Gastric infection by Helicobacter pylori.

Helicobacter pylori infection causes chronic active gastritis, ulcer disease, and gastric cancer. Current eradication regimens use a proton pump inhibitor (PPI) and two antibiotics. Triple therapy now has a success rate less than 80%, below the cutoff for efficacious eradication. Antibiotic resistance, inconsistent acid control by PPIs, and poor patient compliance contribute to the failure rate. H. pylori is a neutralophile that has developed special acid acclimation mechanisms to colonize its acidic gastric niche. Identifying the components of these mechanisms will provide novel bactericidal drug targets. Alternatively, better 24-hour acid control would increase the efficacy of antibiotics, leading to dual therapy with improved PPIs and amoxicillin. Studies of acid acclimation by H. pylori have identified several potential eradication targets including UreI, alpha-carbonic anhydrase, and a two-component system. Continuing improvement of PPIs has led to the development of at least three candidate drugs with improved 24-hour acid control.