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Helicobacter pylori Infection

(H. pylori Infection)

By Michael C. DiMarino, MD, Division of Gastroenterology and Hepatology, Department of Medicine, Thomas Jefferson University

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Helicobacter pylori (H. pylori) infection is a bacterial infection that causes stomach inflammation (gastritis), peptic ulcer disease, and certain types of stomach cancer.

  • The infection is caused by a type of bacteria called Helicobacter pylori (H. pylori).

  • When symptoms of H. pylori infection do occur, they include indigestion and pain or discomfort in the upper abdomen.

  • Doctors often base the diagnosis on the results of a breath test and an examination of the stomach using a flexible viewing tube (upper endoscopy).

  • Treatment is with antibiotics.

Infection with Helicobacter pylori,a type of bacteria, is the most common cause of gastritis and peptic ulcer disease worldwide. Infection is very common and increases with age. By age 60, about 50% of people are infected. Infection is most common among blacks, Hispanics, and Asians.

H. pylori is found in stool, saliva, and plaque on the teeth. H. pylori can be transmitted from person to person, especially if people who have the bacteria do not thoroughly wash their hands after a bowel movement. Infection also can occur if people touch their mouth after touching an object (such as a towel) contaminated by infected stool. Because people may also spread the bacteria through kissing or other close contact, infections tend to cluster in families and among people who live in nursing homes and other supervised facilities.

H. pylori bacteria grow in the protective mucus layer of the stomach lining, where they are less exposed to the highly acidic juices produced by the stomach. Additionally, H. pylori produce ammonia, which helps protect it from stomach acid and enables it to disrupt and penetrate the mucus layer. Virtually all people who have H. pylori infection have gastritis, which may affect the entire stomach or only the lower part (antrum). Infection can sometimes lead to erosive gastritis and perhaps even a stomach (gastric) ulcer. H. pylori contributes to ulcer formation by increasing acid production, interfering with the stomach's normal defenses against stomach acid, and producing toxins.


Most people with gastritis resulting from H. pylori infection do not develop symptoms, but people who do develop symptoms have those typical of gastritis, including indigestion and pain or discomfort in the upper abdomen.

Ulcers caused by H. pylori infection cause symptoms similar to ulcers caused by other disorders, including pain in the upper abdomen.


  • Tests of blood, breath, or stool

  • Sometimes upper endoscopy

H. pylori can be detected with tests that use blood, breath, or stool samples. However, because blood tests can remain positive for up to 3 years after the H. pylori infection has been eliminated, the breath test is often used to confirm treatment success.

Sometimes doctors use a flexible viewing tube (endoscope) to do an upper endoscopy to obtain a sample of the stomach lining for review under a microscope (biopsy).


The likelihood that a peptic ulcer caused by H. pylori infection will recur during the course of 1 year is greater than 50% in people who have not been treated with antibiotics. This percentage decreases to less than 10% in people who have been treated with antibiotics. In addition, treatment of H. pylori infection may heal ulcers that have resisted previous treatment.

Long-term infection with H. pylori increases the risk of stomach cancer.


  • Antibiotics and a proton pump inhibitor

H. pylori infection must be treated with antibiotics. The most popular treatment for H. pylori infection includes a proton pump inhibitor (see Table: Drugs Used to Treat Peptic Ulcer Disease) to reduce acid production combined with two antibiotics, such as amoxicillin and clarithromycin given twice daily for 14 days.

The combination of bismuth subsalicylate (a drug similar to sucralfate), tetracycline (an antibiotic), metronidazole (an antibiotic), and a proton pump inhibitor is another popular option. However, this treatment requires people to take a total of four drugs up to 4 times a day for 14 days. People who have duodenal or gastric ulcers take proton pump inhibitors for at least 4 weeks.

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