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PubMed1990

Molecular definition of the bovine granulocytopathy syndrome: identification of deficiency of the Mac-1 (CD11b/CD18) glycoprotein.

Leukocytosis (34,600 WBC/microliter of blood) was detected in an apparently healthy 7-day-old Holstein heifer. Analysis of blood samples obtained over the next 41 days revealed chronic progressive neutrophilia, which peaked at greater than 85% neutrophils and exceeded 100,000 WBC/microliter. In vitro assessment of isolated blood neutrophils obtained from the heifer at 38 and 45 days of age revealed selected functional abnormalities. Endocytosis of immunoglobulin-opsonized Staphylococcus aureus and killing of this test organism by the calf's neutrophils were significantly diminished, as were phagocytosis-associated superoxide generation, chemiluminescence activity, and myeloperoxidase-catalyzed iodination. Diminished H2O2 elaboration by the calf's neutrophils was evident during ingestion of opsonized zymosan or on exposure to phorbol myristate acetate. Extracellular release (secretion) of elastase during ingestion of zymosan was also diminished, although total cell content of elastase was normal, compared with that of neutrophils from age-matched calves, and granular or other morphologic abnormalities of the calf's neutrophils were not evident by ultrastructural examination. Abnormalities of random migration were inconsistently detected, and normal or high degree of antibody-dependent cytotoxicity or natural killing by the calf's neutrophils was observed. Similar in vitro assessment of neutrophils obtained from the calf's dam revealed no functional abnormalities. The calf died at 48 days of age, with persistent fever and chronic diarrhea, despite administration of antibiotics. Histologic examination at necropsy revealed large numbers of intravascular neutrophils in most tissues, including massive neutrophil sequestration in spleen. However, a striking lack of extravascular neutrophils was evident in inflamed submucosa adjacent to intestinal ulcers heavily contaminated with enteric microorganisms. Bone marrow examination revealed diffuse myeloid hyperplasia, but no other abnormalities.

Animals↗
PubMedDate not supplied

[Sensitivity of opportunistic-pathogenic microflora isolated from humans to antibiotics before and after a stay in a hermetically closed chamber].

Antibiotic sensitivity of opportunistic microflora of men before and after exposure to an enclosed environment for as long as 2-8 to 96-175 days was investigated. It was found that after exposure the spectrum of opportunistic enterobacteria resistant to antibacterial drugs was enlarged. The results of serotyping of the isolated bacteria showed that one of the pathways that led to an increase in the number of antibiotic-resistant microorganisms was individual variations in the intestinal automicroflora which were characterized by a decrease in the amount of some species of enterobacteria and an increase in the amount of other species.

Anti-Bacterial Agents↗
PubMed1996

Streptococcus bovis spontaneous bacterial peritonitis in patients with alcoholic cirrhosis.

Spontaneous bacterial peritonitis (SBP) is a frequent cause of decompensated alcoholic cirrhosis. The authors describe the first two cases caused by infection with Streptococcus bovis. They suggest that this microorganism may be present in the intestinal flora of these patients more frequently than assumed. Furthermore, the course of SBP due to S. bovis may be particularly severe.

Fatal Outcome↗
PubMed1992

A review of recent advances in understanding ochratoxicosis.

Ochratoxin A (OA) is a toxin that contains an isocoumarin moiety linked by a peptide bond to phenylalanine. It is produced by certain Penicillium (mainly P. verrucosum) and Aspergillus (mainly A. alutaceus) species of storage fungi. Total amounts of OA and other related toxins produced by these fungi are influenced by many factors. Several forms of OA have been discovered, some of which are highly toxic, whereas others have lower toxicity. Ochratoxin A has been detected in foods, feeds, animal tissues, and human blood in both Europe and North America. It has been implicated in the fatal human disease Balkan endemic nephropathy, has been shown to be a powerful carcinogen in rodents, and produces many other adverse effects in animals. It is absorbed passively throughout the gastrointestinal tract and in an active manner in the kidney. It is subjected to intestinal secretion and reabsorption via enterohepatic recycling. Binding of OA in the blood to the albumin fraction and recycling in the bile and kidney contributes to its long half-life in animals. Ochratoxin A is hydrolyzed to its nontoxic alpha form (O alpha) by microorganisms in the rumen, cecum, and large intestine. The toxin is excreted primarily in the urine as O alpha and to a lesser degree as OA; smaller amounts of OA and O alpha are generally excreted in the feces. Three distinct mechanisms of OA toxicity have been proposed; other toxic effects of OA seem to be secondary in nature. Several different strategies can be employed for controlling or neutralizing the effect of OA, including the use of proper storage conditions, the use of specific adsorbents to reduce absorption of OA, and the feeding OA-contaminated feedstuffs to ruminants. Antioxidants such as ascorbic acid have been shown to reduce the toxic effects of OA in laying hens. In summary, OA contamination of cereal food and feed may occur, given appropriate conditions. Implementation of suitable procedures may eliminate or minimize this potentially serious problem.

