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PubMed1990

[The etiological structure of acute intestinal infections].

The share of various etiologic forms of acute intestinal infections, diagnosed by bacteriologic methods, is presented. The share of gastroenterocolitis induced by opportunistic microflora makes up 35.6%, that of dysentery 25.6%, salmonellosis 18.5%; mixed infection (dysentery + salmonellosis) is diagnosed in 7% of cases with acute intestinal infections. The principal representative of opportunistic microflora isolated from patients with acute intestinal infections is the Klebsiella genus (40.6%), whereas in the reference group Citrobacter, Morganella, and Klebsiella detection rates are approximately the same (27.0-18.3%). Opportunistic microorganisms in titers under 10(6) are isolated from normal subjects 5 times more frequently than from the patients, this indicating the diagnostic value of this level of feces contamination with opportunistic microflora.

Acute Disease↗
PubMedDate not supplied

[Antilactoferrin activity of microorganisms].

The detection rate of the antilactoferrin sign and the level of its manifestation in 165 strains of different microbial species, isolated from patients with inflammatory diseases and intestinal dysbacteriosis, were analyzed. The detection rate of antilactoferrin activity was 43 - 90% for Escherichia coli strains, 20 - 86% for Staphylococcus aureus, 60 - 100% for Klebsiella pneumoniae, 76 - 78% for Candida albicans, isolated from different biotopes of man. Most frequently and with high levels of manifestation this sign was registered in strains isolated from the reproductive tract of women. The detection rate of this sign and the level of its manifestation in bacteria of the vaginal and cervical microbiocenosis, isolated from patients, were higher in comparison with healthy persons. The inverse dependence between the level of the antilactoferrin activity of microflora and the content of lactoferrin during the inflammatory process in women was established.

Biological Factors↗
PubMed2000

Identification of genes involved in mucosal defense and inflammation associated with normal enteric bacteria.

Normal luminal bacteria and their products play a role in experimental colitis and inflammatory bowel disease. However, what molecules from what cells are responsible for mounting and maintaining the mucosal defense against luminal flora is still uncertain. The aim of this study was to identify epithelial gene products involved in mucosal defense and inflammation associated with ubiquitous enteric bacteria. Germ-free ICR mice were given an oral bacterial suspension prepared from conventional components (bacterial reconstitution). Small intestinal and colonic epithelial cells were isolated from bacteria-reconstituted, germ-free, and specific pathogen-free mice. Differential gene expression was investigated by differential display, Northern blot, and sequence analysis. Bacterial reconstitution resulted in acute but self-limited colitis. In epithelial cells, we observed the induction of small intestine-specific genes of the cryptdin family and colon-specific expression of serum amyloid A1 gene. This novel approach allows the identification of known and novel gene products involved in mucosal defense against luminal microorganisms and the associated inflammatory response.

Animals↗
PubMed1990

Apparition of Clostridium sp. and Bacteroides in the intestine of the newborn delivered by cesarian section.

Anaerobic flora plays a key role in preventing intestinal colonization with potential pathogens. Nowadays, the mechanisms involved in the colonization resistance provided by the anaerobic microflora are to be clarified. Numerous factors seem to intervene in the regulation of the intestinal flora. The purpose of the present study was to correlate the presence or relative absence of Clostridium sp. and Bacteroides with the colonization by C. perfringens, which is involved in lethal infections in an immunologically compromised host. The intestinal bacterial colonization of 20 newborns delivered by cesarian section was assessed sequentially over the first 14 days of life. C. perifringens is a strongly reducing microorganism and undoubtedly causes a decrease in the oxidoreduction potential of the newborn feces favouring the subsequent colonization by other putrefactive bacteria. C. perfringens seems to be the precursor for installation of putrefractive bacteria, as Bacteroides and other Clostridium sp.

Anaerobiosis↗
PubMed1996

Phylogenetic diversity of the intestinal bacterial community in the termite Reticulitermes speratus.

The phylogenetic diversity of the intestinal microflora of a lower termite, Reticulitermes speratus, was examined by a strategy which does not rely on cultivation of the resident microorganisms. Small-subunit rRNA genes (16S rDNAs) were directly amplified from the mixed-population DNA of the termite gut by the PCR and were clonally isolated. Analysis of partial 16S rDNA sequences showed the existence of well-characterized genera as well as the presence of bacterial species for which no 16S rDNA sequence data are available. Of 55 clones sequenced, 45 were phylogenetically affiliated with four of the major groups of the domain Bacteria: the Proteobacteria, the spirochete group, the Bacteroides group, and the low-G+C-content gram-positive bacteria. Within the Proteobacteria, the 16S rDNA clones showed a close relationship to those of cultivated species of enteric bacteria and sulfate-reducing bacteria, while the 16S rDNA clones in the remaining three groups showed only distant relationships to those of known organisms in these groups. Of the remaining 10 clones, among which 8 clones formed a cluster, there was only very low sequence similarity to known 16S rRNA sequences. None of these clones were affiliated with any of the major groups within the domain Bacteria. The 16S rDNA gene sequence data show that the majority of the intestinal microflora of R. speratus consists of new, uncultured species previously unknown to microbiologists.

