<prompt> H. pylori true about -Gram ve spiral organismIt is a protozoaCauses chronic gastritis in adults due to re-infectionTreatment causes regression of gastric lymphoma  <response>: Ans. is d i.e., Treatment causes regression of gastric lymphoma Infection of the stomach by the bacterium helicobacter pylori induces the development of gastric MALT mucosa -associated lymphoid tissue lymphomas. This association is suppoed by evidence that patients treated with antibiotics to eradicate H. pylori have regression of their MALT lymphoma. About other options . H pylori is a gram negative not gram positive spiral bacillus. . It is a bacteria not protozoa. . H. pylori colonization induces chronic superficial gastritis. It is due to primary colonization, not reinfection. After eradication, reinfection rate causing chronic gastritis is less than .5 per year. . It causes mucosal damage of duodenum due to increased gastric acid secretion, which induces protective gastric metaplasia in the duodenum. The duodenum becomes inflammed and then ulcerated. 