Animals↗
PubMed1999

Functionality of probiotics and intestinal lactobacilli: light in the intestinal tract tunnel.

The commercial interest in functional foods that contain live microorganisms, also termed probiotics, is paralleled by increasing scientific attention to their functionality in the digestive tract. Most studies are focused on intestinal Lactobacillus species, which are part of the natural gastro-intestinal microbiota, and include analysis of colonisation factors and other interactions with the host, the design of novel or improved strains with specific health benefits, and the application of sophisticated molecular tools to determine their fate and activity in situ.

Genetic Techniques↗
PubMed2006

[Inflammatory bowel diseases: in search of novel cytokines and genes].

Inflammatory bowel diseases are chronic idiopathic intestinal disorders that have diverse manifestations such as diarrhea, rectal bleeding, abdominal pain, weight loss, fever and extraintestinal manifestations. The current concept regarding their immunopathogenesis is that, in a genetically susceptible host, an aberrant response of the mucosa associated lymphoid tissue (MALT) towards a non-pathogenic microorganism, elicits the cascade that culminates in intestinal inflammation. In this issue of HAREFUAH, Waterman M & al have screened IBD vs. control population in search of a genetic association between IBD and the interleukin 13 polymorphism 2044+G/A, on chromosome 5. Although they have found no such association, the editorial addresses the importance of cytokines and novel genes for the understanding of the immunopathogenesis of inflammatory bowel diseases, and its treatment.

Cytokines↗
PubMed2003

Lactobacillus acidophilus, Bifidobacterium lactis and Lactobacillus F19 prevent antibiotic-associated ecological disturbances of Bacteroides fragilis in the intestine.

OBJECTIVE: The objective of this study was to compare the effect of clindamycin on the intestinal microflora in subjects ingesting yogurt with added probiotic microorganisms with the microflora in subjects ingesting placebo yogurt. MATERIALS AND METHODS: Twenty-four healthy subjects were included in the study. All subjects received 150 mg clindamycin four times daily for 7 days and 250 ml yogurt twice daily for 14 days. Faecal samples were collected before, during and after administration of clindamycin. RESULTS: In the aerobic intestinal microflora, the numbers of enterococci increased after treatment in both groups, whereas other Gram-positive microorganisms decreased. In both groups, the numbers of Escherichia coli also decreased, whereas there was a concomitant increase in numbers of other Gram-negative bacilli. In the anaerobic microflora in subjects receiving yogurt with added microorganisms, the numbers of lactobacilli and bacteroides remained at the same levels throughout the study, whereas the numbers decreased in the placebo group. Other anaerobic bacteria decreased in both groups. The minimum inhibitory concentration of clindamycin against strains of bacteroides increased in both groups during the study. CONCLUSIONS: The probiotic microorganisms evaluated in this study prevented ecological disturbances in the numbers of intestinal Bacteroides fragilis group species during clindamycin administration.

Adult↗
PubMed1970

Unusual Sphaerophorus species from the large intestine of man.

An obligately anaerobic, gram-negative microorganism identified as a Sphaerophorus species was recovered from the fecal material of two cancer (chronic myelogenous leukemia and idiopathic thrombocythemia) patients receiving cobalt radiation therapy. The organism, isolated on sheep blood-agar, exhibited extreme pleomorphism (rods, filaments, and spheroids) and was a major component of the anaerobic fecal microflora. In one patient the numbers of Sphaerophorus species (designated as isolate 6-13-68), Bacteroides species, and Clostridium perfringens declined after irradiation; however, they were stable in this same patient after a second therapeutic dose of radiation. The numbers of anaerobes in the other patient remained fairly consistent after radiation. The biochemical and morphological characteristics and carbohydrate fermentation reactions of isolate 6-13-68 most closely resembled those of Sphaerophorus ridiculosis.

