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PubMed1992

Antibodies to outer membrane proteins of Vibrio cholerae induce protection by inhibition of intestinal colonization of vibrios.

An antiserum was raised against the outer membrane (OM) preparation of a Vibrio cholerae 01 strain (Classical, Ogawa) and rendered specific for the outer membrane proteins (OMPs) by absorption with its lipopolysaccharide (LPS). The anti-OMP serum showed reactivity against OM preparations of other 01 and non-01 V. cholerae strains in enzyme-linked immunosorbent assay. The antiserum also induced significant protection against V. cholerae challenge in the suckling mouse model. This protection was found to be independent of biotype, serotype as well as serovar of the challenge organism and was demonstrable even at subagglutinating dilutions of antiserum. The Fab (IgG) fragment, prepared from the anti-OMP serum, also induced passive protection in similar experiments. Further studies demonstrated that the anti-OMP serum as well as its Fab (IgG) fragment markedly inhibited the intestinal colonization of a highly colonizing V. cholerae 01 strain A17 (El Tor, Ogawa). These results highlight the importance of V. cholerae OMPs in immunoprophylaxis against cholera.

Animals↗
PubMed1997

Dietary calcium inhibits the intestinal colonization and translocation of Salmonella in rats.

BACKGROUND & AIMS: Dietary calcium decreases the cytotoxicity of intestinal contents and intestinal epitheliolysis by precipitating cytotoxic surfactants such as bile acids. A decreased luminal cytotoxicity might not only strengthen the barrier function of the gut mucosa but also reinforce the protective, endogenous microflora. We hypothesized, therefore, that dietary calcium increases the resistance to intestinal infections. METHODS: Rats on a low-, medium-, or high-calcium purified diet were orally infected with a single dose of Salmonella enteritidis. The kinetics of fecal Salmonella excretion was studied to determine the colonization resistance. Intestinal bacterial translocation was quantitated by measuring urinary oxidation products of nitric oxide (NOx) excretion and culturing bacteria from tissues. RESULTS: Compared with the low-calcium group, the medium- and high-calcium diet-fed rats had a substantially improved colonization resistance. Calcium supplementation also reduced translocation of Salmonella, considering the diminished urinary NOx excretion and viable Salmonella counts in the Ileal Peyer's patches and spleen. Dietary calcium decreased the bile acid concentration and cytotoxicity of fecal water. Several indicators of fecal bacterial mass were significantly increased by supplemental calcium. CONCLUSIONS: Dietary calcium improves the colonization resistance and reduces the severity of gut-derived systemic infections, which is probably attributable to its luminal cytoprotective effects.

Animals↗
PubMedDate not supplied

Intestinal colonization and antibody response.

Rapid bacterial colonization of the gastrointestinal tract takes place immediately after birth. Only a few of the Escherichia coli strains colonizing the gut of healthy full-term neonates expressed MS pili. On the other hand, most E. coli strains isolated carried MR pili resembling the P-fimbriae which are a known virulence factor for pyelonephritogenic E. coli. The presence of serum antibodies against pili and K antigens of E. coli after vaccination did not influence the capacity of E. coli to colonize and persist in the intestine of experimental animals.

Animals↗
PubMed1990

Escherichia coli F-18 makes a streptomycin-treated mouse large intestine colonization factor when grown in nutrient broth containing glucose.

