Helicobacter pylori
Kahn Powell

It has long been the belief that ulcers within the stomach were a reaction to emotional stress.  The connection was based on the following: mucous secretions depend on blood flow in the mucosal tissue.  During events of high stress the brain sends signals to the stomach which result in decreased blood flow for a short periods, With a constant level of emotional stress, mucosal secretions would diminish, allowing exposure of the cells which line the stomach to the harsh conditions within the stomach.  If this were to occur frequently enough, that 'burning' feeling that we have when stressed could cause an ulcer.

Barry Marshall, a physician in Australia, treated patients suffering from chronic gastritis and peptic ulcer disease, He had taken biopsies from his patients' mucosal stomach linings and upon studying them isolated and cultured a new bacterium, Helicobacter pylori.  It seemed that this organism was present in almost all of his patients with peptic ulcers (95%), and every one of his patients with chronic gastritis.  This discovery was made in 1982 along with the fact that H. pylori can not be isolated from the majority of people who have no problems with ulcers.  He believes that as many as 20% of Americans may have this organism in their digestive tracts.

Since then, quick and easy methods have been developed to detect and treat this organism with a 90% rate of success.  Administration of 14C-labeled urea to the stomach orally and detecting 14C labeled C02 on the patients breath indicates that the patient is infected with H. pylori.  Since this bacterium survives in the harsh, acidic environment of the stomach, it needs a way to protect itself.  This is done through conversion of urea to C02 and NH3.  The ammonia buffers the acid that immediately surrounds the organism and allows it to survive.  Other metabolic products of the bacterium are what damage the mucosa which lead to the stomach's own gastric juices eroding its lining, Once the organism is detected, it can be treated with a variety of medications.  One of them is clarithromycin and omeprozol for 7 to 15 days.

H. pylori is a Gram negative, spiral-shaped proteobacterium that is approximately 0.5 to 1.0 um in diameter with polar flagella.  It is an anoxygenic phototroph which does not ferment sugars.  It is placed in the epsilon-subgroup of the proteobacteria by its 16S rRNA.

 

 

*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.

 

Return to Missouri S&T Microbiology HomePage Go to DJW's HomePage