H. pylori

n. Helicobacter pylori, spiral-shaped type of bacteria causing ulcers and inflammation in the stomach or small intestine

Helicobacter pylori is a helical shaped Gram-negative bacterium that infects various areas of the stomach and duodenum. Many cases of peptic ulcers, gastritis, duodenitis, and perhaps some cancer are caused by H. pylori infection. However, many who are infected do not show any symptoms of disease. Helicobacter spp. are the only known microorganisms that can thrive in the highly acidic environment of the stomach. Its helical shape (from which the genus name is derived) is thought to have evolved to penetrate and favor its motility in the mucus gel layer.
See more at Wikipedia.org...

Noun
1. the type species of genus Heliobacter; produces urease and is associated with several gastroduodenal diseases (including gastritis and gastric ulcers and duodenal ulcers and other peptic ulcers)
(synonym) Heliobacter pylori
(hypernym) bacteria species

Helicobacter pylori. Bacteria that cause inflammation and ulcers in the stomach.