Helicobacter pylori was discovered by J Robin Warren and Barry Marshall. Their work was published in 1983 in a Journal “The Lancet”.

Although Warren and Marshall have firmly established the existence of curved-shaped bacteria, Helicobacter pylori, in the stomach cell lining, the presence of such bacteria was realized long ago in the late 19th century. However, such observations were considered artifacts and neglected due to the lack of proper equipment, particularly for collecting biopsies, and the widespread belief that the stomach environment is sterile because of its hostile nature (highly acidic environment). Warren and Marshall went against these prevailing thoughts. They proved not only the presence of the bacteria in the stomach but also established a link between Helicobacter pylori and gastritis & peptic ulcers by performing a series of experiments involving microscopic analysis of several biopsies, culturing bacteria in the laboratory, and ingesting Helicobacter pylori culture by himself and later by volunteers. Although, their findings initially met with skepticism, later work by them and others firmly established Helicobacter pylori role in several diseases including adenocarcinoma. Later in 1994, WHO recognized Helicobacter pylori as a Type I carcinogen. In 2005, Warren and Marshall were awarded the Nobel Prize in Medicine for their contribution to understanding gastrointestinal disorders/diseases and their relation with Helicobacter pylori. 

REFERENCES

• Marshall & Warren, 1983. Unidentified curved bacilli on gastric epithelium in active chronic gastritis. Lancet. 1(8336), 1273-1275. PMID-6134060; Full-Text Link: thelancet
• Marshall & Warren, 1984. Unidentified curved bacilli in the stomach of patients with gastritis and peptic ulceration. Lancet. 1(8390), 1311-1315. PMID-6145023; Full-Text Link: thelancet