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At least 1,243 records · Page 69Linked to original sources
PubMed2003

Interaction between probiotic lactic acid bacteria and canine enteric pathogens: a risk factor for intestinal Enterococcus faecium colonization?

Selected probiotic lactic acid bacteria (LAB) have been shown to elicit positive health effects particularly in humans. Competitive exclusion of pathogens is one of the most important beneficial health claims of probiotic bacteria. The effect of probiotic LAB on competitive exclusion of pathogens has been demonstrated in humans, chicken and pigs. In this study we evaluated the ability of certain LAB strains (Lactobacillus rhamnosus GG, Bifidobacterium lactis Bb12, Lactobacillus pentosus UK1A, L. pentosus SK2A, Enterococcus faecium M74 and E. faecium SF273) to inhibit the adhesion of selected canine and zoonotic pathogens (Staphylococcus intermedius, Salmonella Typhimurium ATCC 14028, Clostridium perfringens and Campylobacter jejuni) to immobilised mucus isolated from canine jejunal chyme in vitro. Adhesion of C. perfringens was reduced significantly by all tested LAB strains, between 53.7 and 79.1% of the control without LAB, the LAB of canine origin yielding the best reduction. The adhesion of S. Typhimurium and S. intermedius were not significantly altered by any of the LAB included in the study. Both enterococci tested significantly enhanced the adhesion of C. jejuni, to 134.6 and 205.5% of the control without LAB. E. faecium may thus favor the adhesion and colonization of C. jejuni in the dog's intestine, making it a potential carrier and possibly a source for human infection. Enhanced C. jejuni adhesion is a new potential risk factor of enterococci. Our results further emphasize the importance of safety guidelines to be established for the probiotics intended for animal use.

Animals↗
PubMed2005

Cathelicidin mediates innate intestinal defense against colonization with epithelial adherent bacterial pathogens.

Cathelicidin-related antimicrobial peptide (mCRAMP), the sole murine cathelicidin, is encoded by the gene Cnlp. We show that mCRAMP expression in the intestinal tract is largely restricted to surface epithelial cells in the colon. Synthetic mCRAMP had antimicrobial activity against the murine enteric pathogen Citrobacter rodentium, which like the related clinically important human pathogens enteropathogenic Escherichia coli and enterohemorrhagic E. coli, adheres to the apical membrane of intestinal epithelial cells. Colon epithelial cell extracts from Cnlp+/+ mice had significantly greater antimicrobial activity against C. rodentium than those of mutant Cnlp-/- mice that lack mCRAMP. Cnlp-/- mice developed significantly greater colon surface and crypt epithelial cell colonization, surface epithelial cell damage, and systemic dissemination of infection than Cnlp+/+ mice after oral infection with C. rodentium. Moreover, Cnlp+/+ mice were protected from oral infections with C. rodentium inocula that infected the majority of Cnlp-/- mice. These results establish cathelicidin as an important component of innate antimicrobial defense in the colon.

Animals↗
PubMed1980

Effects of chenodeoxy- and ursodeoxycholic acid on absorption, secretion and permeability in rat colon and small intestine.

The effect of equimolar concentrations of chenodeoxycholic (CDCA) and ursodeoxycholic acid (UDCA) on the colonic absorption of water, sodium and oxalate, and on the transmural potential difference was examined in the rat colon by an open perfusion technique. In addition, the ileal absorption of D-glucose, oxalate, water and sodium was measured in the presence and absence of CDCA and UDCA. CDCA reversed the absorption of water and sodium into secretion more effectively than UDCA Oxalate absorption and permeability of the colon measured by the disappearance of D-mannitol were enhanced by CDCA, but to a lesser extent by UDCA. The ileal absorption of water and sodium was nearly abolished by CDCA and inhibited to a lesser extent by UDCA in the presence of D-glucose in the perfusate. At equimolar concentrations, CDCA induced a more marked inhibitory effect on colonic function than UDCA. This quantitative difference may account for the less frequent side-effects of diarrhoea in cholelitholytic treatment with UDCA compared to CDCA.