Animals↗
PubMed2000

Bacterial interplay at intestinal mucosal surfaces: implications for vaccine development.

The discovery of 'molecular syringes' in several important gastrointestinal pathogens including Escherichia coli, Salmonella, Shigella and Yersinia, together with a better understanding of M cells and the mucosal immune system, has advanced our appreciation of multistage microorganism-host cell interactions. Recent studies suggest that these molecular strategies could be adapted for the development of modular mucosal vaccines.

Bacterial Proteins↗
PubMed1989

[The role of swimming pools in the spread of intestinal infections].

A kindergarten swimming bath was experimentally infested with M-17 Bacillus coli. It was found that after bathing 10% of children showed Escherichia M-17 in the feces. It is concluded that presence of conditionally pathogenic microorganisms in the water of swimming baths may be considered a qualitative and quantitative criterion of epidemic risk during bathing in infected basins in case hygienic norms are not observed per person.

Child↗
PubMed1996

M cells in Peyer's patches of the intestine.

M cells are specialized epithelial cells of the mucosa-associated lymphoid tissues. A characteristic of M cells is that they transport antigens from the lumen to cells of the immune system, thereby initiating an immune response or tolerance. Soluble macromolecules, small particles, and also entire microorganisms are transported by M cells. The interactions of these substances with the M cell surface, their transcytosis, and the role of associated lymphoid cells are reviewed in detail. The ultrastructure and several immuno- and lectin-histochemical properties of M cells vary according to species and location along the intestine. We present updated reports on these variations, on identification markers, and on the origin and differentiation of M cells. The immunological significance of M cells and their functional relationship to lymphocytes and antigenpresenting cells are critically reviewed. The current knowledge on M cells in mucosa-associated lymphoid tissues outside the gut is briefly outlined. Clinical implications for drug deliver, infection, and vaccine development are discussed.

Animals↗
PubMedDate not supplied

[Bacterial ecology of the digestive tract and defense of the body].

The indigenous microflora of the upper digestive tract is poorly developed and consists of microorganisms in transit, originating in the oro-pharynx. Aerobic bacteria, mainly streptococci, predominate. In the normohydrochloric stomach, the mean fasting bacterial concentration is 10(3)-10(4)/ml gastric juice. In the small intestine, levels of up to 10(5) bacteria/ml contents are reached. The essential mechanism which maintains this relative sterility of the upper digestive tract is the gastro-intestinal transit and in particular the interdigestive migrating motor complex. In the terminal ileum, a zone subject to relative stasis, the intraluminal bacterial population rises to 10(8)/ml in one third of subjects, with the appearance of enterobacter and strict anaerobes. In the colon, a zone of physiological stasis, the number of microorganisms per ml of contents is 10(8)-10(9) on the right side and 10(10)-10(12) on the left side. The dominant flora is strictly anaerobic and the subdominant flora optionally aero-anaerobic, consist mainly of Enterobacter, Streptococci and Lactobacilli. The balance between the species of microorganisms in the colonic ecosystem and its stability results primarily from microbial antagonisms. The barrier flora, consisting of groups of anaerobes, either prevent the implantation of exogenous microorganisms (drastic barrier) or limit it to the subdominant flora (permissive barrier). The repression of the subdominant flora by the dominant flora prevents the subdominant flora from spreading to the mesenteric ganglia and then the whole body. Rupture of the barrier flora by a wide-spectrum antibiotic may permit the local multiplication of a pathogenic organism (C. difficile, Salmonella), or the spread of an opportunist organism (Klebsiella pneumoniae).

Animals↗
PubMed2005

Adhesion to sole, Solea senegalensis Kaup, mucus of microorganisms isolated from farmed fish, and their interaction with Photobacterium damselae subsp. piscicida.

