Helicobacter pylori

Helicobacter pylori
Electron micrograph of H. pylori possessing multiple flagella (negative staining)
Scientific classification Edit this classification
Domain: Bacteria
Phylum: Campylobacterota
Class: "Campylobacteria"
Order: Campylobacterales
Family: Helicobacteraceae
Genus: Helicobacter
Species:
H. pylori
Binomial name
Helicobacter pylori
(Marshall et al. 1985) Goodwin et al., 1989
Synonyms
  • Campylobacter pylori Marshall et al. 1985

Helicobacter pylori, previously known as Campylobacter pylori, is a gram-negative, flagellated, helical bacterium. Mutants can have a rod or curved rod shape that exhibits less virulence.[1][2] Its helical body (from which the genus name Helicobacter derives) is thought to have evolved to penetrate the mucous lining of the stomach, helped by its flagella, and thereby establish infection.[3][2] The bacterium was first identified as the causal agent of gastric ulcers in 1983 by Australian physician-scientists Barry Marshall and Robin Warren.[4][5] In 2005, they were awarded the Nobel Prize in Physiology or Medicine for their discovery.[6]

Infection of the stomach with H. pylori is not the cause of illness itself: over half of the global population is infected, but most individuals are asymptomatic.[7][8] Persistent colonization with more virulent strains can induce a number of gastric and non-gastric disorders.[9] Gastric disorders due to infection begin with gastritis, or inflammation of the stomach lining.[10] When infection is persistent, the prolonged inflammation will become chronic gastritis. Initially, this will be non-atrophic gastritis, but the damage caused to the stomach lining can bring about the development of atrophic gastritis and ulcers within the stomach itself or the duodenum (the nearest part of the intestine).[10] At this stage, the risk of developing gastric cancer is high.[11] However, the development of a duodenal ulcer confers a comparatively lower risk of cancer.[12] Helicobacter pylori is a class 1 carcinogenic bacteria, and potential cancers include gastric MALT lymphoma and gastric cancer.[10][11] Infection with H. pylori is responsible for an estimated 89% of all gastric cancers and is linked to the development of 5.5% of all cases cancers worldwide.[13][14] H. pylori is the only bacterium known to cause cancer.[15]

Extragastric complications that have been linked to H. pylori include anemia due either to iron deficiency or vitamin B12 deficiency, diabetes mellitus, cardiovascular illness, and certain neurological disorders.[16] An inverse association has also been claimed with H. pylori having a positive protective effect against asthma, esophageal cancer, inflammatory bowel disease (including gastroesophageal reflux disease and Crohn's disease), and others.[16]

Some studies suggest that H. pylori plays an important role in the natural stomach ecology by influencing the type of bacteria that colonize the gastrointestinal tract.[17][18] Other studies suggest that non-pathogenic strains of H. pylori may beneficially normalize stomach acid secretion, and regulate appetite.[19]

In 2023, it was estimated that about two-thirds of the world's population was infected with H. pylori, being more common in developing countries.[20] The prevalence has declined in many countries due to eradication treatments with antibiotics and proton-pump inhibitors, and with increased standards of living.[21][22]

