Helicobacter pylori

Helicobacter pylori is a Eubacterium that infects the mucus lining of the human stomach. Many peptic ulcers and some types of gastritis are caused by H. pylori infection, although most humans who are infected will never develop symptoms. This bacterium lives in the human stomach exclusively and is the only known organism that can thrive in that highly acidic environment. It is helix-shaped (hence the name helicobacter) and can literally screw itself into the stomach lining to colonize.

History

In 1875, German scientists found spiral bacteria in the lining of the human stomach; the bacteria could not be grown in culture and the results were eventually forgotten. (Blaser 2005)

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1875 - German

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In 1892, the Italian researcher Giulio Bizzozero described spiral bacteria living in the acidic environment of the stomach of dogs.

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1892 - Italian - Giulio Bizzozero

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Professor Walery Jaworski of the Jagiellonian University in Kraków investigated sediments of gastric washings obtained from humans in 1899. Among some rod-like bacteria, he also found bacteria with a characteristic spiral shape, which he called Vibrio rugula. He was the first to suggest a possible role of this organism in the pathogeny of gastric diseases. This work was included in the "Handbook of Gastric Diseases" but it did not have much impact as it was written in Polish. Jaworski was not able to culture the organism. (Konturek 2003).

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Walery Jaworski - Jagiellonian University - Kraków - 1899

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The bacterium was rediscovered in 1982 by two Australian scientists Robin Warren and Barry Marshall; they isolated the organisms from mucosal specimens from human stomachs and were the first to successfully culture them. In their original paper, Warren and Marshall contended that most stomach ulcers and gastritis were caused by colonization with this bacterium, not by stress or spicy food as had been assumed before.

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1982 - Australia - Robin Warren - Barry Marshall - Stress - Spicy food

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Some maintain that the medical community was slow to recognize the role of this bacterium in stomach ulcers and gastritis, believing that no bacterium could survive for long in the acidic environment of the stomach. The community began to come around after further studies were done, including one in which Marshall drank a petri-dish of H. pylori, developed gastritis, and the bacteria were recovered from his stomach lining, thereby satisfying three out of the four Koch's postulates. Marshall's gastritis later resolved without treatment. Marshall and Warren went on to show that antibiotics are effective in the treatment of gastritis. In 1994, the National Institutes of Health published an opinion stating that most recurrent gastric ulcers were caused by H. pylori, and recommended that antibiotics be included in the treatment regimen. In 2005, Warren and Marshall were awarded the Nobel Prize in Medicine for their work on H. pylori.

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Koch's postulates - 1994 - National Institutes of Health - 2005 - Nobel Prize in Medicine

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Before the appreciation of the bacterium's role, stomach ulcers were typically treated with medicines that neutralize stomach acid or decrease its production. While this worked well, the ulcers very often reappeared. A traditional medication against gastritis was bismuth subsalicylate. It was often effective, but fell out of use, since its mechanism of action was a mystery. Nowadays it is quite clear that it is due to the bismuth salt acting as an antibiotic. Today, many stomach ulcers are treated with antibiotics effective against H. pylori.

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The bacterium was initially called Campylobacter pyloridis, then C. pylori (after a correction to the Latin grammar) and in 1989, after DNA sequencing and other data showed that the bacterium did not belong in the Campylobacter genus, it was placed in its own genus Helicobacter. The name pylori comes from the Latin word pylorus, which means gatekeeper, and refers to the circular opening leading from the stomach into the duodenum.

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Latin grammar - 1989 - DNA sequencing - Campylobacter - Genus - Latin - Gatekeeper - Duodenum

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While H. pylori remain the most important known bacteria to inhabit the human stomach, several other species of the Helicobacter genus have now been identified in other mammals and some birds, and some of these can infect humans. Helicobacter species have also been found to infect the livers of certain mammals and to cause liver disease.

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Mammal - Bird - Liver

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