Abstract Most studies carried out to select microorganisms as candidate probiotics have focused on in vitro antagonism tests, such as the production of inhibitory compounds against pathogenic microorganisms. However, attachment to mucous surfaces could be another criterion to be considered when selecting potential probiotics for aquaculture. Nineteen isolates obtained from farmed Senegalese sole, Solea senegalensis Kaup, and gilthead sea bream, Sparus aurata L., have been evaluated for their capacity to adhere to skin and intestinal mucus of Senegalese sole, and their antagonistic effect against Photobacterium damselae subsp. piscicida, an important pathogen for farmed sole. The isolates from gilthead sea bream showed the highest percentage of adhesion to sole mucus, whilst the pathogenic microorganisms assayed and the isolates from sole showed, in general, a lower ability to adhere to sole mucus. The results suggest that the adhesion to fish mucus was more dependent on the isolate tested than on the host mucus. The isolates from gilthead sea bream also showed a higher antagonistic activity against P. damselae subsp. piscicida than those from Senegalese sole. Four isolates were selected, on the basis of their adhesive ability and antagonistic effect on P. damselae subsp. piscicida, to study their interactions with the pathogen in respect of adhesion to skin and intestinal mucus under exclusion, competition and displacement conditions. The results obtained show the ability of three isolates to reduce the adhesion of P. damselae subsp. piscicida to sole mucus under displacement and competition conditions. The adhesion of the pathogen to sole intestinal mucus was also significantly reduced when three isolates were assayed under exclusion conditions.

Animals↗
PubMedDate not supplied

[Central nervous system mycotic infections].

INTRODUCTION: There has been an increased number of cases of fungal diseases of the central nervous system (CNS) during the past few years. This paper reviews current literature about these conditions, with emphasis on recent advances on diagnosis and therapy. DEVELOPMENT: While some fungi may cause disease in normal hosts, most of these microorganisms are opportunistics and affect immunocompromised hosts. With the exception of Candida albicans, that is a normal inhabitant of the intestinal tract, most fungi enter the body by inhalation or through skin abrasions. Common fungal diseases include aspergillosis, blastomycosis, candidiasis, coccidioidomycosis, cryptococcosis, histoplasmosis, mucormycosis, paracoccidioidomycosis, and phaeohyphomycosis. In general terms, fungal invasion of the CNS may produce one or more of the following clinical syndromes: subacute or chronic meningitis, encephalitis, parenchymal brain abscesses or granulomas, stroke, or myelopathy. Diagnosis may be difficult on clinical grounds, and data provided by neuroimaging studies or CSF examination is non-specific. Definitive diagnosis usually rest on the demonstration of the causal agent on body fluids or tissue samples. Early administration of amphotericin B, associated or not with the new azoles, is indicated to arrest the often fatal course of these conditions. CONCLUSIONS: Formerly considered rare diseases, the acquired immunodeficiency syndrome (AIDS) epidemic and the widespread use of corticosteroids and cytotoxic agents, have caused an increase in the prevalence of CNS mycosis. Development of potent antimycotic drugs have improved the prognosis of fungal diseases of the CNS. However, due to diagnostic delays or the presence of debilitating conditions, some patients still have torpid clinical courses despite proper therapy.

Central Nervous System Fungal Infections↗
PubMed2002

[Antibiotic induced diarrhea and pseudomembranous colitis].

The spore-forming anaerobic bacterium Clostridium difficile has become a serious enteropathogen. Oral and parenteral administration of antibiotics can cause ecological disturbances in the normal intestinal microflora. Suppression of the normal microflora may lead to reduced colonization resistance with subsequent overgrowth by pre-existing, naturally resistant microorganisms, such as C. difficile. C. difficile infection shows a range of clinical presentations between an asymptomatic carrier state, light diarrhea without inflammatory changes, and pseudomembranous colitis. C. difficile infection is acquired by the fecal-oral or environmental-oral routes. From March 2000 through March 2001 we assessed 48 cases of nosocomial antibiotic-associated diarrhea (AAD). Of these, 21 were due to C. difficile (CDAD). Cephalosporin was the agent most commonly associated with CDAD. Avoidance of cephalosporins, strict use of "single shot" prophylaxis, isolation of infected, symptomatic patients in single-bed rooms, improved hygiene and complete room disinfection lead to a rapid decrease of CDAD. The etiology, prognosis and prophylaxis are discussed in this paper.

Aged↗
PubMed1976

Microorganisms responsible for controlling the populations of Escherichia coli and enterococcus and the consistency of cecal contents in the chicken.