Animals↗
PubMed2003

Molecular comparison of bacterial isolates from blood with strains colonizing pharynx and intestine in immunocompromised patients with sepsis.

Most causative organisms of sepsis in immunocompromised patients are the same species as those that colonize their own nasopharynx or intestinal tract. To determine whether the strains recovered from blood originate mainly from patients' own flora, isolates from blood and throat and/or stool were investigated by genomic analyses. Surveillance cultures of throat and stool were taken prospectively from cancer patients being treated with intensive chemotherapy followed by haematopoietic stem-cell transplantation. In those cases of sepsis in which the isolate from blood was the same species as that from the throat and/or stool, the genomic profiles of the isolates were compared by PFGE. Ten cases of blood culture-positive sepsis were documented in six of 14 subjects during a 2 year period; isolates of Pseudomonas aeruginosa, Staphylococcus epidermidis, Enterococcus sp., viridans streptococci and Fusobacterium sp. were recovered from blood. In five of seven cases in which the blood isolate was the same species as that from the throat or stool, the genotypes of the isolates from both sites were identical. In the majority of immunocompromised patients, the causative organisms of bloodstream infections originated mainly from their own flora.

Adolescent↗
PubMed2004

Abnormal Paneth cell granule dissolution and compromised resistance to bacterial colonization in the intestine of CF mice.

Paneth cells of intestinal crypts contribute to host defense by producing antimicrobial peptides that are packaged as granules for secretion into the crypt lumen. Here, we provide evidence using light and electron microscopy that postsecretory Paneth cell granules undergo limited dissolution and accumulate within the intestinal crypts of cystic fibrosis (CF) mice. On the basis of this finding, we evaluated bacterial colonization and expression of two major constituents of Paneth cells, i.e., alpha-defensins (cryptdins) and lysozyme, in CF murine intestine. Paneth cell granules accumulated in intestinal crypt lumens in both untreated CF mice with impending intestinal obstruction and in CF mice treated with an osmotic laxative that prevented overt clinical symptoms and mucus accretion. Ultrastructure studies indicated little change in granule morphology within mucus casts, whereas granules in laxative-treated mice appear to undergo limited dissolution. Protein extracts from CF intestine had increased levels of processed cryptdins compared with those from wild-type (WT) littermates. Nonetheless, colonization with aerobic bacteria species was not diminished in the CF intestine and oral challenge with a cryptdin-sensitive enteric pathogen, Salmonella typhimurium, resulted in greater colonization of CF compared with WT intestine. Modest downregulation of cryptdin and lysozyme mRNA in CF intestine was shown by microarray analysis, real-time quantitative PCR, and Northern blot analysis. Based on these findings, we conclude that antimicrobial peptide activity in CF mouse intestine is compromised by inadequate dissolution of Paneth cell granules within the crypt lumens.

Animals↗
PubMed2001

Early phase of intestinal mantle cell lymphoma: a report of two cases associated with advanced colonic adenocarcinoma.

Intestinal mantle cell lymphoma characteristically produces multiple polyps, a finding reported as multiple lymphomatous polyposis. The early stages of intestinal mantle cell lymphoma before polyp formation and the pattern of initial lymph node invasion, however, have not been described. We recently encountered two cases of intestinal mantle cell lymphoma in their early development found incidentally associated with advanced colonic adenocarcinoma. We present herein the clinical, histopathological, immunohistochemical, and molecular genetic features of these two cases. In one case, a single polypoid mass was found with invasion limited to mucosa and submucosa of the terminal ileum and without lymph node compromise. In the second case, there were multiple mucosal aggregates of neoplastic cells without formation of polyps. Regional lymph nodes in the latter case showed either partial or complete involvement by lymphoma. In both cases, immunohistochemistry (CD20+, CD5+, cyclin D1+, CD10-, and CD23-), and demonstration of clonal immunoglobulin heavy chain and bcl-1 gene rearrangements by PCR analysis confirmed the diagnosis of mantle cell lymphoma.

