Effects of ranitidine bismuth citrate on Helicobacter pylori motility, morphology and survival.

AIM: The effects of the anti-ulcer agents ranitidine bismuth citrate (RBC), ranitidine hydrochloride (R) and colloidal bismuth citrate (BC), on Helicobacter pylori motility, morphology and survival were examined to determine whether the clinical effectiveness of RBC might be linked to a specific action that inhibits bacterial motility. METHODS: H. pylori from patients with duodenal ulcer or non-ulcer dyspepsia were exposed to RBC and BC at bismuth concentrations ranging from 12.5 to 50 microg/mL, and R at ranitidine concentrations ranging from 12.5 to 50 microg/mL for a brief period (< 15 min), 6 h and 24 h. Bacterial motility was assessed with a Hobson BacTracker, bacterial morphology by transmission electron microscopy, and growth inhibition by counting colony-forming units. RESULTS: H. pylori motility was diminished with RBC and BC but not R. However, the effect of RBC was markedly greater than that of BC at each bismuth concentration and time of exposure tested: (i) brief exposure to RBC/bismuth 50 microg/mL but not to BC, resulted in a significant loss of motility without loss of viability or change in cell morphology, and (ii) bacteria were immobilized, and lost viability after exposure to RBC/bismuth 50 microg/mL for 24 h but not to BC. Morphological destruction caused by RBC differed from that by BC: after 24 h exposure to the highest concentration tested, cell fragmentation and flagella detachment occurred more frequently with BC than RBC, but the latter produced greater disruption of intracellular structures. CONCLUSIONS: RBC suppresses growth of H. pylori, and has a specific inhibitory effect on the bacterial motor mechanism. These pharmacological actions are likely to contribute to the clinical effectiveness of the agent.

Lansoprazole, clarithromycin and metronidazole for seven days in Helicobacter pylori infection.

BACKGROUND: This study determines the efficacy and safety of a 1-week triple therapy regimen of lansoprazole, clarithromycin and metronidazole in an area with a high prevalence of pre-treatment metronidazole-resistant strains of Helicobacter pylori. METHODS: Seventy-five H. pylori positive patients with gastritis or duodenal ulcer were entered into an open study of lansoprazole 30 mg o.m., clarithromycin 250 mg b.d. and metronidazole 400 mg b.d. H. pylori status was determined by CLOtest, histology, culture and by 13C-urea breath test (repeated > or = 28 days after treatment). RESULTS: Seventy-one patients completed the treatment and returned for follow-up. H. pylori was eradicated in 61 of 71 (86%) patients by per-protocol analysis, and in 61 of 75 (81%) patients by intention-to-treat analysis. H. pylori was eradicated in 12 of 16 (75%) patients with metronidazole-resistant strains compared with 22 of 24 (92%) in patients with metronidazole-sensitive strains of H. pylori (P = 0.14). Fourty-five patients reported at least one adverse event, and three patients stopped treatment due to them (two with headaches and one with diarrhoea). CONCLUSIONS: A 1-week course of lansoprazole 30 mg o.m., clarithromycin 250 mg b.d. and metronidazole 400 mg b.d. eradicates H. pylori in up to 86% of patients. It is of proven benefit in patients with pre-treatment metronidazole-resistant strains of H. pylori.

Two-week eradication regimen for metronidazole-resistant Helicobacter pylori.

At present there is no generally accepted treatment regimen for eradicating metronidazole-resistant Helicobacter pylori. This study determines the eradication rate after treatment with 40 mg omeprazole o.m. and 500 mg amoxycillin q.d.s. for 14 days, with 120 mg tripotassium dicitrato bismuthate q.d.s. for the first week (Days 1-7) and 750 mg ciprofloxacin b.d. for the second week (Days 8-14). Thirty patients (16 male, mean age 45 years, range 16-80 years) with duodenal ulcers (n = 18) or non-ulcer dyspepsia (n = 2) and metronidazole-resistant H. pylori detected by histology, culture, in vitro sensitivity tests and a positive 13C-urea breath test entered the study. Follow-up was by 13C-urea breath test at the end of treatment and at 1, 3, 6, and 12 months. Eradication was defined as a negative 13C-urea breath test at least 1 month after finishing treatment. H. pylori was successfully eradicated in 21/30 (71%) patients (median follow-up 10.2 months, range 4-12 months). A pre-treatment ciprofloxacin-resistant strain was isolated in 1/9 patients in whom eradication failed. Of 30 patients 29 completed the 2-week regimen; one patient experienced dizziness after 3 days of treatment. The most common side-effect was increased stool frequency (n = 6). This 2-week treatment regimen for metronidazole-resistant H. pylori is well tolerated and achieves an eradication rate of 70%.

