The University of Arizona

H. Pylori Mode of Action

H. Pylori Mode of Action

H. pylori infects the stomach or the first part of the small intestine (duodenum). H. pylori is able to “glue” itself to cell surfaces under stomach’s mucosal layer, thus protecting itself from immune reactions. It colonizes the stomach, induces inflammatory cytokines, and causes gastric inflammation. H. pylori’s survival in the acidic medium of the stomach depends on its ability to neutralize the acid through the production of urease which reacts with urea to form ammonia which is toxic to human cells. H. pylori’s flagella facilitate the passage of H. pylori from the acidic lumen into the mucus of the stomach.

The effect of H. pylori infection on acid production depends on the colonized area. If H. pylori colonize the central part of the stomach, the acid-producing cells are affected leading to low stomach acid. However, if colonization is near the junction of the stomach with the duodenum, H. pylori can affect the cells which control acid secretion leading to overproduction of hydrochloric acid and ulceration. Although stomach inflammation or gastritis always accompanies H. pylori infection, acid production is not affected in those people who do not experience any of the complications.

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