Characteristics of Helicobacter pylori strains isolated from patients withdifferent gastric diseases

The pathogenesis of chronic gastritis, gastric ulcer, duodenal ulcer, gastr ic cancer, and remnant gastritis is considered to be related to infection b y Helicobacter pylori. The purpose of this study was to investigate the cha racteristics of H. pylori strains isolated from patients with various gastr ic diseases. Fifty strains of H. pylori were clinically isolated at Keio Un iversity Hospital and were assessed for (i) vacuolating cytotoxin (VT) prod uction, by cytotoxic assay using rabbit kidney (RK) 13 cells; (ii) the expr ession of cytotoxin associated gene (cagA), by polymerase chain reaction; a nd (iii) motility on a semi-solid plate. Positivity for VT production by H. pylori strains isolated from patients with chronic gastritis, gastric ulce r, duodenal ulcer, gastric cancer, and remnant gastritis, was 100%, 89%, 92 %, 100%, and 60%, respectively. There was no significant difference in the incidence of positivity for cagA among the strains isolated from different gastric diseases. Swarming distances, which indicate motility of PI. pylori strains, were 12.7, 13.2, 12.8, 16.6 and 9.2mm in strains from chronic gas tritis, gastric ulcer, duodenal ulcer, gastric cancer, and remnant gastriti s, respectively, with H. pylori isolated from remnant gastritis showing sig nificantly less motility than H. pylori isolates from other diseases. There were no significant differences in VT production and cagA positivity among the H. pylori strains.