ABSTRACT
OBJECTIVES: This study was carried out to survey the prevalence of Helicobacter pylori infection and the incidence of vacuolating toxin producing H. pylori. A further aim of this study was to evaluate the quantitative assay for cell vacuolation on the basis of the rapid uptake of neutral red dye by vaculoes of the cells. METHODS: We studied the gastric biopsy specimens of patients with 154 cases of gastritis, 74 cases of gastric ulcer, and 167 cases of gastric cancer and in 44 cases of healthy persons. One of the biopsy specimen was placed into a CLOtest plate for rapid urease test and the other one of the biopsy spcimen was inoculated on Brain Heart Infusion blood agar for culture. The culture supernatant of isolated H. pylori was serially diluted with BHI broth. After 24 hour incubation of cultured RK-13 cells treated with the culture supernatant of H. pylori, cytoplasmic vacuolation of the cells were observed microscopically. RESULTS: The positivity of urease test and the rate of isolation of H. pylori from urease positive gastric biopsy materials were 34.1% and 93.3% in healthy person, 55.8% and 70.9% in gastritis, 60.8% and 71.1% in gastric ulcer, and 56.3% and 96.8% in gastric cancer. The isolation rate of H. pylori from patients between 20 and 39 years old was 16.8%, for patients between 40 and 59 years old it was 51.9%, and for patients above 60 years old it was 31.2%. The isolation rate of the vacuolating toxin producing H. pylori from gastric biopsy specimens was 66.7% in a healthy person, 76.6% in gastritis, 79.4% in gastric ulcer, and 80% in gastric cancer. CONCLUSIONS: The isolation rate of H. pylori from the patients with gastric diseases is higher than the rate of H. pylori from healthy persons, but the isolation rate of the vacuolating toxin producing H. pylori is not different between the patients with gastric diseases and healthy persons. The titers of vacuolating toxin produced by some H. pylori isolated from the patients with gastric diseases are higher than those from healthy persons.