What Is H. Pylori?

By jolene

Reviewed: Dr. Mera

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Helicobacter pylori (H. pylori) was previously known as Campylobacter pylori. It is a Gram negative bacteria (according to a method of staining used to classify bacteria) that is usually found in the stomach. It is a ubiquitous organism that can be found in as many as 50% of the global population. First identified by Australian doctors Robin Warren and Barry Marshall in 1982, they observed that it was present in individuals with gastric ulcers and chronic gastritis.

H. pylori has been linked to the development of gastric ulcers, duodenal ulcers, and stomach cancer. However, as many as 80% of infected individuals are asymptomatic. The infection is especially common in developing countries. Due to the helical shape of the bacteria, it is thought to have evolved into this shape to enable it to penetrate the mucoid lining of the stomach. The commonest route of infection would be oral to oral or fecal to oral contact.

1. Pathophysiology

Since the most common route of infection is mouth to mouth or stool to mouth contact, a primary role in transmission is seen among parents and siblings. In a susceptible individual, the infection leads to chronic active gastritis that can result in duodenal and gastric ulcers and cancer. H. pylori causes striking infiltration of the gastric lining or epithelium and the underlying lamina propria by cells that belong to the immune system (i.e. neutrophils, macrophages, lymphocytes). The bacteria use its flagella (whip-like structure that acts a propeller) to burrow into the mucus lining as it is less acidic. The infection also results in the production of toxins that harm cells (cytotoxins) and can cause inflammation. This means colonization of the stomach by the bacteria can result in inflammation and chronic gastritis.