Helicobacter pylori or H. pylori is a pathogenic bacterium that takes its name from its spiral shape and develops in the human gastric mucosa(1).
H. pylori infection is one of the most common chronic bacterial infections and a major cause of morbidity and mortality worldwide, affecting an estimated 50% of the world’s population(2) The prevalence of H. pylori infection varies considerably according to geographic area, age, ethnicity and socio-economic status. There are major differences between developed and developing countries(1). In Europe, the lowest prevalence rates have been observed in Northern Europe, while the highest rates have been found in Eastern and Southern Europe, with up to 84% in Portugal and Poland(3). In France, prevalence is around 15-30%. It is lower in people under 30 (less than one in five) and more frequent after the age of 50-60 (around one in two)(4).
H. pylori infection is usually transmitted during childhood. For the general population, the most likely mode of transmission is person-to-person, mainly oral (via vomitus or saliva). Waterborne transmission, probably due to fecal contamination, can also be a major source of infection, especially in parts of the world where untreated water is common(1). The mode of transmission implies proximity, which is why Helicobacter pylori is most often transmitted within the same family(5).
What are the consequences of Helicobacter pylori infection?
The Helicobacter pylori bacterium causes inflammation of the lining of the stomach, called gastritis, which persists for life if the infection is left untreated. In 80% of cases, the infection remain asymptomatic and can therefore go undetected(8). However, the infection can lead to more severe complications:
- Ulcers: 90% of patients with duodenal ulcers and 70-90% of patients with gastric ulcers have H. pylori infection(8).
- Stomach cancer: since 1994, H. pylori has been classified as a class I carcinogen, i.e. carcinogenic to humans (7); infection is thought to be associated with 90% of gastric cancer cases(6).
It is estimated that 6-10% of infected patients will develop an ulcer and 1% will develop gastric adenocarcinoma after several decades(4).
When and how to test for H. pylori infection?
The decision to test for H. pylori should only be made with the intention of treating patients with (7):
- gastric or duodenal peptic ulcer disease (active ulcer or history of ulcer),
- low-grade gastric MALT (mucosal-associated lymphoid tissue),
- after resection of early gastric cancer,
- chronic dyspepsia,
- 1st-degree relatives of patients with gastric cancer,
- first-generation immigrants from an area with high prevalence of Helicobacter pylori infection,
- unexplained iron-deficiency anemia when other causes have been included,
- idiopathic thrombocytopenic purpura,
- long-term treatment with proton pump inhibitors (PPIs), aspirin or non-steroidal anti-inflammatory drugs (NSAIDs).
Diagnostic methods for the detection of H. pylori are based on invasive and non-invasive test procedures(6):
- Invasive tests require gastroscopy with biopsies, and include the rapid urease test (RUT),
- histological evaluation, bacterial culture and gene amplification (i.e. by PCR), enabling direct detection of H. pylori genetic material(6).
- Non-invasive methods include the 13C urea breath test (UBT), serology and stool antigen test(6).
- Gastroscopy with biopsies can be used to test for H. pylori infection and also to detect precancerous lesions on pathological examination(4).
How is H. pylori infection treated in adults?
Treatment of infection and prevention of complications or recurrence are based on eradication of the bacteria (8,9).
Therapeutic regimens are based on the combination of a proton pump inhibitor and antibiotics. As antibiotic resistance is a growing problem affecting the efficacy of treatments for Helicobacter pylori infection, first-line treatment should be selected according to regional or individual H. pylori antibiotic resistance patterns(6)
Lastly, the success of treatment depends on patient information and adherence and on a coordinated management between gastroenterologist and general practitioner(9).