Measurement of motility of Helicobacter pylori, Campylobacter jejuni, and Escherichia coli by real time computer tracking using the Hobson BacTracker.

AIMS: (1) To make precise measurements and comparisons of various aspects of motility of three gastrointestinal pathogens, Helicobacter pylori, Campylobacter jejuni, and Escherichia coli, in log phase growth; (2) to provide background information on motility data to study the influence of pH, viscosity, and chemotactic factors, thereby gaining a better understanding of bacterial pathogenesis. METHODS: Computer image processing technology and phase contrast microscopy (Hobson BacTracker) were used to measure several indices of bacterial motility in real time. Ten clinical isolates of each species in log phase liquid culture were studied. RESULTS: C jejuni moved fastest, with a median curvilinear velocity (CLV) of 38.76 microns/s (range 29.08 to 52.82). Next was H pylori, median CLV 25.02 microns/s (range 12.07 to 29.07). E coli was the slowest, median CLV 12.73 microns/s (range 8.20 to 18.04). The straight line velocities showed similar trends. Measurement of track linearity (TL) showed that C jejuni moved the straightest (TL 60.3%), H pylori moved in wide circles (TL 28.7%), and E coli showed spinning movement without much linear displacement (TL 18.3%). There were significant differences in these three variables between the species studied, but no significant differences in measurements of time and frequency of halts between movement runs. CONCLUSIONS: The BacTracker provides a useful technical aid for measuring several indices of bacterial motility objectively, reproducibly, and precisely, which is difficult to achieve without computer assistance. Accurate quantification of motility provides a basis for studying the factors which influence bacterial motility. It can provide phenotypic measurements of the effect of flagellar gene depletion.

Breakdown of gastric mucus in presence of Helicobacter pylori.

The potential of Helicobacter pylori to degrade gastric mucus was examined. Colonies of H pylori cultured from antral mucosal biopsy specimens of patients with non-autoimmune gastritis were washed with sterile saline, passed through a sterilisation filter, and the filtrate examined for urease, protease, and mucolytic activity. The filtrate failed to hydrolyse bovine serum albumin, or to degrade stable mucus glycoprotein structures of high particle weight that had been separated from human gastric mucus on Sepharose 2B. The high particle weight mucus glycoprotein was, however, extensively degraded when incubated with H pylori filtrate (which possessed urease activity) in the presence of 2 M urea, to release fragments of Mr approximately 2 X 10(6). The high particle weight mucus glycoprotein was also broken down to a comparable extent when incubated with Jack bean urease in the presence of 2 M urea, or 1 M ammonium carbonate, or 40 mM carbonate-bicarbonate buffer (pH 8.7), but not when treated with 4 M urea alone, or Jack bean urease alone. These results indicate that the loss of high particle weight mucus glycoprotein in gastric mucus from patients with gastritis and gastric ulcers is unlikely to be due to the mucolytic action of an extra-cellular protease produced by H pylori, but it may result from the destabilising effects of a carbonate-bicarbonate buffer, generated at the mucosal surface when H pylori urease hydrolyses transuded plasma urea.

Opsonophagocytosis of Campylobacter pylori.

The opsonic activity of human serum from various sources against Campylobacter pylori was compared. All sera, whether from control subjects with no symptoms of gastritis or peptic ulceration, or from symptomatic patients from whom C. pylori had or had not been isolated, opsonised C. pylori equally well. Opsonisation depended on the alternative pathway of complement activation but not on antibody. These findings suggest that antibody plays no role in protection against C. pylori and that the presence of antibody in patients' sera is mainly of diagnostic value.

The production and characterisation of rabbit antiserum and murine monoclonal antibodies to Haemophilus ducreyi.

Rabbit antiserum and murine monoclonal antibodies were raised against a strain of Haemophilus ducreyi. The antiserum gave high immunofluorescence titres and strong dot blot reactions with all H. ducreyi strains tested and the only cross reaction was with Bordetella pertussis. Three monoclonal antibodies, all of isotype IgG2a, also gave high immunofluorescence titres with H. ducreyi but did not cross react with any other species tested. Immunoblotting showed the monoclonal antibodies to react with a single polypeptide band of mol. wt 29,000 in the outer-membrane fraction of H. ducreyi. These antibodies have potential for use as diagnostic reagents and for investigating the pathogenicity of H. ducreyi.

