Outcome of patients with inconsistent results from 13C-urea breath test and bacterial culture at the time of assessment of Helicobacter pylori eradication therapy in Japan.

BACKGROUND/AIMS: At the assessment of eradication therapy of Helicobacter pylori, the results of 13C-urea breath test and other methods such as bacterial culture are occasionally inconsistent. In this study, we examined the outcomes of inconsistent results. METHODOLOGY: Four hundred and four patients with peptic ulcer who were H. pylori-positive and who had completed eradication therapy were studied. Bacterial culture, rapid urease tests and 13C-urea breath test were performed between one and three months after the end of the therapy. The cut-off value for the 13C-urea breath test used originally in this study was 2.5 per mil. We investigated the outcome of inconsistent results by following up the patients every 6 to 12 months. RESULTS: At the initial assessment of eradication therapy, we observed inconsistent results with bacterial culture and 13C-urea breath test in 43 of 404 patients. Most of them (40 of 43) were culture-negative but urea breath test-positive, and the majority became negative for both tests. Based on the follow-up results, the optimum value for 13C-urea breath test at the assessment of eradication therapy was found to be 3.5 per mil. CONCLUSIONS: We found that outcomes of inconsistent results were variable, indicating the importance of the follow-up of patients after eradication therapy of H. pylori.

H. pylori decreases gastric mucin synthesis via inhibition of galactosyltransferase.

BACKGROUND/AIMS: Alterations of gastric mucin have been postulated as important pathogenic properties of Helicobacter pylori. In this study, we investigated gastric mucin synthesis in H. pylori-infected gastric mucosa by measuring UDP-galactosyltransferase activity, a key enzyme for the synthesis of mucin, and the amount of intracellular mucin in the gastric mucosa. METHODOLOGY: Gastric biopsy specimens were obtained from thirty-seven patients (20 H. pylori-positive and 17 H. pylori-negative). UDP-galactosyltransferase activity of the biopsy specimens was measured by an assay system we had developed, using a peanut agglutinin lectin. The amount of intracellular mucin in the gastric epithelial cells was analyzed by measuring the cells' periodic acid-Schiff-alcian blue staining-positive substances. RESULTS: UDP-galactosyltransferase activities in the antral mucosa, but not in the body mucosa, of H. pylori-positive patients were significantly lower than those of H. pylori-negative patients (p < 0.05). The amount of intracellular mucin in antral epithelial cells of H. pylori-positive patients was significantly lower than that of H. pylori-negative patients (p < 0.01). CONCLUSIONS: These findings suggest that H. pylori infection decreases gastric mucin synthesis via inhibition of UDP-galactosyltransferase. This effect may impair the gastric mucosal barrier and contribute to the mucosal injury induced by H. pylori infection.

Reinfection rate following effective therapy against Helicobacter pylori infection in Japan.

BACKGROUND AND AIM: In developed countries, reinfection of Helicobacter pylori (H. pylori) after eradication of the bacterium is unusual, while the reinfection rate in developing countries is variable. In this study, we determined the reinfection rate after successful H. pylori eradication in Japan, a country with a high prevalence of H. pylori infection. METHODS: After successful eradication, 377 patients were followed up by endoscopy and urea breath test annually. In reinfected patients, H. pylori strains isolated initially and after reinfection were compared by using random amplification of polymorphic DNA fingerprinting. RESULTS: H. pylori became positive in four of 337 patients (1.2) 1 year after eradication and in two of 133 patients (1.5) 2 years after eradication. One patient experienced an ulcer relapse 2 years after eradication therapy. Random amplification of polymorphic DNA fingerprinting of the isolated strains from four of the six patients showed two had identical strains (at 1 year) while the other two had different strains (one at 1 year and one at 2 years). When infection in the two patients reinfected with identical strains is considered a recrudescence, the true reinfection rate is < 0.8 per patient year. CONCLUSIONS: The reinfection rate after eradication of H. pylori is low in Japan despite the country's high prevalence of H. pylori infection.