Agar↗
PubMed2000

Comparison of the effects of hospitalization and antibiotic usage on the aerobic intestinal flora.

Antimicrobial resistance among bacteria has arisen ever since antimicrobial agents were introduced in the clinic. Unfortunately, it seems that resistance is now emerging at a more rapid rate than ever before, as a consequence of the widespread use of antimicrobial agents. The spread of these multiresistant microorganisms is an increasing threat in many countries. The human intestinal flora is a huge potential reservoir of resistant microorganisms. Antimicrobial resistance in clinical isolates may cause serious infections and treatment failure, and lead to the use of higher doses or more toxic alternative drugs. This study was planned so as to compare the effects of hospitalization and antibiotic usage on the aerobic intestinal flora and included 43 hospitalized adult patients without any previous history of hospitalization and antibiotic usage during the last 30 d. Patients were divided according to their antimicrobial therapy, into treated and untreated groups. The individual use of antimicrobials was recorded. Antibiotic usage was found to be more effective on the aerobic intestinal flora compared with hospitalization without such medication.

Adolescent↗
PubMed2003

Characterization of Vibrio fluvialis-like strains implicated in limp lobster disease.

Studies were undertaken to characterize and determine the pathogenic mechanisms involved in a newly described systemic disease in Homarus americanus (American lobster) caused by a Vibrio fluvialis-like microorganism. Nineteen isolates were obtained from eight of nine lobsters sampled. Biochemically, the isolates resembled V. fluvialis, and the isolates grew optimally at 20 degrees C; none could grow at temperatures above 23 degrees C. The type strain (1AMA) displayed a thermal reduction time (D value) of 5.77 min at 37 degrees C. All of the isolates required at least 1% NaCl for growth. Collectively, the data suggest that these isolates may embody a new biotype. Pulsed-field gel electrophoresis (PFGE) analysis of the isolates revealed five closely related subgroups. Some isolates produced a sheep hemagglutinin that was neither an outer membrane protein nor a metalloprotease. Several isolates possessed capsules. The isolates were highly susceptible to a variety of antibiotics tested. However, six isolates were resistant to erythromycin. Seventeen isolates harbored plasmids. Lobster challenge studies revealed that the 50% lethal dose of a plasmid-positive strain was 100-fold lower than that of a plasmid-negative strain, suggesting that the plasmid may enhance the pathogenicity of these microorganisms in lobsters. Microorganisms that were recovered from experimentally infected lobsters exhibited biochemical and PFGE profiles that were indistinguishable from those of the challenge strain. Tissue affinity studies demonstrated that the challenge microorganisms accumulated in heart and midgut tissues as well as in the hemolymph. Culture supernatants and polymyxin B lysates of the strains caused elongation of CHO cells in tissue culture, suggesting the presence of a hitherto unknown enterotoxin. Both plasmid-positive and plasmid-negative strains caused significant dose-related intestinal fluid accumulations in suckling mice. Absence of viable organisms in the intestinal contents of mice suggests that these microorganisms cause diarrhea in mice by intoxication rather than by an infectious process. Further, these results support the thermal reduction data at 37 degrees C and suggest that the mechanism(s) that led to fluid accumulation in mice differs from the disease process observed in lobsters by requiring neither the persistence of viable microorganisms nor the presence of plasmids. In summary, results of lobster studies satisfy Koch's postulates at the organismal and molecular levels; the findings support the hypothesis that these V. fluvialis-like organisms were responsible for the originally described systemic disease, which is now called limp lobster disease.

Animals↗
PubMed1992

2,4,5-trichlorophenoxyacetic acid influence on 2,6-dinitrotoluene-induced urine genotoxicity in Fischer 344 rats: effect on gastrointestinal microflora and enzyme activity.

