Helicobacter pullorum outbreak in C57BL/6NTac and C3H/HeNTac barrier-maintained mice.

Helicobacter pullorum is a bacterial pathogen in humans. By using microaerobic culture techniques, H. pullorum was isolated from the feces of barrier-maintained mice and identified, on the basis of biochemical, restriction fragment length polymorphism, and 16S rRNA gene sequence analyses. This finding presents an opportunity to study H. pullorum pathogenesis in mice.

High-salt diet induces gastric epithelial hyperplasia and parietal cell loss, and enhances Helicobacter pylori colonization in C57BL/6 mice.

A high-salt diet in humans and experimental animals is known to cause gastritis, has been associated with a high risk of atrophic gastritis, and is considered a gastric tumor promoter. In laboratory rodents, salt is known to cause gastritis, and when coadministered, it promotes the carcinogenic effects of known gastric carcinogens. Because Helicobacter pylori has been associated with a progression from gastritis to gastric cancer, we designed a study to determine whether excessive dietary NaCl would have an effect on colonization and gastritis in the mouse model of H. pylori infection. Seventy-two, 8-week-old female C57BL/6 mice were infected with H. pylori strain Sydney, and 36 control mice were dosed with vehicle only. One-half of the infected and control mice were fed a high-salt diet (7.5% versus 0.25%) for 2 weeks prior to dosing and throughout the entire experiment. Twelve infected and 6 control animals from the high-salt and normal diet groups were euthanized at 4, 8, and 16 weeks. At 8 and 16 weeks postinfection (WPI), the colony-forming units per gram of tissue were significantly higher (P < 0.05) in the corpus and antrum of animals in the high-salt diet group compared with those on the normal diet. Quantitative urease was significantly higher (P < 0.05) at 4 and 8 WPI in the corpus and antrum of animals on the high-salt diet when compared with controls. At 16 WPI, mice in both the normal and the high-salt diet groups developed moderate to marked atrophic gastritis of the corpus in response to H. pylori infection. However, the gastric pits of the corpus mucosa in mice on the high-salt diet were elongated and colonized by H. pylori more frequently than those in mice on the normal diet. The high-salt diet was also associated with a significant increase in proliferation in the proximal corpus and antrum and a multifocal reduction in parietal cell numbers in the proximal corpus, resulting in the elongation of gastric pits. We conclude that excessive NaCl intake enhances H. pylori colonization in mice and in humans and that chronic salt intake may exacerbate gastritis by increasing H. pylori colonization. Furthermore, elevated salt intake may potentiate H. pylori-associated carcinogenesis by inducing proliferation, pit cell hyperplasia, and glandular atrophy.

Histochemistry in the diagnosis of early prostatic carcinoma.

Twenty-seven prostatic adenocarcinomas, most of them well differentiated, were examined for acid mucoproteins by the Kreyberg and alcian blue-periodic acid-Schiff methods. Seventeen (63 per cent) showed varying amounts of positive material in the lumens of the malignant glands. The procedures can be performed on routinely fixed and paraffin blocked tissues, and are useful in confirming the presence of malignant disease in equivocal cases in which crush artifact or small amounts of very well differentiated tumor acini are present.

Genome conservation in Helicobacter mustelae as determined by pulsed-field gel electrophoresis.

Genomic DNA from 15 strains of Helicobacter mustelae was subjected to pulsed-field gel electrophoresis (PFGE) after digestion with PacI and SfiI. H. mustelae genome DNA appeared very similar in all strains examined, whether isolated from ferrets or mink or from animals bred in either the USA or in the UK. The H. mustelae genome size was estimated to be 1.7 Mb, similar in size to that of H. pylori. A minor difference in PacI PFGE pattern and genome size was observed between rifampicin-resistant and rifampicin-susceptible derivatives of H. mustelae F251. Another minor difference in genome pattern based on PFGE with SfiI was observed between an H. mustelae strain used to experimentally infect four ferrets which resulted in loss of an SfiI site in strains obtained from the newly infected ferrets. Thus, although minor differences in PFGE pattern were noted, H. mustelae lacks the genomic diversity observed in H. pylori.

In-vitro hepatotoxic factor in Helicobacter hepaticus, H. pylori and other Helicobacter species.