Routine cleaning and the elimination of Campylobacter pylori from endoscopic biopsy forceps.

The effect of routine cleaning in removing Campylobacter pylori from the biopsy forceps of endoscopes has been examined in a series of 50 patients. Campylobacter pylori was isolated from the biopsies of 15 of the patients, while one of the 50 biopsy forceps washings yielded the organism after routine cleaning. This study suggests that there is a small chance of transmitting C. pylori by endoscopic equipment if cleaning is the only method of decontamination adopted.

N alpha-methylhistamine: association with Helicobacter pylori infection in humans and effects on gastric acid secretion.

Infection with the bacterium Helicobacter pylori is associated with altered gastric acid secretion and gastrointestinal disease. Recent work has suggested that N alpha-methylhistamine, produced by the bacterium and acting on histamine receptors in gastric tissue, might be involved. Gastric juice and tissue biopsies from infected patients have been analysed for the presence of N alpha-methylhistamine using a specific and sensitive assay based on gas chromatography mass spectrometry. N alpha-Methylhistamine was detected in five of seven samples of gastric juice from infected patients (5-180 pmol/ml) but was absent in nine uninfected subjects. The compound was not found in fundic and antral biopsies from both subject groups. Helicobacter pylori, cultured on agar and in broth with and without added histamine, was found not to produce detectable levels of N alpha-methylhistamine. Instillation of this compound at 10(-5) mol/l into the gastric lumen produced a significant increase in acid secretion in vivo while plasma gastrin concentration remained unchanged. N alpha-Methylhistamine in gastric juice appears therefore to be associated with infection, although this product is not generated directly by the bacterium. The concentrations found are below those required to affect acid secretion or gastrin production in vivo, although higher local concentrations may exist around a site of infection.

Motility of Helicobacter pylori in a viscous environment.

BACKGROUND: Patients with gastroduodenal disease produce gastric mucus of higher viscosity, and mucins that are of a smaller size, than normal. We have modelled these changes to the mucus layer in solutions of methylcellulose, and measured bacterial motility in biopsied mucus, to assess how they might influence the movements of Helicobacter pylori. METHODS: Motilities of Helicobacter pylori were measured in solutions of methylcellulose with molecular mass of 14 and 41 kDa, and in biopsied mucus with a Hobson BacTracker. Four parameters of bacterial motility were quantified: curvilinear velocity (CLV), path length, track linearity and curvature rate. RESULTS: All H. pylori were motile in methylcellulose solutions, and had optimal motilities at a viscosity of 3 cp (CLV in methylcellulose of 41 kDa, for instance, was 33 +/- 1.4 microm/s (mean +/- SEM) and the path length in methylcellulose of 41 kDa was 22.4 +/- 2 microm). At higher viscosities, mean CLVs, path lengths and curvature rates decreased, and track linearities increased in direct proportion to the increase in methylcellulose viscosity. Bacteria become non-motile at a viscosity of 50 cp in methylcellulose of 14 kDa, and at 70 cp in methylcellulose of 41 kDa. Mean CLVs, path lengths and curvature rates (but not track linearities) were greater in methylcellulose of 41 kDa than in methylcellulose of 14 kDa at each viscosity tested. Motilities of H. pylori from patients with duodenal ulcer or non-ulcer dyspepsia in methylcellulose solutions were not significantly different. H. pylori had poor motility in biopsied mucus, but became highly motile when biopsied mucus was diluted with saline. CONCLUSIONS: The viscosity-motility profiles of H. pylori in methylcellulose and the motilities of H. pylori in biopsied mucus suggest (1) that H. pylori may have poor motility in mucus at the epithelial surface, but high motility at the luminal surface of the mucus layer, and (2) that the increased mucus viscosity and decreased mucin size in patients with gastroduodenal disease act in combination to decrease H. pylori motility in vivo.

Clusters of new tuberculosis cases in North-west London: a survey from three hospitals based on IS6110 RFLP typing.