Adenocarcinoma↗
PubMed1992

Concurrent adenocarcinoma of the colon and chronic intestinal parasitoses: a case report.

A 25-year-old patient presented with recurrent bloody diarrhoea associated with intestinal parasitoses. Radiography and tissue histology confirmed the diagnosis of an annular colonic adenocarcinoma. The incidence and management of colonic malignancy in young Africans is discussed in the light of its described associationship with protozoal/helminthic parasitoses.

Adenocarcinoma↗
PubMed2000

Colonization of the intestinal tract by Clostridium perfringens and fecal shedding in diet-stressed and unstressed broiler chickens.

Commercial broiler chicks were given a three-strain composite of bacitracin-resistant Clostridium perfringens by oral gavage and were sampled periodically to determine the dynamics of C. perfringens colonization of the intestinal tract of broiler chickens and fecal shedding. After gavage, the chicks were divided into two groups and placed in isolators, one group received a traditional corn-based diet, and the other group received the same diet supplemented with 50% rye to place the birds under dietary stress. The numbers of bacitracin-resistant C. perfringens in various parts of the intestinal tract, liver, and feces were determined using a selective plating medium containing bacitracin. In chickens on the corn-based or 50% rye diet, C. perfringens was isolated infrequently from the various parts of the intestinal tract, liver, or fecal droppings during the first 36 h following the last gavage. For the 24 chickens on each of the two diets that were sampled from 2 to 21 d after gavage, C. perfringens was recovered more frequently from the crop, proventriculus, duodenum, jejunum, ileum, ceca, and feces, but not the gizzard, of birds on the 50% rye diet as compared to those on the corn-based diet. From 2 to 21 d, the intestinal numbers of C. perfringens in contaminated birds on the corn-based diet were < or =log10 6.2 and did not increase in any portion of the intestinal tract. Numbers of C. perfringens during this time period increased 3.3 to 4.9 log factors in the ileum, ceca, and feces of birds on the 50% rye diet to as high as log10 7.1 to 7.9 at 21 d. This study confirms that addition of rye to the diet of chickens can increase the numbers of C. perfringens in the ceca of broiler chickens and extends these findings to demonstrate increases in the numbers and frequency of recovery of C. perfringens in other parts of the intestinal tract.

Animal Feed↗
PubMedDate not supplied

Colonization of the intestine of turkey embryos exposed to Mycoplasma iowae.

Eight-day-old turkey embryos were inoculated into the yolk sac with 3 X 10(5) colony-forming units of Mycoplasma iowae strain D112 in order to study the growth-depressing effect, the histopathological changes, and colonization of the intestinal tract. The embryo: egg weight ratio was significantly lower in the inoculated eggs than in controls. Histologically, there were infiltrations in parenchymatous organs and chorioallantoic membranes with heterophilic granulocytes. M. Iowae was demonstrated on the intestinal mucosa by antibody fluorescent microscopy and by transmission electron microscopy. Attaching mycoplasmas had a distinct morphology; the segment in contact with enterocytes was cone-shaped and had finely granulated cytoplasma which was abruptly separated from the distal coarsely granulated area. We conclude that M. iowae has a predilection for the intestinal tract of avian hosts.

Animals↗
PubMed2005

Differences in the effects of age on intestinal proliferation, crypt fission and apoptosis on the small intestine and the colon of the rat.