Several inbred strains of mice in closed breeding colonies were found to have spiral-shaped bacteria associated with active, chronic hepatitis. A new species of Helicobacter, H. hepaticus, was isolated from the infected livers of some strains of mice. Other strains of mice were colonised with H. hepaticus in the caecum and colon, but not the liver. Filtersterilised supernatant fluid from five strains of H. hepaticus was tested in a mouse liver cell line (ATCC no. CCL 9.1) for cytotoxic activity. All strains produced a toxic factor causing morphological changes in the cells at dilutions up to 1 in 1000. Toxicity was observed after exposure to the supernatant fluid for 48-72 h. Other Helicobacter spp. that also produced the cytopathic effect (CPE) in the liver cell line were H. felis, H. acinonyx, H. pylori and one strain of H. mustelae. "Helicobacter rappini" and H. muridarum did not cause CPE in the liver cells. The soluble factor was stable at 4 degrees C for up to 3 months. It was also stable at 56 degrees C for 30 min, but was inactivated by boiling for 15 min. It was inactivated by incubation with trypsin. A partially purified preparation of the cytotoxin had a mol. wt of c. 100,000 and did not have urease activity. The cytotoxin produced by H. hepaticus did not cause vacuole formation in HeLa cells.

Haemagglutination profiles of Helicobacter species that cause gastritis in man and animals.

Thirty-five Helicobacter pylori isolates, 21 H. mustelae isolates and four strains of H. felis were compared for their ability to agglutinate red blood cells (RBCs). Isolates were examined in a slide haemagglutination assay with RBCs from 11 animal species, including rodents, carnivores and primates, as well as man. RBCs were agglutinated by 65-90% of H. mustelae isolates and 16-57% of H. pylori isolates. Treatment of H. mustelae with pronase and heat inhibited haemagglutination (HA) whereas heating only of H. pylori inhibited HA. Treatment of all strains of H. mustelae with trypsin inhibited agglutination of human RBCs; 75% of the treated strains did not agglutinate ferret RBCs. These results suggested that protein(s) may be important haemagglutinins for these bacteria. Variable HA profiles together with varying results after treatment of RBCs with fetuin, D-mannose, and neuraminidase suggested that multiple receptors may be involved in HA reactions with H. pylori and H. mustelae. The observation that H. mustelae and H. pylori agglutinated RBCs of several species and closely adhered to gastric epithelium supported the hypothesis that adherence plays a role in the colonisation and pathogenicity of H. mustelae and H. pylori. H. felis did not adhere to gastric epithelium and did not agglutinate RBCs of any species; nevertheless, H. felis can readily colonise and produce gastritis in several mammals.

Unilateral glomerulonephritis.

Three patients had unilateral glomerulonephritis. In two, the protected kidney was associated with stenosis of its renal artery, and in the third patient, a hydronephrotic kidney was spared. These clinical examples of unilateral glomerulonephritis and similar experimental models illustrate the effect of hemodynamic and hydrostatic influence in the manifestation of glomerulonephritis. Glomerulonephritis associated with unilateral arterial or ureteral disease may cause clinical confusion and error in diagnosis and treatment.

Ranitidine bismuth citrate and clarithromycin, alone or in combination, for eradication of Helicobacter mustelae infection in ferrets.

OBJECTIVE: To determine whether ranitidine bismuth citrate, clarithromycin, or a combination of ranitidine bismuth citrate and clarithromycin would be efficacious in eradication of Helicobacter mustelae infection in ferrets. ANIMALS: 60 seven-month-old ferrets. PROCEDURE: To determine dosages of clarithromycin and ranitidine bismuth citrate that would suppress growth of, but not eradicate infection with, H mustelae, ferrets (n = 6/group) were treated p.o. with clarithromycin or ranitidine bismuth citrate at various dosages. Efficacy of treatment was then determined by treating ferrets with clarithromycin alone, ranitidine bismuth citrate alone, or clarithromycin and ranitidine bismuth citrate. Gastric biopsy specimens were obtained before, during, and at various times after treatment and submitted for quantitative bacterial culture and histologic evaluation. Minimum concentrations of clarithromycin that inhibited 90% of the growth of isolates obtained before and after treatment were determined. RESULTS: Dosages of clarithromycin and ranitidine bismuth citrate that suppressed growth of H mustelae were 12.5 and 24 mg/kg of body weight, p.o., every 8 hours, respectively. Infection was not eradicated in ferrets treated with ranitidine bismuth citrate alone but was eradicated in all 6 ferrets treated with clarithromycin and ranitidine bismuth citrate and in 4 of 6 treated with clarithromycin alone. A decrease in susceptibility to clarithromycin was detected for H mustelae isolates obtained after treatment. Mild or moderate antral gastritis was observed even in ferrets from which infection was eradicated. CONCLUSIONS AND CLINICAL RELEVANCE: A combination of ranitidine bismuth citrate and clarithromycin was efficacious in eradicating H mustelae infection from ferrets.

