Helicobacter pylori
Jen Kresse

Helicobacter pylori is one of the most important bacteria that is found in the human stomach. H. pylori is responsible for nine out of ten ulcers, not spicy food or stress. Over 25 million Americans endure ulcers. Because the majority of ulcers are caused by H. pylori, they can be cured with antibiotics and cured for good.
H. pylori is a gram-negative bacterium that is helical in shape. It is approximately 3 micrometers in length and has between 4-6 flagella. Under certain circumstances, it has the ability to convert from helical to a coccoidal form. H. pylori is a microaerophilic and it tests positive for oxidase and catalase. It is the only microorganism that can survive for extended periods in the acidic environment of the stomach. Because of its intense survival rate, it was difficult to truly identify it. The flagellum helps H. pylori to move through the layer of the mucus layer of the stomach. It produces adhesion, which helps it adhere to the epithelial cells. The production of urease is dependent on the survival of H. pylori and will eventually die without it.

H. pylori was originally discovered in 1875 by a German scientist but it was easily forgotten because it could not be cultured. It was rediscovered in 1979 by Robin Warren, an Australian pathologist and Barry Marshall. They were the first to extract the organism from a human stomach, isolate it, and culture it. They originally postulated that H. pylori was the real cause for the majority of ulcers and gastritis but the medical community was hesitant because of the low pH level of the stomach and believed that no microorganism could survive. Mr. Marshall took his experiments to the extreme; he swallowed a Petri dish that contained H. pylori. He developed gastritis and was able to isolate H. pylori from his stomach. Marshall also postulated because it was a bacteria, that it can be cured with antibiotics. He then took a round of antibiotics and within 14 days he was cured. Because of this experiment, Marshall and Warren won the Noble Prize in Medicine in 2005.

H. pylori was originally named Campylobacter pyloridis then C. pylori. After research, it was discovered that H. pylori did not belong in the Campylobacter genus and was then decided that it deserved its own genus. The pylori is greek in origin from Pylorus, which means gatekeeper. The pylori is thought to refer to the pyloric valve.
H. pylori can be diagnosed with either invasive or noninvasive techniques. Invasive means include doing an endoscopy and collecting small samples of stomach lining. The noninvasive means include blood antibody test, stool test or a carbon urea breath test. If H. pylori is not properly treated, it is believed that it will persist for life. It is also believed that 2/3 of the worlds population is infected with H. pylori, making it the most widespread infection. Only a select proportion actually experience symptoms and then are treated. H. pylori is spread similar as Salmonella typhi, improper hand washing and poor food preparation. H. pylori is typically treated with a one week triple-therapy: amoxicillin, clarithromycin, and omeprazole. Unfortunately, H. pylori is becoming resistant to the antibiotics and research is continuing for more medical options.

All in all H. pylori is an interesting microbe and deserves the credit of being the most resilient microorganism that exists in the stomach.


"Helicobacter pylori” http://www.nlm.nih.gov/medlineplus/ency/article/000229.htm

"H. pylori and Cancer: Fact Sheet” http://www.cancer.gov/cancertopics/factsheet/HPylori

"Helicobacter pylori and Peptic Ulcer Disease” http://www.cdc.gov/ulcer/

"Helicobacter pylori” http://en.wikipedia.org/wiki/Helicobacter_pylori

*Disclaimer - This report was written by a student participaring in a microbiology course at the Missouri University of Science and Technology. The accuracy of the contents of this report is not guaranteed and it is recommended that you seek additional sources of information to verify the contents.


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