2,4,5-Trichlorophenoxyacetic acid (2,4,5-T) and 2,6-dinitrotoluene (2,6-DNT) are hazardous chemicals that have potential harmful effects. 2,6-DNT is recognized as a hepatotoxicant while 2,4,5-T, a component of Agent Orange, is also suspect. 2,6-DNT requires both oxidative and reductive metabolism to elicit genotoxic effects. To determine what effect 2,4,5-T had on 2,6-DNT metabolism, intestinal enzymes, microbial populations, and urine mutagenicity were examined during 2,4,5-T treatment. Weanling Fischer 344 male rats were treated daily with 54.4 mg/kg 2,4,5-T by gavage for 4 weeks. One, two, and four weeks after the initial 2,4,5-T dose, rats were administered (po) 2,6-DNT (75 mg/kg) and urine was collected for 24 hr in metabolism cages. Azo reductase, nitroreductase, beta-glucuronidase, dechlorinase, and dehydrochlorinase activities were examined concurrently. Treatment of rats for 1 week reduced the transformation of 2,6-DNT to mutagenic urinary metabolites. This was accompanied by a decrease in the fecal anaerobic microorganisms. The elimination of Lactobacillus fermentum from the small intestine and cecum of treated animals accompanied a significant increase in oxygen-tolerant lactobacilli and other unidentified aerobic microorganisms. However, there were no significant alterations in the intestinal enzyme activities examined. By 2 weeks of 2,4,5-T treatment, microbiota and urine genotoxicity returned to the levels observed in control animals. This trend continued for the duration of the experiment. After 2 weeks, while cecal nitroreductase and azo reductase activities increased, small intestinal beta-glucuronidase activity decreased. By 4 weeks, treated and untreated animal intestinal enzyme activities were indistinguishable.(ABSTRACT TRUNCATED AT 250 WORDS)

2,4,5-Trichlorophenoxyacetic Acid↗
PubMed2001

Extensive surface diversity of a commensal microorganism by multiple DNA inversions.

The dynamic interactions between a host and its intestinal microflora that lead to commensalism are unclear. Bacteria that colonize the intestinal tract do so despite the development of a specific immune response by the host. The mechanisms used by commensal organisms to circumvent this immune response have yet to be established. Here we demonstrate that the human colonic microorganism, Bacteroides fragilis, is able to modulate its surface antigenicity by producing at least eight distinct capsular polysaccharides-a number greater than any previously reported for a bacterium-and is able to regulate their expression in an on-off manner by the reversible inversion of DNA segments containing the promoters for their expression. This means of generating surface diversity allows the organism to exhibit a wide array of distinct surface polysaccharide combinations, and may have broad implications for how the predominant human colonic microorganisms, the Bacteroides species, maintain an ecological niche in the intestinal tract.

Antigenic Variation↗
PubMed2006

[Current situation of the study on treatment of bacteria translocation with integrated traditional Chinese and Western medicine].

Bacteria translocation (BT) induced enterogenous infection in multiple organs dysfunction syndrome (MODS) is closely related with the stress pyemia and MODS. For prevention of BT, western medicine stresses to improve the blood and oxygen supply of intestinal tract, mucosa protection, and application of microorganism preparation, while traditional Chinese medicine could also win good effect by using such drugs as rhubarb, red sage root, and compound decoctions.

Animals↗
PubMedDate not supplied

[The symbiotic microflora associated with the tegument of proteocephalidean cestodes and the intestines of their fish hosts].

The indigenous symbiotic microflora associated with the tegument of proteocephalidean cestodes and the intestines of their fish hosts has been investigated in morphological and ecological aspects. The indigenous microflora associated with the cestode tegument consists of the nannobacteria population, which was present obligatorily on the surface of tegument, and the "deep microflora". The deep microflora associates with some few species of parasites only. Each individual host-parasite micro-biocenosis includes specific indigenous symbiotic microorganisms, with the differing microfloras of host intestine and parasite. Physiology, biochemistry and/or diet of hosts apparently influence on the symbiotic microflora's structure of parasites. The least bacteria abundance and diversity of their morphotypes were observed in the parasites from baby fishes. The diversity and abundance of bacteria were increased with the fish host ageing and the formation of the definitive structure of its intestine. It is an evidence of the gradual invading of the intestinal parasites (cestodes) tegument by bacterial cells. The invading is realized on the base of the microflora that was present in the food of fish host. The symbiotic microflora has specific morphological features, can regulate the homeostasis of the cestodes and fish hosts and also can maintain equilibrium of alimentary and immune interrelations in the host-parasite system.

