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Helicobacter pylori

Helicobacter pylori (H. pylori) is a bacterium that grows in the inner lining of the stomach (mucosa). H. pylori causes a common stomach infection. It is also an important cause of stomach cancer and some types of lymphoma of the stomach.

H. pylori infection is common. Generally, rates of H. pylori infection are higher in developing countries than in developed countries. Some Canadians have much higher infection rates, including First Nations communities and immigrants from countries such as Japan, Korea and China, where there is a high incidence of H. pylori infection.

Most people are infected with H. pylori during childhood. H. pylori infection usually lasts for life unless it is treated. Most people infected with H. pylori don’t have any symptoms or health problems related to the bacterium. Some people with chronic infection develop symptoms, such as stomach pain, nausea or vomiting. H. pylori can cause chronic inflammation of the inner lining of the stomach (gastritis) and stomach ulcers. About 10%–15% of people with H. pylori infection develop peptic ulcer disease (sores or ulcers in the lining of the stomach or duodenum of the small intestine).

  • Exposure

    It is not known for sure how H. pylori spreads, but it is thought to spread through contaminated food and water. People may pick up the bacterium from food that has not been washed well or cooked properly. They may also get it from drinking water from an unclean source. It may also be passed from person to person through direct contact with the saliva or stool of an infected person.

    Risk factors associated with H. pylori infection include:

    • crowded living conditions
    • poor sanitation
    • increased number of siblings (especially when sharing beds)
    • lower socio-economic status
  • H. pylori and cancer

    H. pylori infection causes certain cancers and other illnesses.

    Stomach cancer

    H. pylori infection is a major cause of stomach (gastric) cancer. H. pylori causes chronic gastritis, which is thought to be the first step in the development of stomach cancer. H. pylori infection is a necessary, but not the only, cause of adenocarcinoma, which is the most common type of cancer that occurs in the non-cardia regions of the stomach. The cardia region of the stomach is the small, upper part of the stomach near the esophagus. The non-cardia regions are the remaining parts of the stomach. Adenocarcinoma accounts for up to 95% of all stomach cancers.

    Less than 3% of people with H. pylori infection develop stomach cancer.

    MALT lymphoma

    H. pylori infection is associated with a higher risk of MALT lymphoma of the stomach. This is a type of non-Hodgkin lymphoma (NHL). MALT lymphoma of the stomach accounts for less than 2% of all stomach cancers. Nearly all MALT lymphomas of the stomach are related to H. pylori infection. People infected with H. pylori have a low risk of developing MALT lymphoma (less than 1%).

    Other illnesses

    H. pylori has been linked with other cancers, such as pancreatic and colorectal cancer, but there is not enough evidence to say for sure whether or not it is a risk factor for these cancers.

    There is some evidence that H. pylori may also help prevent some childhood diseases, such as asthma. It may also prevent adult diseases, such as esophageal adenocarcinoma. More research is needed to confirm these findings.

  • How to test for H. pylori infection

    Testing for H. pylori can be done using a variety of tools.

     Test  Description
    breath test  The urea breath test (UBT) is a non-invasive tool used to detect H. pylori infection. It is very good at detecting H. pylori. In Canada, UBT is the preferred non-invasive test for H. plylori infection.
     blood test  A blood test (serology) detects specific antibodies to H. pylori, which the immune system develops in response to the bacterium. The blood test shows if someone has been exposed to H. pylori. A positive test indicates an infection is present or the person had an infection in the past.
     stool test Some tests detect H. pylori  antigens in stool. Although stool antigen testing is accurate and easy to do, it is not as good at finding H. pylori as the other tests.
     endoscopy  In certain situations, an upper GI endoscopy (gastroscopy) is done to diagnose H. pylori infection. During endoscopy, the doctor takes biopsies of the stomach lining. These samples are used to confirm a diagnosis of H. pylori, detect complications associated with H. pylori infection (such as suspected peptic ulcer) or rule out other health problems.
  • Who should be tested for H. pylori infection

    The Canadian Helicobacter Study Group (CHSG) developed guidelines for the care of Canadians with H. pylori infection, including children and adults. Routine testing for H. pylori is not recommended if an adult or child does not have any symptoms (asymptomatic) and does not have a past history of peptic ulcer disease. Most experts agree that the current evidence does not support widespread testing for and treating H. pylori infection.

    However, there is evidence to support testing and treating H. pylori in certain high-risk individuals.

    • Testing for H. pylori infection is reasonable in people with symptoms of dyspepsia (such as upper abdominal pain or discomfort), a gastric or duodenal ulcer or a past history of ulcers.
    • People who come from or have ancestors from a region where there is a high incidence of H. pylori infection and a higher incidence of stomach cancer should be tested and treated for this bacterium.
    • People with a strong family history of stomach cancer in first-degree relatives (parents, brothers, sisters or children) should be tested and treated for H. pylori infection.
      • First-degree relatives may have a 2–3 times greater risk of developing gastric cancer.
    • People with MALT lymphoma should be tested for H. pylori and treated if the test result is positive.
    • People having surgery (resection) for early stomach cancer should be tested for H. pylori infection.
    • People starting long-term treatment with non-steroidal anti-inflammatory drugs (NSAIDs) or acetylsalicylic acid (aspirin, ASA) should be tested for H. pylori infection and treated if the test result is positive.

    Japan, Korea and Matsu Island in Taiwan continue to have a high incidence of H. pylori infection and gastric cancer. These countries have population-based screening programs to find and treat H. pylori infection.

  • Treating H. pylori infection

    People infected with H. pylori are usually given a course of triple therapy that lasts 7–14 days.

    • Triple therapy includes a proton pump inhibitor (PPI) and 2 antibiotics.
      • The PPI medication lowers stomach acid production, which allows the tissues damaged by the infection to heal.
      • Antibiotics help make sure the treatment works.
    • Quadruple therapy is another treatment. It consists of a PPI, 2 antibiotics and bismuth subsalicylate.
      • Bismuth subsalicylate is a drug used for upset stomach. It helps slow the growth of bacteria.

    H. pylori infection usually responds to treatment. Treatment cures H. pylori infection in 80%–90% of people.

    • Most low-grade MALT lymphomas linked to H. pylori infection can be cured by getting rid of H. pylori. Treating H. pylori is strongly associated with remission of low-grade MALT lymphoma.

    There is not enough evidence to support treating children for H. pylori infection to prevent stomach cancer later in life.

  • Reducing your risk

    The source of H. pylori is not yet known, so there aren’t specific recommendations for avoiding infection.

    In general, it is always wise for you to:

    • Wash your hands thoroughly.
    • Eat food that has been properly prepared.
    • Drink water from a safe, clean source.


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