The nature of Helicobacter pylori.

Helicobacter pylori is an important pathogen in humans, causing chronic gastritis and playing a major role in the development of peptic ulcers and gastric cancer. The organism is highly adapted to the human stomach, largely due to its motility and ability to produce large amounts of urease. It binds specifically to the gastric mucosa via adhesion pedestals; colonization of the duodenum only occurs in the presence of gastric metaplasia. Infection with H. pylori leads to gastritis, but the majority of infected patients are asymptomatic, and it is thought that the ability of H. pylori to cause more severe disease may be related to the presence of the cagA gene. With improvements in public health and living conditions, the prevalence of H. pylori infection in developed countries is decreasing, and this is associated with a decline in the incidence of peptic ulcer and gastric cancer.