Helicobacter pylori – the true stomach bug.
Helicobacter pylori – the true stomach bug.

Helicobacter pylori – the true stomach bug.

by Kaleigh Isaac, Physiology Assistant

Key take aways

  • H. pylori is a unique microbe that can grow in the stomach
  • H. pylori infection can cause stomach ulcers and increase the risk of stomach cancer
  • The symptoms of H. pylori are stomach pain or burning, nausea, and bloating
  • The urea breath test is the most effective way to diagnose H. pylori
  • Eradicating H. pylori can improve gut and skin issues, such as rosacea

What is it?

Helicobacter pylori (H. pylori) is a spiral-shaped species of bacteria that can be found in the human stomach, which is typically too acidic for most bacteria to grow. To be able to inhabit such a hostile environment, H. pylori has adopted an effective mechanism for survival. The bacteria produce an enzyme called urease, which buffers stomach acid by creating ammonia. Transmission of H. pylori occurs most frequently via the oral-oral route (1), but it is also possible to contract H. pylori by faecal-oral transmission following ingestion of contaminated water or food.

Approximately 4.4 billion individuals worldwide are infected by H. pylori (2). It is most common in Africa, South America, and Western Asian, but the infection doesn’t always produce symptoms. Therefore, the clinical importance of H. pylori infections has been questioned. However, H pylori infection can lead to the development of stomach ulcers with 70-80% of stomach ulcers and over 60% of cases of gastritis (stomach inflammation) thought to be caused by H pylori infection (3). Furthermore, persistent H. pylori infection is a primary risk factor for stomach cancer.

What are the symptoms?

The most frequently reported symptoms are stomach pain or discomfort, nausea, bloating, and loss of appetite and/or weight. H. pylori may contribute to the development of functional dyspepsia, a disorder of the gut-brain interaction, that shares many of the symptoms of H. pylori.

Whilst H. pylori can lead to gastrointestinal symptoms, some studies suggest that it is associated with extra-gastric disorders, such as cardiovascular disease, Alzheimer’s disease and dementia, high blood pressure, migraines, and rosacea (1). The supporting evidence for these associations remains weak, so further research is required before a direct link can be established. Although, rosacea has been shown to improve markedly following the treatment eradication of H. pylori (5). In addition, patients with H. pylori are more likely to have food intolerances, such as histamine or lactose intolerance (6).

How do you test for it?

There are a wide range of tests available for H pylori. These can be categorised into invasive or non-invasive tests. An endoscopy is an example of an invasive test for H. pylori, whilst non-invasive tests include the stool antigen test and the carbon-13 urea breath test.

An endoscopy involves the insertion of a long, thin tube into the upper gastrointestinal tract via the mouth, enabling clinicians to visualise any abnormalities. This diagnostic tool is often employed for patients that are above 45 years old or in younger patients that have alarm symptoms or family history of gastric cancer. During endoscopy, a sample of the stomach tissue is taken and tested for H pylori. However, it is an uncomfortable, expensive, and time-consuming procedure.

The stool antigen test involves providing a stool sample and detecting antibodies produced in response to infection by H. pylori. The urea breath test involves ingesting a sample of carbon-13 labelled urea. If H. pylori are present, the bacteria will break down the urea into ammonia and carbon dioxide, and the carbon dioxide is detected in breath. The non-invasive nature of both these tests mean they are often the favoured mode of diagnosis in the primary care setting. However, guidelines suggest that the urea breath test is the most effective method due to its higher sensitivity and lower cost (5). In addition, the urea breath test can be done at home.

How do you treat it?

H. pylori is treated with a triple-therapy regimen, comprising a proton pump inhibitor (PPI) and two different kinds of antibiotic (3). The PPI is used to reduce the amount of stomach acid produced, allowing the lining of the stomach to heal and the antibiotics target the bacteria. Once the treatment regimen is completed, it is recommended that the patient re-test using the carbon-13 breath test to confirm the infection has been cleared.

Additionally, eradication therapy for H. pylori is highly effective for the treatment of functional dyspepsia in patients that had also tested positive for H. pylori (7). Whilst the mechanism of action isn’t yet understood, eradication of H. pylori has been shown to improve and even cure functional dyspepsia symptoms (7). Therefore, in patients with symptoms of nausea, bloating, and epigastric pain or discomfort, testing for H. pylori, such as with the urea breath test, is recommended.


  1. Gravina, A. G., Zagari, R. M., De Musis, C., Romano, L., Loguercio, C., & Romano, M. (2018). Helicobacter pylori and extragastric diseases: A review. World journal of gastroenterology, 24(29), 3204–3221. https://doi.org/10.3748/wjg.v24.i29.3204.
  2. Hooi, J., Lai, W., Ng, W., Suen, M., Underwood, F., & Tanyingoh, D. et al. (2017). Global Prevalence of Helicobacter pylori Infection: Systematic Review and Meta-Analysis. Gastroenterology, 153(2), 420-429. doi: 10.1053/j.gastro.2017.04.022
  3. NICE Excellence. (2022). Helicobacter pylori infection | Treatment summary | BNF content published by NICE. Retrieved 8 March 2022, from https://bnf.nice.org.uk/treatment-summary/helicobacter-pylori-infection.html
  4. Gravina A, Federico A, Ruocco E, Lo Schiavo A, Masarone M, Tuccillo C, Peccerillo F, Miranda A, Romano L, de Sio C, de Sio I, Persico M, Ruocco V, Riegler G, Loguercio C, Romano M. Helicobacter pylori infection but not small intestinal bacterial overgrowth may play a pathogenic role in rosacea. United European Gastroenterol J. 2015
  5. Malfertheiner, P., Megraud, F., O’morain, C. A., Gisbert, J. P., Kuipers, E. J., Axon, A. T., … & El-Omar, E. M. (2017). Management of Helicobacter pylori infection—the Maastricht V/Florence consensus report. Gut, 66(1), 6-30.
  6. Schnedl, W. J., Meier-Allard, N., Schenk, M., Lackner, S., Enko, D., Mangge, H., & Holasek, S. J. (2022). Helicobacter pylori infection and lactose intolerance increase expiratory hydrogen . EXCLI Journal, 21, 426-435
  7. Ford, A. C., Tsipotis, E., Yuan, Y., Leontiadis, G. I., & Moayyedi, P. (2022). Efficacy of Helicobacter pylori eradication therapy for functional dyspepsia: updated systematic review and meta-analysis. Gut.