Helicobacter Pylori Bacteria

Topic Overview

Helicobacter pylori is a type of bacteria that is a major cause of stomach (gastric) and upper small intestine (duodenal) ulcers. Infection with H. pylori may also increase the risk of stomach cancer.

H. pylori bacteria can cause ulcers by growing in the lining of the stomach, producing inflammation and causing the stomach and intestinal lining to be more easily damaged by stomach acid. But most people infected with H. pylori do not develop ulcers. An additional factor—one that cannot always be identified—may be needed to cause an ulcer to form. Such factors may include:

• The use of certain medicines, such as aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs).
• Excessive alcohol use.
• Other illnesses.

H. pylori bacteria can be eliminated by taking certain antibiotics that are specifically directed at this bacteria.

People who have had a peptic ulcer and are infected with H. pylori need treatment to cure the infection to lower their risk of getting another peptic ulcer. Treatment with a combination of medicines is highly successful at curing an H. pylori infection.^{footnote 1} Sometimes H. pylori bacteria are resistant to certain antibiotics, which can keep the medicine from killing the bacteria.

For some people who have taken medicine to treat the H. pylori infection, a follow-up test may be needed to make sure the infection is cured.