Helicobacter pylori
and Gastric Ulcers
Helicobacter pylori is a gram-negative, highly motile, spiral shaped bacterium related to Campylobacter. The organism is 2.5–3.5 m long and 0.5–1.0 m in diameter and has one to six polar flagella at one end.
H. pylori is a pathogen associated with gastritis, ulcers, and gastric cancers.
This organism colonizes the non-acid-secreting mucosa of the stomach and the upper intestinal tract, including the duodenum.
Up to 80% of gastric ulcer patients have concomitant H. pylori infections, and up to 50% of asymptomatic adults in developing
countries are chronically infected. Person-to-person contact and ingestion of contaminated food or water are the probable transmission methods for H. pylori. Although there is no known nonhuman reservoir of H. pylori, the organism has occasionally been
recovered from cats kept as household pets, indicating that it can be spread to or from animals in close contact with humans.
Infection occurs in high incidence within families, and the overall prevalence in the population increases with age. These factors
suggest host-to-host transmission. However, infections with H. pylori sometimes also occur in epidemic clusters, suggesting
transmission from common sources such as food or water.
Clinical signs of H. pylori infection include belching and stomach (epigastric) pain