What Is Helicobacter Pylori Infection?
Helicobacter pylori, a gram-negative spiral bacterium, is the most common chronic bacterial infection in human beings. It wasn’t discovered until 1982. In 1994 it was recognized as a cause of gastric and duodenal ulcers and a prime carcinogen for gastric cancer. Since then, its relationship with colon cancer, pancreatic cancer, and hepatobiliary cancer has been suspected.
Person-to-person contact is the most likely transmission method. H. pylori is able to survive and proliferate in the gastric environment by manufacturing urease to neutralize acid, allowing it to penetrate the gastric mucus layer. Its mobility helps it move through the mucus layers to the gastric cells and attach to them.
It usually does not invade the tissue, but disrupts the mucus layer such that the tissue is more vulnerable to acid damage. Simultaneously, an immune response from both the innate immune system and the cellular immune system creates an inflammatory reaction to further injure the tissue. This can then serve as an etiology for the following:
- Acute and chronic gastritis (GERD).
- Duodenal ulcer (peptic ulcer diathesis): Chronic H. pylori infection is the most important risk for duodenal ulcer. Up to 10% of those infected will develop it, and it is present in most patients with duodenal ulcer not related to NSAID use
- Gastric cancer.
Eradication of H. pylori will usually mean a permanent eradication, since re-colonization is unusual.
How Is Helicobacter Pylori Infection Diagnosed?
It is protocol that testing for H. pylori is only performed if positive results will result in treatment. Those at risk for H. pylori and who have indications for testing are those with the following:
- Active peptic ulcer disease.
- Previous ulcer in which H. pylori eradication has not been proven.
- Early gastric cancer.
- Low grade gastric mucosa lymphoma.
Dyspepsia patients may be considered, as are patients on long-term NSAID or aspirin regimens, those who have iron deficiency or who suffer from immune thrombocytopenia.
- Non-invasive (without endoscopy) tests: Stool antigen test (detection of bacterial antigen) or urea breath test.
- Invasive (endoscopic) tests: Biopsy for urea release in tissues, histology of the tissue itself, and rarely, bacterial culture.
- Confirmation of eradication: All patients treated for H. pylori should be tested as a “proof of cure,” using the urea breath test, stool antigen test, or endoscopy-based testing if endoscopy is indicated for other reasons.
How to Manage Helicobacter Pylori Infection
Once Helicobacter pylori infection has been established, treatment is indicated. The treatment depends on macrolide (clarithromycin) and penicillin antibiotics, and for patients with macrolide resistance or with penicillin allergies, alternative treatments are used. Treatment is up to 14 days.
Traditional clarithromycin-based triple therapy (14 days):
- Protein pump inhibitor
- Amoxicillin. In those with a penicillin allergy, metronidazole (Flagyl) can be substituted
Alternative therapy for macrolide (clarithromycin) resistance.
Bismuth quadruple therapy (14 days):
Levofloxacin triple therapy (10-14 days):
- Protein pump inhibitor
Levofloxacin quadruple therapy (7-10 days):
Each of these categories of therapy have a “sequential version” that entails timing the agents along a skewed timeline.
Immunization for H. pylori is still investigational, although vaccination is sometimes considered as adjunctive therapy to enlist the help of the immune system during the various antibiotic regimens.
Eradication prevents duodenal ulcer recurrence, so the best preventative strategy is to undergo primary treatment for its eradication followed by a test of cure with the urease breath test or stool antigen test.
False negative results of testing can result if patients are on protein pump inhibitors prior, so this medication should be discontinued for 4 weeks before.
The other side of prevention is to mitigate the symptoms of the erosive diseases H. pylori causes. Bland diet, frequent meals, protein pump inhibitors, etc., are used to decrease symptoms, but this strategy becomes irrelevant when the prime concern is the presence of H. pylori which should be eradicated.