Animals↗
PubMed1955

Studies on susceptibility to infection following ionizing radiation. IV. The pathogenesis of the endogenous bacteremias in mice.

In half of the normal mice examined, cultures of mesenteric lymph nodes were positive for enteric bacteria. When a non-pathogenic microorganism, Serratia marcescens, was established in the intestinal tract by administering it to mice in their drinking water, it, too, was recovered from the mesenteric lymph nodes of almost half of the normal mice examined. From these findings it was concluded that bacteria in small numbers were able to pass from the lumen of the unirradiated gut as far as the regional lymph glands. Such bacteria, except the pathogen, Salmonella, were rarely found in liver or spleen, never in the blood of the normal mice. After x-irradiation with 700 r, the incidence of positive cultures showed the liver or spleen became infected with enteric microorganisms before the blood stream was invaded. It appears, therefore, that these elements of the reticulo-endothelial system were able for a time to maintain the sterility of the blood after failure of the more immediate defenses against bacterial invasion from the intestinal tract. It is concluded that if any increased migration of bacteria through the intestinal mucosa resulted from the radiation injury, the increase must have occurred very soon after irradiation.

Animals↗
PubMed1992

Pathways of lymph flow through intestinal lymph nodes in the horse.

In the horse, several thousand lymph nodes receive lymph from the intestine, part of which is very large and contains microorganisms that enable the animal to utilize refractory dietary constituents such as cellulose. The aim of this study was to describe the pathways by which lymph is delivered into, traverses, and is drained from these lymph nodes. These pathways were studied with either Microfil or methacrylate casting materials and with light and electron microscopy. The afferent lymphatic vessel delivering lymph into one of the nodes divides over the capsular surface and within trabeculae into terminal branches, and these are continuous with the subcapsular and trabecular sinuses through rounded holes up to 30 microns across. Lymph is conveyed from the subcapsular and trabecular sinuses through the cortex by four types of sinuses: trabecular sinuses, cortical tubular sinuses, tubule-like sinuses with a network of stellate cell processes, and sinuses between cortical cords. It is conveyed through the medulla by sinuses both within and between medullary cords. Lymph is drained from these sinuses by initial efferent lymphatics of three types: those between medullary cords, those within the subcapsular sinus overlying medullary or cortical cords, and those within trabeculae. All three types are continuous with surrounding sinuses through holes 5-30 microns across. These three alternative routes for lymph drainage may ensure adequate lymph flow during different intranodal conditions that may exist when the node is responding to microorganisms or other foreign materials.

Animals↗
PubMed2003

Expression and regulation of antimicrobial peptides in the gastrointestinal tract.

The gastrointestinal (GI) tract is exposed to a wide range of microorganisms. The expression of antimicrobial peptides has been demonstrated in different regions of the GI tract, predominantly in epithelial cells, which represent the first host cells with which the microorganisms have to interact for invasion. The intestinal epithelial monolayer is complex, consisting of different cell types, and most have a limited lifespan. Of the GI antimicrobial peptides, alpha- and beta-defensins have been studied the most and are expressed by distinct types of epithelial cells. Enteric alpha-defensin expression is normally restricted to Paneth and intermediate cells in the small intestine. However, there are important differences between mice and humans in the processing of the precursor forms of enteric alpha-defensins. Parasite infection induces an increase in the number of enteric alpha-defensin-expressing Paneth and intermediate cells in the murine small intestine. In the chronically inflamed colonic mucosa, metaplastic Paneth cells (which are absent in the normal colon) also express enteric alpha-defensins. Epithelial expression of beta-defensins may be constitutive or inducible by infectious and inflammatory stimuli. The production of some members of the beta-defensin family appears to be restricted to distinct parts of the GI tract. Recent studies using genetically manipulated rodents have demonstrated the likely in vivo importance of enteric antimicrobial peptides in innate host defense against microorganisms. The ability of these peptides to act as chemoattractants for cells of the innate- and adaptive-immune system may also play an important role in perpetuating chronic inflammation in the GI tract.

Amino Acid Sequence↗