  1. ^ Martínez LE, O'Brien VP, Leverich CK, Knoblaugh SE, Salama NR (July 2019). "Nonhelical Helicobacter pylori Mutants Show Altered Gland Colonization and Elicit Less Gastric Pathology than Helical Bacteria during Chronic Infection". Infect Immun. 87 (7). doi:10.1128/IAI.00904-18. PMC 6589060. PMID 31061142.
  2. ^ a b Salama NR (April 2020). "Cell morphology as a virulence determinant: lessons from Helicobacter pylori". Curr Opin Microbiol. 54: 11–17. doi:10.1016/j.mib.2019.12.002. PMC 7247928. PMID 32014717.
  3. ^ Rust M, Schweinitzer T, Josenhans C (2008). "Helicobacter Flagella, Motility and Chemotaxis". In Yamaoka, Y. (ed.). Helicobacter pylori: Molecular Genetics and Cellular Biology. Caister Academic Press. ISBN 978-1-904455-31-8. Archived from the original on 18 August 2016. Retrieved 1 April 2008.
  4. ^ Warren JR, Marshall B (June 1983). "Unidentified curved bacilli on gastric epithelium in active chronic gastritis". Lancet. 1 (8336): 1273–5. doi:10.1016/S0140-6736(83)92719-8. PMID 6134060. S2CID 1641856.
  5. ^ FitzGerald R, Smith SM (2021). "An Overview of Helicobacter pylori Infection". Helicobacter Pylori. Methods Mol Biol. Vol. 2283. pp. 1–14. doi:10.1007/978-1-0716-1302-3_1. ISBN 978-1-0716-1301-6. PMID 33765303. S2CID 232365068.
  6. ^ Watts G (October 2005). "Nobel prize is awarded to doctors who discovered H pylori". BMJ. 331 (7520): 795. doi:10.1136/bmj.331.7520.795. PMC 1246068. PMID 16210262.
  7. ^ "Helicobacter pylori (H. pylori) and Cancer - NCI". www.cancer.gov. 25 September 2013. Archived from the original on 19 October 2023. Retrieved 18 October 2023.
  8. ^ de Brito BB, da Silva FA, Soares AS, Pereira VA, Santos ML, Sampaio MM, et al. (October 2019). "Pathogenesis and clinical management of Helicobacter pylori gastric infection". World J Gastroenterol. 25 (37): 5578–5589. doi:10.3748/wjg.v25.i37.5578. PMC 6785516. PMID 31602159.
  9. ^ Chen CC, Liou JM, Lee YC, Hong TC, El-Omar EM, Wu MS (2021). "The interplay between Helicobacter pylori and gastrointestinal microbiota". Gut Microbes. 13 (1): 1–22. doi:10.1080/19490976.2021.1909459. PMC 8096336. PMID 33938378.
  10. ^ a b c Matsuo Y, Kido Y, Yamaoka Y (March 2017). "Helicobacter pylori Outer Membrane Protein-Related Pathogenesis". Toxins. 9 (3): 101. doi:10.3390/toxins9030101. PMC 5371856. PMID 28287480.
  11. ^ a b Marghalani AM, Bin Salman TO, Faqeeh FJ, Asiri MK, Kabel AM (June 2020). "Gastric carcinoma: Insights into risk factors, methods of diagnosis, possible lines of management, and the role of primary care". J Family Med Prim Care. 9 (6): 2659–2663. doi:10.4103/jfmpc.jfmpc_527_20. PMC 7491774. PMID 32984103.
  12. ^ Koga Y (December 2022). "Microbiota in the stomach and application of probiotics to gastroduodenal diseases". World J Gastroenterol. 28 (47): 6702–6715. doi:10.3748/wjg.v28.i47.6702. PMC 9813937. PMID 36620346.
  13. ^ Shin WS, Xie F, Chen B, Yu J, Lo KW, Tse GM, et al. (October 2023). "Exploring the Microbiome in Gastric Cancer: Assessing Potential Implications and Contextualizing Microorganisms beyond H. pylori and Epstein-Barr Virus". Cancers. 15 (20): 4993. doi:10.3390/cancers15204993. PMC 10605912. PMID 37894360.
  14. ^ Violeta Filip P, Cuciureanu D, Sorina Diaconu L, Maria Vladareanu A, Silvia Pop C (2018). "MALT lymphoma: epidemiology, clinical diagnosis and treatment". Journal of Medicine and Life. 11 (3): 187–193. doi:10.25122/jml-2018-0035. PMC 6197515. PMID 30364585.
  15. ^ Ruggiero P (November 2014). "Use of probiotics in the fight against Helicobacter pylori". World J Gastrointest Pathophysiol. 5 (4): 384–91. doi:10.4291/wjgp.v5.i4.384. PMC 4231502. PMID 25400981.
  16. ^ a b Santos ML, de Brito BB, da Silva FA, Sampaio MM, Marques HS, Oliveira E, et al. (July 2020). "Helicobacter pylori infection: Beyond gastric manifestations". World J Gastroenterol. 26 (28): 4076–4093. doi:10.3748/wjg.v26.i28.4076. PMC 7403793. PMID 32821071.
  17. ^ Cite error: The named reference Blaser 2006 was invoked but never defined (see the help page).
  18. ^ Gravina AG, Zagari RM, De Musis C, Romano L, Loguercio C, Romano M (August 2018). "Helicobacter pylori and extragastric diseases: A review". World Journal of Gastroenterology (Review). 24 (29): 3204–3221. doi:10.3748/wjg.v24.i29.3204. PMC 6079286. PMID 30090002.
  19. ^ Ackerman J (June 2012). "The ultimate social network". Scientific American. Vol. 306, no. 6. pp. 36–43. doi:10.1038/scientificamerican0612-36. PMID 22649992.
  20. ^ "Helicobacter pylori | CDC Yellow Book 2024". wwwnc.cdc.gov. Archived from the original on 22 October 2023. Retrieved 20 October 2023.
  21. ^ Cite error: The named reference Li2023 was invoked but never defined (see the help page).
  22. ^ Hooi JK, Lai WY, Ng WK, Suen MM, Underwood FE, Tanyingoh D, et al. (August 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. PMID 28456631.