Utilization of cholestyramine resin as a preventive treatment for antibiotic (clindamycin) induced enterotoxaemia in the rabbit.

Cholestyramine, an ion exchange resin shown to bind bacterial toxins, was utilized to treat rabbits with antibiotic induced enterotoxaemia. Three groups of 6 rabbits were administered 30 mg/kg clindamycin phosphate intravenously on day 1. One group was untreated; 2 groups were treated daily by gavage with 2 g cholestyramine in 20 ml water until day 21, starting on either day 1 or 3. Daily body weights, faecal output, faecal occult blood, food and water consumption, and body temperatures were determined. Four of 6 rabbits in the untreated group either died or were moribund and euthanased. There were no deaths in either treatment groups. Dramatic decreases in food consumption (86%), water consumption (62%), and faecal output (89%) were noted within 3 days after clindamycin administration in all groups. These parameters remained depressed throughout the study. There was no clear trend in body weight changes, body temperature, or faecal occult blood test results. Cholestyramine was effective in eliminating mortality associated with the intravenous administration of clindamycin and is recommended to prevent the development of enterotoxaemia when pyrogen testing or administering antibiotics known to induce the syndrome in rabbits.

Progressive proliferative and dysplastic typhlocolitis in aging syrian hamsters naturally infected with Helicobacter spp.: a spontaneous model of inflammatory bowel disease.

Helicobacter spp. have been implicated in a variety of gastrointestinal tract diseases, including peptic ulcer disease, gastric cancer, and inflammatory bowel disease (IBD), in humans and animals. Although most models of IBD are experimentally induced, spontaneous or natural models of IBD are rare. Herein, we describe a long-term study of chronic, progressive lesions that develop in the distal portion of the large bowel of unmanipulated Syrian hamsters naturally infected with Helicobacter spp. Twenty-four Syrian hamsters of three age groups (group A, 1 month [n = 4], group B, 7-12 months [n = 12], group C, 18-24 months [n = 12]), underwent complete postmortem examination. Results of microbial isolation and polymerase chain reaction and restriction fragment length polymorphism analyses confirmed the presence of Helicobacter spp. infection in the distal portion of the large bowel of all animals. Additionally, confounding pathogens, such as Clostridium difficile, Lawsonia intracellularis, and Giardia spp. that can cause proliferative enteritis, were absent in the hamsters of this study. Histopathologic scores for inflammation (P < 0.01), hyperplasia (P < 0.01), and dysplasia (P < 0.05) were significantly higher in the ileocecocolic (ICC) junction of animals in group C, relative to group A. Dysplastic lesions of various grades were detected in 5 of 11 hamsters in group C. Interestingly, the segment of the bowel that is usually colonized by Helicobacter spp. in hamsters had the most severe lesions. One hamster of group C developed a malignant fibrous histiocytoma, whereas another hamster developed a round cell sarcoma originating from the ICC junction. Thus, lesions in the distal portion of the large bowel of aging hamsters naturally colonized with Helicobacter spp. warrants developing the hamster as an animal model of IBD and potentially IBD-related cancer.

Rapid onset of ulcerative typhlocolitis in B6.129P2-IL10tm1Cgn (IL-10-/-) mice infected with Helicobacter trogontum is associated with decreased colonization by altered Schaedler's flora.

