NC_010698:870312 Helicobacter pylori Shi470, complete genome
Host Lineage: Helicobacter pylori; Helicobacter; Helicobacteraceae; Campylobacterales; Proteobacteria; Bacteria
General Information: Helicobacter pylori Shi470 is a clinical isolate from gastric antrum from Amerindian resident of remote Amazonian village of Shimaa, Peru. Helicobacter pylori chronically infects stomachs of billions of people worldwide, is implicated in peptic ulcer disease and gastric cancer, and is very diverse genetically. This genus consists of organisms that colonize the mucosal layer of the gastrointestinal tract or are found enterohepatically (in the liver). It was only recently discovered (1983) by two Australians (Warren and Marshall) that this organism was associated with peptic ulcers. It is one of the most common chronic infectious organisms, and is found in half the world's population. This organism attacks the gastric epithilial surface, resulting in chronic gastritis, and can cause more severe diseases including those that lead to gastric carcinomas and lymphomas, peptic ulcers, and severe diarrhea. It is an extracellular pathogen that persists in the gastric environment, which has a very low pH, by production of the urease enzyme, which converts urea to ammonia and carbon dioxide, a process which can counteract the acidic environment by production of a base. The toxins include cytolethal distending toxin, vacuolating cytotoxin (VacA) that induces host epithelial cell apopoptosis (cell death), and the cytotoxin associated antigen (CagA) which results in alteration to the host cell signalling pathways. The CagA protein is translocated into host cells by a type IV secretion system encoded by the cag pathogenicity island.