A study was made to clarify what kinds of intestinal organisms might be responsible for controlling the populations of Escherichia coli and Streptococcus faecalis var. liquefaciens in the cecum and the consistency of the cecal of chickens. Germ-free chickens were inoculated orally with various mixtures of bacterial cultures alone or in combination, different dilutions of the cecal contents of chickens, different dilutions of the cecal contents treated by healing or with chloroform, the supernatant of diluted cecal contents, and dilutions of human feces. Factors controlling the E. Coli populations, enterococcal populations, and consistency of the cecal contents were shown to be independent of one another. The ecosystem controlling the E. coli or enterscoccal population was more complex than that controlling the consistency of the cecal contents. The former was composed of anaerobic and facultatively anaerobic bacteria isolated and heat- or chloroform-resistance organisms, and the latter of heat- or chloroform-resistance alone, which were inferred not to prevailing in the cecal contents of chickens. Discussion is made on ecological systems controlling flora.

Animals↗
PubMed2004

Functional modulation of enterocytes by gram-positive and gram-negative microorganisms.

Clinical studies have suggested that so-called probiotic bacteria may be effective as therapy in inflammatory bowel disease. However, the molecular mechanisms of their interaction with the intestinal surface remain undefined. The influence of whole probiotic bacteria [Escherichia coli Nissle 1917 (EcN); probiotic mixture VSL#3 (PM)], bacterial cell lysates, and conditioned media on transepithelial resistance (TER), IL-8 secretion, mucin gene expression, and tight junction proteins were determined in T84 and HT-29 intestinal epithelial cells (IEC). In addition, effects on pathogen (Salmonella dublin)-induced alterations were analyzed. EcN as well as debris and cell extracts induced IL-8 secretion from IEC, whereas no such effect was observed following incubation with the PM. The PM and soluble protein(s) released from the PM increased TER, prevented pathogen-induced decrease in TER, and were shown to stabilize tight junctions. The PM induced expression of mucins in IEC, and these organisms as well as EcN diminished S. dublin-induced cell death. Inhibition of MAPKs with PD-98059 or SB-203580 significantly decreased alterations in IL-8 synthesis and mucin expression and affected the regulation of TER. Probiotics and protein(s) released by these organisms may functionally modulate the intestinal epithelium of the host by different mechanisms, including the competition of whole organisms for contact with the epithelial surface as well as stabilization of the cytoskeleton and barrier function and the induction of mucin expression. Gram-negative and gram-positive organisms differ in the mechanisms activated, and a combination of organisms might be more effective than the application of a single strain.

Blotting, Western↗
PubMed1991

[Ultrastructural changes in the intestinal mucosa of children with chronic diarrhea].

Observations were made on biopsied small bowel mucosa by scanning and transmission electron microscopy in 21 infants and children, with chronic diarrhea, their age ranging from 3 months to 24 months, 85.7% of the patients showed various degrees of malnutrition. Ultrastructural changes in the small intestinal mucosa occurred in all of the cases analyzed. The major findings were: (1) villous atrophy; (2) damage to enterocytes, presenting increased extrusion of cytoplasm and enterocytes, with damage of the microvillar surface and degenerative changes of cytoplasm; (3) presence of microorganisms on the mucosal surface; and (4) excessive mucus on the mucosal surface. These results suggest that prolonged mucosal injury, extensive colonization of the mucosal surface by microorganisms, and malnutrition, may be the main causes of chronic diarrhea in children.

Biopsy↗
PubMed1989

Role of intestinal microflora in the metabolism of vitamin B-6 and 4'-deoxypyridoxine examined using germfree guinea pigs and rats.

In previous work identification of urinary metabolites of 4'-deoxypyridoxine which had been oxidized in the 5'-position and long-term dilution of labeled urinary metabolites with unlabeled molecules suggested possible microbial contributions. In the current studies germfree guinea pigs were able to convert 4'-deoxypyridoxine to 4'-deoxy-5-pyridoxic acid demonstrating that the ability to oxidize the 5'-position is not restricted to microorganisms. Labelling curves for urinary pyridoxic acid in rats continuously fed [14C]pyridoxine since weaning were similar in conventional and germfree animals indicating that any vitamin B-6 synthesized in the intestinal tract was not readily absorbed and metabolized. Therefore, coprophagy did not make a detectable contribution to vitamin B-6 metabolism in rats receiving a nutritionally complete diet. The difficulty in achieving comparable labeling in adult animals is probably due to very slow turnover of portions of the vitamin B-6 pool and not to microbial production of vitamin B-6. The total pool calculated from the radioactivity in the germ-free rats averaged 16.2 +/- 0.8 nmol vitamin B-6 compounds/g body wt. Only 10% of the ingested label was recovered in the feces. In addition, only about 50% of the label excreted in the urine appeared as 4-pyridoxic acid in rats. These observations suggest that it may be difficult to quantitate the total urinary and fecal excretion of ingested vitamin B-6 without using tracers.

Animals↗