H. pylori
Also called: Helicobacter pylori, stomach bacteria infection
Helicobacter pylori is a bacterium that lives in the stomach lining. About a third of UK adults carry it; most have no symptoms. In a minority it causes gastritis, peptic ulcers, and rare cancers. Standard treatment is a 7 to 14 day course of two antibiotics plus a proton pump inhibitor, which clears the infection in 80 to 90 percent of cases on the first try.
Why it matters
H. pylori is the only bacterium known to thrive in stomach acid. It survives by burrowing into the stomach lining and producing urease, which neutralises acid locally. Most carriers are asymptomatic. But over decades, the immune response to H. pylori can damage the lining, producing chronic gastritis, peptic ulcers, and (rarely) gastric cancer or MALT lymphoma.
Symptoms when it does cause problems
- Burning pain in the upper abdomen, often worse on an empty stomach.
- Nausea, especially in the morning.
- Bloating and frequent burping.
- Loss of appetite and unexpected weight loss.
- Bad breath that does not respond to oral hygiene.
- Iron deficiency anaemia not explained by diet or periods.
Red flag symptoms
- Vomiting blood or stools that look black and tarry.
- Difficulty or pain on swallowing.
- Persistent vomiting.
- Significant unintentional weight loss.
- These warrant urgent referral and endoscopy.
How it is tested
- Urea breath test (most common, non-invasive).
- Stool antigen test.
- Endoscopy with biopsy (gold standard, used when symptoms suggest ulcer or cancer).
- Stop PPI medication for at least 2 weeks before testing or you will get a false negative.
- Stop antibiotics for at least 4 weeks before testing for the same reason.
Treatment
- First-line (NICE CKS): 7 day triple therapy. Non-penicillin-allergic: PPI + amoxicillin + clarithromycin OR PPI + amoxicillin + metronidazole (metronidazole is the alternative to clarithromycin, not a substitute for amoxicillin). Penicillin-allergic: PPI + clarithromycin + metronidazole.
- Second-line: 14 day quadruple therapy. PPI + bismuth + tetracycline + metronidazole.
- Confirm eradication with a follow-up urea breath test 4 weeks after finishing antibiotics.
- Resistance to clarithromycin is rising; some areas now start with the quadruple regimen.
- Re-infection rates after successful eradication are low (under 2 percent per year).
Common questions
- Can I have H. pylori without symptoms?
- Yes, most carriers do. Around 50 percent of the global population carry H. pylori; only 10 to 20 percent develop symptoms over their lifetime. Routine screening of asymptomatic adults is not currently recommended.
- Is H. pylori contagious?
- Mildly. Most transmission happens in childhood within families through shared food, saliva and water. Adult-to-adult transmission is uncommon. There is no need to isolate.
- Can probiotics treat H. pylori?
- Not on their own. Some Lactobacillus and Saccharomyces boulardii strains alongside antibiotics improve eradication rates by 5 to 10 percent and reduce side effects of the antibiotics. They are an adjunct, not a replacement.
- Does H. pylori cause IBS?
- Not directly. Some people with chronic H. pylori develop IBS-like symptoms that improve with eradication. Most IBS is unrelated to H. pylori. Test only if there are upper-GI symptoms.