Infection with Helicobacter trogontum, a urease-positive helicobacter isolated from subclinically infected rats, was evaluated in B6.129P2-IL10(tm1Cgn) (interleukin-10(-/-) [IL-10(-/-)]) and C57BL/6 (B6) mice. In a first experiment, IL-10(-/-) mice naturally infected with Helicobacter rodentium had subclinical typhlocolitis but developed severe diarrhea and loss of body condition with erosive to ulcerative typhlocolitis within 1 to 3 weeks of experimental infection with H. trogontum. A second experiment demonstrated that helicobacter-free IL-10(-/-) mice dosed with H. trogontum also developed severe clinical signs and typhlocolitis within 2 to 4 weeks, whereas B6 mice colonized with H. trogontum were resistant to disease. In a third experiment, using helicobacter-free IL-10(-/-) mice, dosing with H. trogontum resulted in acute morbidity and typhlocolitis within 8 days. Acute typhlocolitis was accompanied by signs of sepsis supported by degenerative hemograms and recovery of Escherichia coli and Proteus spp. from the livers of infected mice. Quantitative PCR data revealed that H. rodentium and H. trogontum may compete for colonization of the lower bowel, as H. trogontum established higher colonization levels in the absence of H. rodentium (P < 0.003). H. trogontum-induced typhlocolitis was also associated with a significant decrease in the levels of colonization by five of eight anaerobes that comprise altered Schaedler's flora (P < 0.002). These results demonstrate for the first time that H. rodentium infection in IL-10(-/-) mice causes subclinical typhlocolitis and that infection with H. trogontum (with or without H. rodentium) induces a rapid-onset, erosive to ulcerative typhlocolitis which impacts the normal anaerobic flora of the colon and increases the risk of sepsis.

Binding of Clostridium difficile cytotoxin and vancomycin by anion-exchange resins.

Cholestyramine and colestipol were tested for binding of Clostridium difficile cytotoxin with use of batch absorption and column chromatography. The toxin was bound by both resins and could not be eluted from cholestyramine with either an ionic of a pH gradient. Vancomycin bound to cholestyramine more strongly than to colestipol. Cholestyramine and vancomycin were also tested for therapeutic efficacy in the hamster model of clindamycin-induced cecitis. Both compounds delayed death and reduced levels of cytotoxin in stool; these effects were greatest for vancomycin. Use of the two compounds in combination reduced concentrations of biologically active vancomycin in stool, but the levels still exceeded the minimum inhibitory concentration for C. difficile. These data suggest that the therapeutic benefit of cholestyramine in some patients with antibiotic-associated pseudomembranous colitis is due to its binding of the C. difficile cytotoxin. Since anion-exchange resins also bind vancomycin, caution is necessary if resins are used concurrently with vancomycin for therapy.

Purification of Pseudomonas aeruginosa exotoxin by affinity chromatography.

Pseudomonas aeruginosa exotoxin A was purified by affinity chromatography from culture supernatants by elution of toxin from antitoxin immunoglobulin G-Sepharose 4B with 3 M NaSCN. The purity, toxicity, and enzymatic activity of exotoxin obtained were comparable to those of toxin purified by previously reported multiple-step procedures.

Partial purification and characterization of a cytotoxin from Clostridium difficile.

A trypsin-sensitive, heat-labile cytotoxin was purified from the supernatant of a culture of Clostridium difficile by a procedure that included ultrafiltration, precipitation with (NH4)2SO4, gel filtration, and ion-exchange chromatography. The procedure resulted in recovery of 20% of the cytotoxin and an estimated 1,500-fold increase in cytotoxic activity. The minimal amount of protein required to give an actinomorphic response in WI-38 cell cultures was 1.4 ng/ml. The estimated molecular weight of the cytotoxin is 240,000. A cytotoxin having similar properties was purified from the stool of a patient with antibiotic-associated pseudomembranous colitis by (NH4)2SO4 precipitation and gel filtration chromatography. This procedure resulted in a recovery of 26% of the cytotoxin, a 50-fold increase in cytotoxic activity, and a cytotoxic response with a minimum of 12.1 ng of protein/ml.

Serum antibody to Pseudomonas aeruginosa exotoxin measured by a passive hemagglutination assay.

A passive hemagglutination (PHA) assay for antibody to Pseudomonas aeruginosa exotoxin is described which utilizes chromic chloride-treated ovine erythrocytes coated with purified toxin. PHA antitoxin titers correlated well with those obtained by a cytotoxicity neutralization assay (r = 0.91, P less than 0.001), whereas the PHA assay was four to eight times as sensitive. The mean serum PHA titer of 16 patients convalescing from recent pseudomonas infections (log2 = 9.4 +/- 3.9) was significantly higher (P less than 0.001) than that of 17 healthy controls (2,7 +/- 2.6), and fourfold or greater rises were demonstrated in 5 of 7 patients examined sequentially. The lower levels of PHA antibody in sera from 11 of 17 controls suggested the acquisition of antitoxin secondary to asymptomatic infection.