Infections with organisms of the genus HELICOBACTER, particularly, in humans, HELICOBACTER PYLORI. The clinical manifestations are focused in the stomach, usually the gastric mucosa and antrum, and the upper duodenum. This infection plays a major role in the pathogenesis of type B gastritis and peptic ulcer disease. The disease is MONDO_0006781 (Helicobacter pylori infectious disease). Also known as: Helicobacter pylori caused disease or disorder, Helicobacter pylori disease or disorder.