What Is H. pylori? The Stomach Bacterium Behind Most Ulcers
Helicobacter pylori (H. pylori) is a spiral-shaped bacterium that lives in the stomach lining. It is one of the most common infections in the world: estimates suggest that around half of all people carry it, with the highest rates in parts of Africa, Latin America and Western Asia, and lower rates in North America, Western Europe and Oceania.
How it survives in the stomach
The stomach is extremely acidic, which kills most bacteria. H. pylori survives by burrowing into the protective mucus layer and producing an enzyme called urease, which neutralises acid around it. From there it can inflame the stomach lining for years.
How people catch it
Infection usually happens in childhood. It is thought to spread:
- From person to person, through saliva, vomit or faeces
- Through contaminated water or food, especially where sanitation is limited
- Within families, which is why several household members are often infected
What it can cause
Most people with H. pylori never develop symptoms. In others it causes:
- Gastritis, inflammation of the stomach lining
- Peptic ulcers in the stomach or duodenum
- In a small minority, over many years, a higher risk of stomach cancer and a rare lymphoma called MALT lymphoma
The World Health Organization's cancer agency classifies H. pylori as a Group 1 carcinogen, which describes how certain the link is, not how likely an individual is to develop cancer.
How it is diagnosed
- Urea breath test: accurate, simple and widely used
- Stool antigen test: accurate and inexpensive
- Endoscopy with biopsy: used when a camera examination is needed anyway
- Blood antibody test: shows past exposure but cannot confirm a current infection or a cure
How it is treated
Treatment combines an acid-reducing medicine with two or more antibiotics, often with bismuth, usually for 10 to 14 days. Which combination is best depends on local antibiotic resistance, so treatment should always be prescribed by a doctor. A follow-up test at least four weeks after treatment confirms whether the infection has gone.
The encouraging part
H. pylori is very treatable. With the right regimen, taken exactly as prescribed, most people clear the infection, and their ulcers heal and are much less likely to return.