Escherichia coli F-18 FimA-, a type 1 fimbria-less derivative of a normal human fecal isolate, E. coli F-18, has previously been shown to be as good a colonizer of streptomycin-treated mouse large intestine as its parent, suggesting that type 1 fimbriae are not necessary in this process. In this study it was found that when E. coli F-18 FimA- was grown standing overnight at 37 degrees C in nutrient broth, it remained uniformly suspended; however, when grown in nutrient broth containing 1% (wt/wt) D-glucose, it settled to the bottom of culture tubes. Settling was associated with the formation of clumps (microcolonies) of more than 10 cells each. The effect of glucose could be partially reversed by growing E. coli F-18 FimA- in nutrient broth containing 1% D-glucose supplemented with cyclic AMP (greater than or equal to 1 mM). A reduced-settling mutant of E. coli F-18 FimA-, E. coli F-18 FimA- Set-, selected after Tn5 mutagenesis, was found to be a poor colonizer of streptomycin-treated mouse large intestine when fed to mice simultaneously with the parent strain. These results suggest that glucose-induced settling is, at least in part, regulated in a way related to catabolite repression and that the ability of E. coli F-18 FimA- to form microcolonies plays an important role in its ability to colonize streptomycin-treated mouse large intestine.

Animals↗
PubMed1981

Campylobacter fetus ss. Jejuni, a newly recognized enteric pathogen: morphology and intestinal colonization.

Campylobacter fetus ss. jejuni has recently been recognized as a frequent enteric pathogen of man. Although long known as a significant pathogen of domestic animals, little is known regarding mechanisms of colonization and pathogenesis. In an effort to study the colonization and morphology of this organism, we used scanning electron microscopy to examine ilea and colons from mice in which a human isolate of C. fetus ss. jejuni had been inoculated. When inoculated into the ileum of the mice, a transient colonization was observed by 24 hours and had disappeared by 48 hours. Colonization of the colon first appeared at 48 hours and persisted at least three weeks. When inoculated directly into the colon, colonization appeared within 24 hours in the colon and persisted at least 16 days. Severe colonic necrosis and mucosal degeneration were observed in colons only in those mice which were inoculated via the colon. In the infected colons, the C. fetus ss. jejuni organisms were enmeshed in a fibrous network which may play a role in the attachment of bacteria to the mucosal surface. Differences between the morphology of C. fetus ss. jejuni in the mouse model and that found in pure culture were observed and may represent distinct tissue and culture phases of growth.

Animals↗
PubMed1993

Characteristics of Vero cytotoxin producing Escherichia coli associated with intestinal colonization and diarrhea in calves.

Isolates of Escherichia coli which produce Vero cytotoxin (VTEC) were obtained during 1983-1989 from calves raised in 5 north-central states of the USA. All of the calves experienced intestinal epithelial colonization by VTEC, diarrhea or both; twelve of the calves had bloody diarrhea. Twenty one isolates were serogroup O111 and the others were O103, O69, O45, 026, O5, or non-typable (4 isolates). All but one of the isolates hybridized with the CVD419 probe which identifies most VTEC strains. Thirty two isolates hybridized with the VT1 probe, 3 with both the VT1 and VT2 probes, and one with neither probe. The culture filtrate of the VT probe negative isolate was partially neutralized by SLT I monoclonal antibody. For the other isolates, the results of toxin neutralization by anti-SLT I and anti-SLT II monoclonal antibodies corresponded exactly with the VT1 and VT2 probe hybridization results. Three of the strains adhered in a localized manner to HEp-2 cells and Intestine 407 cells.

Animals↗
PubMed1987

Demonstration of a flagellar antigen shared by a diverse group of spiral-shaped bacteria that colonize intestinal mucus.

Western blot analysis showed that there is little immunological cross-reactivity of the human pathogens Campylobacter jejuni and Campylobacter coli with Campylobacter pyloridis, except for a very strong cross-reaction between the flagellins. This same antigenic cross-reaction was found with two isolates of gram-negative spiral microaerophilic bacteria that are known to colonize the intestinal mucosa of rodents, but not with the flagellins of a number of other motile bacteria. It is proposed that this shared flagellin antigen may be important structurally and functionally.

Animals↗
PubMed1990

Observations on the intestinal colonization by Pseudomonas aeruginosa in newborn infants.

