Helicobacter pylori
Introduction
Helicobacter pylori (H. pylori) is a Gram-negative bacterium which is usually found in stomach and duodenum. It is the only bacteria that survives in the acidic environment of our stomach. H. pylori has protective layers around them and produces urease to convert urea from gastric juices into ammonia. Thus, the environment surrounding the bacterium is neutralized. H. pylori infection can induce chronic gastritis, gastric or duodenal ulcer and gastric cancer.
Transmission
Around 4.4 billion people are estimated to be infected by H. pylori worldwide while many regions in Asia including Hong Kong show an infection rate over 55%. No current research has indicated exact transmission mode of the bacterium. However, experts believe that H. pylori can spread via the following routes:
- Ingestion of contaminated food or contact. Also, since H. pylori may live in teeth plaque, mouth-to-mouth contact such as kissing can increase risk of infecting the bacterium.
- Higher risk in members of common living household such as family.
- Contact with body fluid or faeces of infected person
Symptoms
Most infection cases are asymptomatic. However, patients with acute gastritis experience stomach ache and nausea while those with chronic digestive problem may have indigestion, stomach ache, stomach bloating, belching, nausea, vomiting and darkened faeces.
Diagnosis
Several diagnostic techniques to confirm H. pylori infection:
- Campylobacter-like organism test (CLO test): The test can determine the infection of H. pylori by examining the gastric tissue biopsy which allows the doctor to find the bacterium in stomach.
- Serological test(H.P. antibodies): The test is to obtain the blood sample to examine the presence of H.P. antibodies in blood. The result, however, can still show positive even after the successful treatment and complete removal of H. pylori.
- Urea breath test: Patients need to swallow urea labelled with an uncommon isotope which helps detect the carbon dioxide produced from H. pylori in exhaled breath.
- H. pylori histology: Gastric biopsies can diagnose of H. pylori infection and associated lesions (eg. Atrophic gastritis, intestinal metaplasia, dysplasia, and MALT lymphoma). Biopsies for histology should be taken from both the antrum and body of the stomach, especially when looking for evidence of multifocal atrophic gastritis and/or intestinal metaplasia. The sensitivity and specificity of histology for diagnosis of H. pylori infection are 95 and 98 percent, respectively.
- Bacterial culture: Using bacterial culture can diagnose the H. pylori infection. And doctors use the antibody susceptibility testing to improve the chance of killing the bacterium.
Treatment
No instant treatment is needed for patients without symptoms present or comorbidity. However, patients should seek professional advice from doctors when noticing any of these signs or symptoms:
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Digestive ulcer
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Indigestion
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Gastric cancer
The PPI-based triple therapy with two to three antibiotics is used for H. pylori treatment. Sometimes the doctor will prescribe anti-ulcer medication.
Prevention
The infection can be prevented through appropriate personal and environmental hygiene. Eating utensils and drinking glasses should never be shared.
Patients or their family members with suspected but unconfirmed infection of H. pylori should consult a doctor and prevent cross-contamination.
*The above information is for reference only, please consult your doctor for detail.