H. Pylori

Helicobacter pylori is a gram-negative, urease-producing bacterium that lives within the gastric mucus layer. Urease hydrolyses urea into ammonia, buffering acid immediately around the organism. That local protection permits persistent colonisation despite the stomach’s otherwise hostile environment; the same urease activity is the basis of the urea breath test. Persistent infection produces chronic active gastritis. Over time, inflammation may progress to peptic ulcer disease, gastric atrophy, intestinal metaplasia, gastric adenocarcinoma, or gastric MALT lymphoma. The International Agency for Research on Cancer classifies H. pylori as a Group 1 carcinogen. It is the principal modifiable cause of non-cardia gastric adenocarcinoma and gastric MALT lymphoma, so treatment is not simply an attempt to relieve dyspepsia. Eradication is indicated for active or previous peptic ulcer disease, gastric MALT lymphoma, gastric atrophy or intestinal metaplasia, and a personal or family history of gastric cancer. It is also indicated in uninvestigated dyspepsia without alarm features, unexplained iron-deficiency anaemia, and immune thrombocytopenia. Testing may be considered before long-term NSAID or ASA therapy. The 2024 American College of Gastroenterology guideline also recommends testing adult household contacts of...