THE IMPORTANCE OF LOCAL ACID PRODUCTION IN THE DISTRIBUTION OF HELICOBACTER-FELIS IN THE MOUSE STOMACH

Background/Aims: Helicobacter felis colonizes the gastric mucosa of ro dents. Preliminary studies showed differences in the distribution of t he organism in different parts of the stomach that seemed related to t he secretory capacity of the mucosa. The aim of this study was to dete rmine the localization of H. felis in the mouse stomach and to investi gate the influence of acid-suppressive agents. Methods: Specific-patho gen-free BALB/c mice were infected with H. felis. Colonization was ass essed in longitudinal sections of gastric tissue from animals untreate d or treated with omeprazole or ranitidine. Results: In untreated H. f elis-infected animals, the preferred ecological niche was the antrum a nd cardia equivalent. The density of colonization correlated with the number of parietal cells per gland. Partial acid suppression with rani tidine produced a slight increase in the colonization of the body but was restricted to the upper portions of the gastric gland. Omeprazole treatment produced a greater colonization of the body with bacteria tr aversing the entire gland. Some reduction in antral colonization occur red. Conclusions: These results are consistent with the hypothesis tha t local acid output is a crucial determinant in the distribution of He licobacter species in the stomach. Differences in local acid output ma y explain the different patterns of Helicobacter pylori-induced gastri c pathology.