting prophylactic and therapeutic advance, although additional investigations must be undertaken before their role in intestinal health can be delineated clearly.

Clinical Trials as Topic↗
PubMed1994

An experimental model to reproduce some bacterial intestinal cocultures in germ-free mice.

The objective of this study was to create a stable experimental model to act as a living incubator for the main important intestinal bacteria. We have therefore inoculated germ-free mice with the most important bacteria of the human intestinal microflora, in order to study the effect of some oral antibiotics on the intestinal microflora. Sixty germ-free mice, 7 weeks old and of either sex, were inoculated orally with human faecal bacteria by means of their drinking water. Administrations were made at regular intervals following a scheme that respected some of the metabolic inter-relationships of the microorganisms used. The results showed that colonization of the germ-free mouse intestines had been achieved by most of the bacteria that had been inoculated. This "coculture" was stable in time, contrary to what happens when in-toto lyophilized faeces are administered, and the bacterial concentrations for each strains were similar to those found in human faeces.

Animals↗
PubMed2003

Intestinal metaplasia: evolution after Helicobacter pylori eradication and influence in the success of eradicating therapy.

INTRODUCTION: intestinal metaplasia associated with Helicobacter pylori infection is a stage of the temporal sequence of histological lesions gradually induced by this microorganism. It is considered a preneoplastic lesion and its regression after eradication is controversial. AIM: to assess the evolution of intestinal metaplasia after eradication and to investigate whether metaplasia is a factor that contributes to successful treatment. MATERIAL AND METHODS: four hundred Helicobacter pylori positive patients were studied. Eradicating therapy was administered and endoscopic biopsies of gastric antrum and body were taken before and after eradication. Among other histological data, the presence of intestinal metaplasia was assessed. RESULTS: of all patients successfully treated, biopsies were taken before and after eradication in 268 of them: 71 (26,5%) had metaplasia before and 50 (18,7%) after eradication. A significant difference was observed in the outcome (p = 0,036) of the first eradicating treatment between the group without initial metaplasia (72,7%) and the group with initial metaplasia (61.2%). DISCUSSION: Helicobacter pylori eradication can revert intestinal metaplasia in some patients. On the other hand, the first treatment could be less successful in patients with intestinal metaplasia.

Adult↗
PubMed1996

Neonatal gastrointestinal mucosal immunity.

The gastrointestinal mucosal immune system is a complex system with multiple interacting cells, which express different markers and elaborate a variety of mediators in response to noxious stimuli and pathogens. At birth this system is quite immature, putting the newborn mammal at risk for a variety of infectious and noninfectious diseases. With age and antigenic stimulation, maturation occurs and intestinal host defense then functions quite effectively to protect the host from ingested noxious substances and microorganisms.

Aging↗
PubMed2004

Microbial-gut interactions in health and disease. Epithelial cell responses.

Intestinal epithelial cells are unique in that they represent the only host cells that are constantly interacting with a very large bacterial population in the lumen. The single monolayer of epithelial cells consists of subpopulations with distinct functions that include protection against luminal microorganisms. Although the microbial flora remains to be fully characterized, its normal relationship with the host intestinal epithelial cells appears to be predominantly symbiotic or commensal. The molecular complexity of the epithelial-microbial relationship has been shown in studies that have examined the establishment of the resident bacteria in germ-free mice. Recent work has also demonstrated the ability of resident bacteria to enhance epithelial protective responses. The mechanisms by which epithelial cells may avoid pro-inflammatory responses to resident microorganisms, while retaining the capacity to respond to pathogens, are also being characterized.

Enterobacteriaceae↗
PubMed2003

The intestine and its microflora are partners for the protection of the host: report on the Danone Symposium "The Intelligent Intestine," held in Paris, June 14, 2002.

The intestine is an extremely complex living system that participates in the protection of the host through a strong defense against aggressions from the external environment. This defensive task is based on 3 constituents that are in permanent contact and dialog with each other: the microflora, mucosal barrier, and local immune system. We review herein current knowledge about these important functions. The gut microflora play a major role against exogenous bacteria through colonization resistance, but the mechanism of action is not yet established, although it is linked to the bacteria colonizing the gut. This colonization involves bacteria-bacteria dialog, bacteria-mucins interactions, and bacteria-colonocytes cross-talk associated with environmental factors. The intestinal mucosa is a cellular barrier and the main site of interaction with foreign substances and exogenous microorganisms. It is a complex physicochemical structure consisting of a mucous layer linked to cellular and stromal components that participate in the defense of the host through mucosal blood flow, mucosal secretions, epithelial cell functionals, surface hydrophobicity, and defensin production. The intestine is the primary immune organ of the body represented by the gut-associated lymphoid tissue through innate and acquired immunity. This immune system can tolerate dietary antigens and the gut-colonizing bacteria and recognizes and rejects enteropathogenic microorganisms that may challenge the body's defenses. In cooperation with these endogenous barriers, some in-transit bacteria, such as probiotics, can act as partners of the defense system of the intestine.

Adult↗
PubMed1999

A computer-controlled system to simulate conditions of the large intestine with peristaltic mixing, water absorption and absorption of fermentation products.

This paper introduces a new type of system to simulate conditions in the large intestine. This system combines removal of metabolites and water with peristaltic mixing to obtain and handle physiological concentrations of microorganisms, dry matter and microbial metabolites. The system has been designed to be complementary to the dynamic multi-compartmental system that simulates conditions in the stomach and small intestine described by Minekus et al. [Minekus M, Marteau P, Havenaar R, Huis in't Veld JHJ (1995) ATLA 23:197-209]. High densities of microorganisms, comparable to those found in the colon in vivo, were achieved by absorption of water and dialysis of metabolites through hollow-fibre membranes inside the reactor compartments. The dense chyme was mixed and transported by peristaltic movements. The potential of the system as a tool to study fermentation was demonstrated in experiments with pectin, fructo-oligosaccharide, lactulose and lactitol as substrates. Parameters such as total acid production and short-chain fatty acid (SCFA) patterns were determined with time to characterize the fermentation. The stability of the microflora in the system was tested after inoculation with fresh fecal samples and after inoculation with a microflora that was maintained in a fermenter. Both approaches resulted in total anaerobic bacterial counts higher than 10(10) colony-forming units/ml with physiological levels of Bifidobacterium, Lactobacillus, Enterobacteriaceae and Clostridium. The dry matter content was approximately 10%, while the total SCFA concentration was maintained at physiological concentrations with similar molar ratios for acetic acid, propionic acid and butyric acid as measured in vivo.

Absorption↗