The increase in gastrointestinal epithelial tissue mass and the development of the gut can occur through three main mechanisms, namely elevated cell production from the intestinal crypts, by raised crypt number, which occurs through the process of crypt fission or by altered apoptosis. The small bowel and the colon have various rates of these, which were studied in rats of various ages. Wistar rats were fed ad libitum, and were killed at 3, 4, 6, 9, 12, 18, 26 and 48 weeks of age. Tissue was later stained and microdissected and the number of native mitoses and apoptotic figures per crypt and the percentage of crypts in fission were determined. There was an almost linear increase in body weight from 3 to 9 weeks, followed by a more gradual rise until 18 weeks. The weight of the stomach and the small intestine reached maximum values at 9 weeks, whereas the caecum and the colon approached this at 12 weeks. Mitotic activity per crypt in the small intestine increased from 3.8 +/- 0.1 at 3 weeks to 7.8 +/- 0.4 mitoses per crypt (P < 0.001) at 9 weeks and then decreased slightly; crypt fission increased from 4.6% +/- 0.8 at 3 weeks to 8.4 +/- 0.9% at 6 weeks and then decreased gradually reaching a value of 1.5 +/- 0.4% at 48 weeks. Apoptosis also peaked at 6 weeks and was then very low. In the colon, the proliferation decreased from 4.2 +/- 0.2 mitoses per crypt in the young (3 weeks) rat and reached a plateau by 9 weeks (2.5 +/- 0.1 mitoses per crypt, P < 0.001). Crypt fission also declined rapidly in the first 9 weeks (from 67.6 +/- 4.2 to 23.1 +/- 4.6%, P < 0.01) and then continued to decline, although at a lower rate. The crypt fission index at 48 weeks was 9.8 +/- 1.0. Apoptosis in the colon persisted throughout the duration of the study, 0.19 +/- 0.06 apoptotic bodies per crypt were seen at week 48. The development of the small intestine is more dependent on cell proliferation, whereas in the colon crypt fission is far more predominant, with the colon having fission indices approximately six times greater than those of the small intestine. Proliferative activity in the colon was approximately half that of the small intestine.

Aging↗
PubMed1996

Colonization by lactobacilli of piglet small intestinal mucus.

The colonization potential of lactobacilli was investigated using small intestinal mucus extracts from 35-d-old pigs. Mucus-secreting tissue from the small intestine of piglets was gently rinsed to remove contents and then shaken in buffer to release mucus from the surface. Numbers of lactobacilli in different portions of the small intestine of 35-d-old pigs were enumerated. Also, mucus isolated from the small intestine of pigs was investigated for its capacity to support the growth of lactobacilli. Results indicated that Lactobacillus spp. inhabit the mucus layer of the small intestine and can grow and adhere to ileal mucus. From adhesion studies of Lactobacillus fermentum 104R to mucus analysed by Scatchard plot, it is suggested that an associating system showing positive cooperativity is involved. Proteinaceous compounds(s) involved in the adhesion to mucus were detected in the spent culture fluid from the growth of strain 104R. Studies are continuing in order to identify and characterize the adhesion-promoting protein(s). From the data, it is proposed that lactobacilli colonize the mucus layer of the small intestine of pigs.

Animals↗
PubMed1983

Interindividual variation in the activity of O6-methyl guanine-DNA methyltransferase and uracil-DNA glycosylase in human organs.

As a step towards understanding the significance of DNA repair enzymes in the protection against genotoxic and carcinogenic agents, we have examined the activity of O6-methyl-guanine-DNA methyltransferase and uracil-DNA glycosylase in adult human liver, stomach, small intestine and colon. Liver had on average a 5- to 8-fold higher activity of O6-MeG-DNA methyltransferase than the other organs and showed about an 8-fold inter-individual variation. In colon and small intestine an even larger inter-individual variation was observed (10- and 40-fold, respectively). In two colon tumors examined the activity of O6-MeG-DNA methyltransferase was several fold higher than in non-neoplastic colon mucosa from the same individuals, while uracil-DNA glycosylase activity was essentially equal in neoplastic and non-neoplastic tissues. O6-MeG-DNA methyltransferase activities in two gastric tumors examined were not higher than in average non-neoplastic tissue. In general the activity of uracil-DNA glycosylase did not correlate with the O6-MeG-DNA methyltransferase activity. The inter-individual variation of this enzyme in the activity was only 3-fold in liver and normal stomach, but varied 5.5 and 60-fold in colon and small intestine, respectively. In conclusion, we have found that O6-MeG-DNA methyltransferase as well as uracil-DNA glycosylase activity vary considerably between different tissues as well as between different individuals. Whether this variation has a genetic basis or reflects variation in 'life style' is not known.

Adolescent↗