Review article: the control of gastric acid and Helicobacter pylori eradication

This review focuses on the gastric acid pump as a therapeutic target for th e control of acid secretion in peptic ulcer and gastro-oesophageal reflux d isease. The mechanism of the proton pump inhibitors is discussed as well as their clinical use. The biology of Helicobacter pylori as a gastric denize n is then discussed, with special regard to its mechanisms of acid resistan ce. Here the properties of the products of the urease gene clusters, ureA, B and ureI, E, F, G and H are explored in order to explain the unique locat ion of this pathogen. The dominant requirement for acid resistance is the p resence of a proton gated urea transporter, UreI, which increases access of gastric juice urea to the intrabacterial urease 300-fold. This enables rap id and continuous buffering of the bacterial periplasm to approximate to pH 6.0, allowing acid resistance and growth at acidic pH in the presence of 1 mM urea. A hypothesis for the basis of combination therapy for eradication is also presented.