Helicobacter pylori in adults
About half of the world’s population is infected with a bacterium called Helicobacter pylori (H. pylori). It is the leading cause of stomach ulcers and also increases the risk of certain cancers. The infection is more common in lower-income countries and can be treated with antibiotics and other drugs.
What is H. pylori?
H. pylori is a spiral-shaped bacterium that burrows into the lining of the stomach, causing damage and inflammation. It is one of the most common human infections, and affects about 4.4 billion people worldwide. Global health agencies are working to eradicate H. pylori because it contributes to the development of several types of cancer. Even patients who have no symptoms of the infection should be treated, to reduce the risk of ulcers and cancer, and to prevent the spread of the bacterium to others.
What are the symptoms of H. pylori infection?
Many people have no indications that they are infected by the bacterium, however, some people experience the following symptoms:
- Indigestion or an ache in the abdomen
- Abdominal pain that is worse in the mornings or when the stomach is empty
- Reduced appetite
- Frequent burping
- Unintentional weight loss
Rarely, more serious symptoms can occur, which require immediate medical care:
- Severe or continuous abdominal pain
- Difficulty swallowing
- Stools that are blood or tarry
- Vomit that is black, bloody or looks like coffee grounds
Who is at risk of H. pylori infection?
People typically become infected with H. pylori as children when they are exposed through close contact with family members. Contaminated food or water can also transmit the organism. People living in crowded conditions without access to adequate sanitation have the greatest risk. Worldwide, the highest rates of H. pylori infection occur in Africa, followed by Latin America and Asia.
How to diagnose an H. pylori infection
- Stool test: This diagnostic test detects foreign proteins associated with pylori in the stool.
- Breath test: After a person swallows a pill, liquid or pudding that contains a specific chemical broken down by pylori, the breath is analysed to see if it contains the breakdown products.
- Blood test: This test detects antibodies to the bacterium circulating in the bloodstream, but is less reliable than the breath and stool tests.
- Scope test: In some cases, a doctor may perform an upper endoscopy by inserting a camera at the end of a flexible tube down the throat to examine the stomach and the upper part of the small intestine. During the procedure, the doctor can take a biopsy sample and rule out other digestive problems.
The link between H. pylori and cancer
About 1 to 3% of people infected with H. pylori will develop stomach cancer and the bacterium is estimated to be the cause of 89% of all stomach cancer cases worldwide. Research suggests that H. pylori also increases the risk of gastric lymphoma and bowel cancer. People with H. pylori tend to have lower rates of oesophageal cancer, but the reason why is not yet clear.
Heath experts recommend that all individuals who test positive for H. pylori seek treatment to reduce their cancer risk. In countries where cases of H. pylori infections have dropped, rates of stomach cancer have also decreased.
How to treat H. pylori infection
Traditionally, a person with a positive diagnostic test for H. pylori will be prescribed two antibiotics and a drug to reduce stomach acid, which allows the lining of the stomach to heal. The prescribed acid-suppressing drug may be a proton-pump inhibitor, a histamine blocker or bismuth salts, which is a common upset stomach remedy. Patients will take the drugs for seven to 14 days. Doctors recommend testing for H. pylori again after four weeks post-treatment. If the infection persists, the patient may repeat the treatment with different antibiotics.
The best treatment for eliminating H. pylori will vary by region because the bacterium is evolving resistance to the most commonly prescribed antibiotics. In most parts of the world, more than 15% of H. pylori infections cannot be treated by the first-line antibiotics, clarithromycin, metronidazole and levofloxacin. Depending on the local rates of resistance, doctors may prescribe higher doses, longer courses or a series of different antibiotics.
Antibiotic treatments frequently cause short-term but unpleasant side effects, including diarrhoea, nausea, vomiting, bloating and abdominal pain. As a result, some patients stop taking the drugs too early, causing the treatment to fail and also driving the development of antibiotic-resistant strains of the bacterium. Several recent studies have shown that certain probiotics can lessen the severity of diarrhoea resulting from antibiotic use, which may help people to finish the complete antibiotic treatment.