OBJECTIVES: The relative contributions of reactivation of latent infection and clusters of new infections to the overall incidence of tuberculosis in the U.K. is unknown. A study was carried out in North-West London to determine the feasibility of IS6110 RFLP strain typing as a tool to investigate the relative contributions of these two sources. METHODS: All available isolates of M. tuberculosis from specimens collected over a calendar year at three participating hospitals were typed by RFLP using an IS6110 probe. Isolates exhibiting a single band pattern were subject to further typing using an oligonucleotide direct repeat probe. Demographic and clinical information on cases was obtained from the National Survey of Tuberculosis Notifications in England and Wales and further information sought on clustered cases as identified by RFLP typing. RESULTS: Twenty-seven (23%) of the 118 cases had shared IS6110 RFLP patterns. Strains from nine cases had single band patterns, but these were all distinguishable from each other when subjected to further typing by direct repeat probe. The remaining 18 cases belonged to eight clusters. Epidemiological links were established between all the patients in each cluster. The likelihood of being in a cluster was increased in cases with pulmonary smear-positive disease. It was lower in cases of Indian Sub-continent ethnic origin. For 10 of the 18 clustered cases epidemiological links had not been established by conventional contact tracing. CONCLUSIONS: Investigation of the relative contributions of reactivation of latent infection and new infection is feasible in a UJK population, using IS6110 RFLP typing of M. tuberculosis isolates and epidemiological enquiries. This study in London identified clustered, presumably new cases, the majority of whom had not been linked epidemiologically. Comprehensive IS6110 RFLP typing of UK isolates would probably identify many clusters of incident tubercular infection.

Tuberculosis in HIV seropositive individuals--a retrospective analysis.

A retrospective analysis of all culture-positive cases of Mycobacterium tuberculosis infection in HIV positive individuals, over a 5 year period, revealed 18 cases, drawn from a population of approximately 1500. The prevalence of culture proven M. tuberculosis over the 5 year period was therefore 1.2% and was strongly associated with either a concomitant, or a subsequent, AIDS diagnosis. Sixty-one per cent had pulmonary tuberculosis, 17% had both extra-pulmonary and pulmonary infection and 22% had extra-pulmonary infection alone. Although a wide range of radiological abnormalities was seen, segmental consolidation was the commonest, occurring in 57% of cases. Only 55% of the specimens were positive on initial stains for M. tuberculosis, with a mean duration of 4 weeks to become culture positive, emphasizing that early diagnosis rests on clinical suspicion.

Analysis of infection in a burn ward.

One hundred and seventy-two burn wound swabs obtained from 90 patients admitted to the Aljila Hospital Burn Unit, Benghazi over a 3-month period were processed to determine the microbial flora colonizing burns and their resistance patterns to selected locally available topical and systemic agents. Approximately 84.9 per cent of the swab specimens yielded growth of 11 bacterial species and Candida spp.; of these, Ps. aeruginosa, Staph. aureus and Klebsiella spp. predominated in order of prevalence, followed by Enterobacteria. Polymyxin (100 per cent sensitive), amicacin (90.9 per cent sensitive) and carbenicillin (66.7 per cent sensitive) were the most effective of 10 selected antibiotics tested against the 60 pseudomonas isolates. In studies in vitro using six topical agents, Ps. aeruginosa strains were most sensitive, in decreasing order, to mafenide acetate, silver sulphadiazine, acetic acid, silver nitrate and Eusol. Seventy-eight per cent of Staph. aureus isolates were resistant to methicillin and erythromycin and 93 per cent to tetracycline.

Campylobacter pyloridis in the upper gastrointestinal tract: a Brazilian study.

The successful isolation of C. pyloridis from human gastric mucosa has renewed interest in these bacteria and their role as a causative agent for gastritis, and possible causal relationship between chronic gastritis and peptic ulceration. To determine the incidence of C. pyloridis in gastric biopsies we studied 51 consecutive Brazilian patients with a wide range of alimentary disorders presenting for endoscopy. At least three biopsies were taken from each site: antrum, any ulcer or cancer. Microbiological and histological studies were performed to identify the bacteria. The organism was found in 40/51 (78%) of patients. These was a close correlation between culture (100%), Gram (90%) and Gimenez staining (80%) in identifying the bacteria. All C. pyloridis positive patients had histological evidence of antral chronic gastritis (active or quiescent) even if the endoscopic appearance looked normal. All peptic ulcer patients (n = 17) showed C. pyloridis in the antrum. In the duodenum the bacteria were mainly seen in gastric type of mucosa. Our findings support the hypothesis that C. pyloridis is etiologically related to gastritis and possibly peptic ulceration.