HELICOBACTER-PYLORI

Helicobacter pylori is a gram-negative bacterium which causes chronic gastritis and plays important roles in peptic ulcer disease, gastric c arcinoma, and gastric lymphoma. H. pylori has been found in the stomac hs of humans in all parts of the world. In developing countries, 70 to 90% of the population carries H. pylori. In developed countries, the prevalence of infection is lower. There appears to be no substantial r eservoir of H. pylori aside from the human stomach. Transmission can o ccur by iatrogenic, fecal-oral, and oral-oral routes. H. pylori is abl e to colonize and persist in a unique biological niche within the gast ric lumen. All fresh isolates of H. pylori express significant urease activity, which appears essential to the survival and pathogenesis of the bacterium. A variety of tests to diagnose H. pylori infection are now available. Histological examination of gastric tissue, culture, ra pid urease testing, DNA probes, and PCR analysis, when used to test ga stric tissue, all require endoscopy. In contrast, breath tests, serolo gy, gastric juice PCR, and urinary excretion of [N-15]ammonia are noni nvasive tests that do not require endoscopy. In this review, we highli ght advances in the detection of the presence of the organism and meth ods of differentiating among types of H. pylori, and we provide a back ground for appropriate chemotherapy of the infection.