Helicobacter Pylori

Helicobacter Pylori Background

Helicobacter pylori, previously known as Campylobacter pylori, is a gram-negative, helically-shaped, microaerophilic bacterium usually found in the stomach. Its helical shape (from which the genus name, helicobacter, derives) is thought to have evolved in order to penetrate the mucoid lining of the stomach and thereby establish infection. H. pylori causes chronic gastritis and has been associated with several serious diseases of the gastrointestinal tract, including duodenal ulcer and gastric cancer (Brown, 2000). It has also been linked to neurological, dermatological, hematologic, ocular, cardiovascular, metabolic, allergic and hepatobiliary disease manifestations (Gravina et al., 2018).

The prevalence of H. pylori infection varies widely by geographic area, age, race, ethnicity, and social-economic status, with higher rates in developing countries, amongst children, which decreases with improvements in hygiene practices. Generally, inadequate sanitation practices, low social class, and crowded or high-density living conditions seem to be related to a higher prevalence of H. pylori infection.  Transmission is person to person, by either the oral-oral route (through vomitus or possibly saliva) or perhaps the fecal-oral route. Waterborne transmission, probably due to fecal contamination, may also be a source of infection (Brown, 2000; Burucoa & Axon, 2017).

During chronic infection, H. pylori resides within the gastric mucosal layer, deep within invaginations known as glands and can persist for the host’s lifetime. Its ability to survive in the stomach is associated with urease production, chemotactic motility, and the ability to adapt to the fluctuating environment. Additionally, biofilm formation is believed to play a role in colonization (Hathroubi et al., 2018).

Testing usually requires a combination of tests, including endoscopy techniques, bacterial culture from gastric biopsy, urea breath test, and stool antigen. Serology was one of the first methods used for diagnosis of H. pylori infection and is recommended for initial screening, requiring further confirmation by histology and/or culture before treatment (Lopes et al., 2014).

References

• Brown LM (2000). Helicobacter pylori: epidemiology and routes of transmission. Epidemiol Rev. 22 (2): 283–97.
• Burucoa C, Axon A. Epidemiology of Helicobacter pylori infection. Helicobacter. 2017;22 Suppl 1:10.1111/hel.12403.
• Lopes AI, Vale FF, Oleastro M. Helicobacter pylori infection – recent developments in diagnosis. World J Gastroenterol. 2014;20(28):9299‐9313.
• Gravina AG, Zagari RM, De Musis C, Romano L, Loguercio C, Romano M. Helicobacter pylori and extragastric diseases: A review. World J Gastroenterol. 2018;24(29):3204‐3221.
• Hathroubi S, Servetas SL, Windham I, Merrell DS, Ottemann KM. Helicobacter pylori Biofilm Formation and Its Potential Role in Pathogenesis. Microbiol Mol Biol Rev. 2018;82(2):e00001-18.