Helicobacter pylori infection overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Helicobacter pylori (H. pylori), previously named Campylobacter pyloridis, is a Gram-negative, microaerophilic bacterium found in the stomach. It is also linked to the development of duodenal ulcers and stomach cancer. However, over 80 percent of individuals infected with the bacterium are asymptomatic and it has been postulated that it may play an important role in the natural stomach ecology.[1]
More than 50% of the world's population harbor H. pylori in their upper gastrointestinal tract. Infection is more prevalent in developing countries, and incidence is decreasing in Western countries. H. pylori's helix shape (from which the generic name is derived) is thought to have evolved to penetrate the mucoid lining of the stomach.[2][3]
Historical Perspective
It was identified in 1982 by Barry Marshall and Robin Warren, who found that it was present in patients with chronic gastritis and gastric ulcers, conditions that were not previously believed to have a microbial cause.
Pathophysiology
Helicobacter pylori (H. pylori) is a bacterium that lives on the lining of the stomach. Although we used to think that spicy food, acid, and stress were the major causes of ulcers, we now know that nine out of ten ulcers are caused by H. pylori. Medicines that reduce stomach acid may make you feel better, but your ulcer may come back. Here's the good news: Since most ulcers are caused by this bacterial infection, they can be cured with the right antibiotics.
Epidemiology and Demographics
Approximately two-thirds of the world's population is infected with H. pylori. In the United States, H. pylori is more prevalent among older adults, African Americans, Hispanics, and lower socioeconomic groups.
Approximately 25 million Americans suffer from peptic ulcer disease at some point in their lifetime. Each year there are 500,000 to 850,000 new cases of peptic ulcer disease and more than one million ulcer-related hospitalizations.
Risk Factors
Recent studies have shown an association between long-term infection with H. pylori and the development of gastric cancer. Gastric cancer is the second most common cancer worldwide; it is most common in countries such as Colombia and China, where H. pylori infects over half the population in early childhood. In the United States, where H. pylori is less common in young people, gastric cancer rates have decreased since the 1930s.
Treatment
Medical Therapy
Persons with active gastric or duodenal ulcers or documented history of ulcers should be tested for H. pylori, and if found to be infected, they should be treated. To date, there has been no conclusive evidence that treatment of H. pylori infection in patients with non-ulcer dyspepsia is warranted. Testing for and treatment of H. pylori infection are recommended following resection of early gastric cancer and for low-grade gastric MALT lymphoma. Retesting after treatment may be prudent for patients with bleeding or otherwise complicated peptic ulcer disease. Treatment recommendations for children have not been formulated. Pediatric patients who require extensive diagnostic work-ups for abdominal symptoms should be evaluated by a specialist.
Primary Prevention
Since the source of H. pylori is not yet known, recommendations for avoiding infection have not been made. In general, it is always wise for persons to wash hands thoroughly, to eat food that has been properly prepared, and to drink water from a safe, clean source.
References
- ↑ Blaser, M. J. (2006). "Who are we? Indigenous microbes and the ecology of human diseases" (PDF). EMBO Reports. 7 (10): 956–60. doi:10.1038/sj.embor.7400812. PMC 1618379. PMID 17016449.
- ↑ Yamaoka, Yoshio (2008). Helicobacter pylori: Molecular Genetics and Cellular Biology. Caister Academic Pr. ISBN 1-904455-31-X.
- ↑ Brown LM (2000). "Helicobacter pylori: epidemiology and routes of transmission" (PDF). Epidemiol Rev. 22 (2): 283–97. PMID 11218379.