Helicobacter Pylori

What is Helicobacter pylori?

Helicobacter pylori (H. pylori) is a bacterium that causes chronic inflammation of the inner lining of the stomach (gastritis) in humans. This bacterium also is the most common cause of ulcers worldwide. H. pylori infection is most likely acquired by ingesting contaminated food and water and through person to person contact. In the United States, 30% of the adult population is infected. (50% of infected persons are infected by the age of 60.) The infection is more common in crowded living conditions with poor sanitation. In countries with poor sanitation, 90% of the adult population can be infected. Infected individuals usually carry the infection indefinitely unless they are treated with medications to eradicate the bacterium. One out of every six patients with H. pylori infection will develop ulcers of the duodenum or stomach. H. pylori also is associated with stomach cancer and a rare type of lymphocytic tumor of the stomach called MALT lymphoma.

How is H. pylori infection diagnosed?

Accurate and simple tests for the detection of H. pylori infection are available. They include blood antibody tests, urea breath tests, stool antigen tests, and endoscopic biopsies.

Blood tests for the presence of antibodies to H. pylori can be performed easily and rapidly. However, blood antibodies can persist for years after complete eradication of H. pylori with antibiotics. Therefore, blood antibody tests may be good for diagnosing infection, but they are not good for determining if antibiotics have successfully eradicated the bacterium.

The urea breath test (UBT) is a safe, easy, and accurate test for the presence of H. pylori in the stomach. The breath test relies on the ability of H. pylori to break down the naturally occurring chemical, urea, into carbon dioxide which is absorbed from the stomach and eliminated from the body in the breath. Ten to 20 minutes after swallowing a capsule containing a minute amount of radioactive urea, a breath sample is collected and analyzed for radioactive carbon dioxide. The presence of radioactive carbon dioxide in the breath (a positive test) means that there is active infection. The test becomes negative (there is no radioactive carbon dioxide in the breath) shortly after eradication of the bacterium from the stomach with antibiotics. Despite the fact that individuals having the breath test are exposed to a minute amount of radioactivity, the breath test has been modified so that it also may be performed with urea that is not radioactive.

Endoscopy is an accurate test for diagnosing H. pylori as well as the inflammation and ulcers that it causes. For endoscopy, the doctor inserts a flexible viewing tube (endoscope) through the mouth, down the esophagus, and into the stomach and duodenum. During endoscopy, small tissue samples (biopsies) from the stomach lining can be removed. A biopsy specimen is placed on a special slide containing urea (e.g., CLO test slides). If the urea is broken down by H. pylori in the biopsy, there is a change in color around the biopsy on the slide. This means that there is an infection with H. pylori in the stomach.

The most recently-developed test for H. pylori is a test in which the presence of the bacterium can be diagnosed with a sample of stool. The test uses an antibody to H. pylori to determine if H. pylori is present in the stool. If it is, it means that H. pylori is infecting the stomach. Like the urea breath test, in addition to diagnosing infection with H. pylori, the stool test can be used to determine if eradication has been effective shortly after treatment.

Why treat H. pylori?

Chronic infection with H. pylori weakens the natural defenses of the lining of the stomach against the ulcerating action of acid. Medications that neutralize stomach acid (antacids), and medications that decrease the secretion of acid in the stomach (H2-blockers and proton pump inhibitors or PPIs) have been used effectively for many years to treat ulcers. H2-blockers, include ranitidine (Zantac), famotidine (Pepcid), cimetidine (Tagamet), and nizatidine (Axid). PPIs include omeprazole (Prilosec), lansoprazole (Prevacid), rabeprazole (Aciphex), pantoprazole (Protonix), and esomeprazole (Nexium). Antacids, H2-blockers and PPIs, however, do not eradicate H. pylori from the stomach, and ulcers frequently return promptly after these medications are discontinued. Hence, antacids, H2-blockers or PPIs have to be taken daily for many years to prevent the return of the ulcers and the complications of ulcers such as bleeding, perforation, and obstruction of the stomach. Eradication of H. pylori prevents the return of ulcers and ulcer complications even after the medications are stopped. Eradication of H. pylori also is important in the treatment of the rare condition known as MALT lymphoma of the stomach. Treatment of H. pylori to prevent stomach cancer is controversial and discussed later.

How is H. pylori treated?

H. pylori is difficult to eradicate from the stomach because it is capable of developing resistance to commonly used antibiotics. Therefore, two or more antibiotics usually are given together with a PPI and/or bismuth containing compounds to eradicate the bacterium. (Bismuth and PPIs have anti-H. pylori effects.) Examples of combinations of medications that are effective are:

• a PPI, amoxicillin (Amoxil) and clarithromycin (Biaxin)
• a PPI, metronidazole (Flagyl), tetracycline and bismuth subsalicylate

These combinations of medications can be expected to cure 70%-90% of infections. However, studies have shown that resistance of H. pylori (failure of antibiotics to eradicate the bacteria) to clarithromycin is common among patients who have prior exposure to clarithromycin or other chemically similar macrolide antibiotics (such as erythromycin). Similarly, H. pylori resistance to metronidazole is common among patients who have had prior exposure to metronidazole. In these patients, doctors have to find other combinations of antibiotics to treat the H. pylori. Antibiotic resistance is another reason why antibiotics should be used carefully and judiciously for the right reasons, and indiscriminate use of antibiotics for improper reasons should be discouraged.

Some doctors may want to confirm eradication of H. pylori after treatment with a urea breath test or a stool antigen test, particularly if there have been serious complications of the infection such as perforation or bleeding in the stomach or duodenum. Endoscopic biopsies to determine eradication of the bacteria are not necessary, and blood tests are not good for determining eradication since it takes many months for the antibodies to H. pylori to decrease. The best tests for determining eradication are the breath and stool tests discussed previously. Patients who fail to eradicate H. pylori with treatment are retreated, often with a different combination of medications.