We studied the intestinal flora of 23 newborns, whose meconium had yielded a pure culture of Pseudomonas aeruginosa on blood agar medium. Twelve infants had a single serotype of P. aeruginosa in their meconium, 10 had a second serotype and the last infant was carrying three distinct ones. The maximum levels of P. aeruginosa observed during the first week of life were variable among the infants: 1 x 10(3) to 1 x 10(10) CFU/g of stools. The levels diminished progressively afterwards, and after 1 year of age only 1 of the 13 infants examined remained a carrier of P. aeruginosa. In 11 infants a second or a third serotype occurred during the course of the study. The serotypes that appeared secondarily always disappeared before the initial ones. Antibiotics: ampicillin + gentamicin or cefotaxime + netilmicin and colistin which were given to 8 infants had no clear effect on P. aeruginosa levels. Four infants had delayed colonization by Escherichia coli of greater than or equal to 10 days. All 4 had high levels of P. aeruginosa: 1 x 10(7) to 1 x 10(10) CFU/g stool, and antibiotic therapy, rendering it impossible to assess which was the cause of this delay. This colonization by P. aeruginosa did not lead to any clinical trouble.

Cefotaxime↗
PubMed1989

Comparison of muscarinic cholinergic and alpha adrenergic receptors in canine ileum, colon, intestinal urinary reservoirs and bladder.

The muscarinic cholinergic (MCh) and alpha 2 adrenergic receptor densities in canine ileum, colon, ileal and colonic urinary reservoirs and bladder were determined using radioligand receptor binding methods in order to provide a rational basis for pharmacologic management of urinary incontinence following bladder replacement with intestinal segments. Muscarinic cholinergic and alpha 2 adrenergic receptor binding sites were studied in these tissues using saturation experiments with 3H-NMS and 3H-rauwolscine, respectively. The mean equilibrium dissociation constants for 3H-NMS binding (0.13 to 0.17 nM) in these tissues were similar (p greater than 0.05) indicating homogeneity of muscarinic cholinergic binding sites. The mean equilibrium dissociation constants for 3H-rauwolscine binding (1.27 to 1.98 nM) in these tissues were also similar (p greater than 0.05). A substantial density of MCh (1.06 to 1.22 fmol/mg. wet wt.) and alpha 2 adrenergic (0.47 to 1.11 fmol/mg. wet wt.) binding sites was identified in the intestinal tissues assayed. The density of ileal and colonic MCh and alpha 2 adrenergic binding sites was not altered following construction of urinary intestinal reservoirs. The presence of a substantial density of MCh and alpha 2 adrenergic binding sites in the intestinal tissues suggests that MCh and alpha 2 adrenergic analogs may be utilized for the management of urinary incontinence following bladder replacement with intestinal urinary reservoirs.

Animals↗
PubMed1992

Intestinal colonization & production of diarrhoea by enteroadherent-aggregative Escherichia coli.

The ability of HEp-2 cell adherent Esch. coli of aggregative phenotype (EA-Agg EC) to cause diarrhoea and to colonize the bowel of rabbits was studied. Thirty six rabbits were challenged with one of three EA-Agg EC strains (F23A; H766C and F17A-15, 3 and 3 rabbits respectively) or a control strain (K12-15 rabbits) in reversible ileal-tie in adult rabbit diarrhoea (RITARD) model. The animals were sacrificed 72 h post challenge. Severe diarrhoea occurred in greater number of F23A challenged rabbits than the controls (P < 0.05). Mucosal cultures from proximal and distal small intestine and colon yielded about 1000 times more Esch. coli in the test than control rabbits (P < 0.001 in each case). EA-Agg EC were consistently grown from mucosa in the test rabbits who commonly showed mild to moderate villous stunting and grade + to nuclear fragmentation (karyorrhexis) in the small and large bowel epithelium. The control animals had either normal villi or very mild villous stunting. Results comparable to F23A were obtained with the other two EA-Agg EC strains tested in a smaller number of animals.

Animals↗
PubMed1978

Intestinal colonization and virulence of Salmonella in mice.

Within 3 h after oral challenge of mice with Salmonella typhimurium, foci of infection developed in the Peyer's patches of the small intestine. The numbers of organisms in the cecum, although in excess of those found in the small intestine, were not firmly associated with the cecal wall but were present largely in the cecum's contents. The Peyer's patches at first were remarkably incapable of eliminating even small numbers of Salmonella, but at about 7 days after infection developed the ability to eliminate a less virulent strain of S. typhimurium. Selected strains of Salmonella of varied virulence, and hybrid Escherichia coli/Salmonella typhimurium with varied O-antigens, revealed that those of low virulence could multiply within the intestinal Peyer's patches at nearly the same rate as a virulent strain, and the ability to multiply within the Peyer's patches was not dependent upon O-antigen type or smooth lipopolysaccharide. The ability of these strains to adhere to intestinal mucosa in vitro did not reflect on their ability to colonize the Peyer's patches, although strains of high in vitro adhesive ability appeared in greater numbers initially after oral challenge. Anti-O serum, ineffective in reducing the in vitro adhesive ability of virulent S. typhimurium, when given with the oral challenge prevented Peyer's patch colonization but was unable to prevent the appearance of a systemic infection. Anti-H serum, although effective in vitro in preventing adherence, had no effect in vivo. These experiments suggest that adhesiveness is neither essential nor sufficient for the virulence of Salmonella and that the usual development of a systemic infection after colonization of the small intestinal Peyer's patches may be subverted by the presence of O-antibody.

Antibodies, Bacterial↗
PubMed1986

Factors responsible for increased susceptibility of mice to intestinal colonization after treatment with streptomycin.

Streptomycin sulfate (5 mg/ml) was added to the drinking water of Swiss white mice. After treatment for 1 week, the mice were challenged orogastrically with 10(8) Pseudomonas aeruginosa cells. The organism failed to multiply in the intestinal tract of either treated or untreated animals, but could be recovered from contents and tissues after 48 h. In a previous study, Salmonella typhimurium was shown to multiply in the intestines of streptomycin-treated but not untreated mice when 10(3) organisms were used as inoculum. Streptomycin administration had little effect on Eh, protein or carbohydrate concentrations of cecal contents, or intestinal motility. However, it caused a statistically significant increase in water content and pH of contents and a decrease in the concentrations of acetic, propionic, butyric, and valeric acids. S. typhimurium multiplied in pooled cecal contents obtained from both streptomycin-treated and untreated animals, but its multiplication rate and total populations were significantly greater in contents from treated animals. P. aeruginosa did not multiply in contents from either treated or untreated mice. Similar results were obtained when the organisms were inoculated into nutrient broth adjusted to simulate the pH levels and volatile fatty acid (VFA) concentrations in cecal contents of treated and untreated mice. The addition of brain heart infusion broth to cecal contents from untreated animals, in concentrations that support multiplication of S. typhimurium and P. aeruginosa, did not reverse inhibition. The addition of VFA to cecal contents from treated animals to equal the concentration in cecal contents from untreated animals caused inhibition of a magnitude observed in cecal contents from untreated animals. The results indicate that VFA operating at the pH level of cecal contents of conventional mice inhibit the multiplication of both S. typhimurium and P. aeruginosa and restrict colonization of the intestine by these organisms. The decrease in VFA concentrations that occurs as a result of streptomycin administration adequately explains the increased susceptibility of treated mice to colonization with S. typhimurium. It does not explain the increased susceptibility of treated mice to P. aeruginosa colonization, however.

Animals↗
PubMed1984

The uptake of lead by small intestine, colon and gallbladder of the guinea pig in vivo.

The binding and uptake of lead by the jejunal, colonic and gallbladder epithelium of guinea pig has been investigated by electron microscopy. Binding occurred rapidly, the most marked by the microvilli was by the jejunum, followed by colon and gallbladder. The tracer was subsequently internalised in small membrane bound vesicles and smooth endoplasmic reticulum. By 30 min, it appeared in multivesicular bodies at all three sites.

Animals↗