Helicobacter pylori: Recent advances in the study of its pathogenicity andprevention

Helicobacter pylori has acquired great importance during the last two decad es, after being recognized as an important pathogen that infects a great po rtion of the human population. This microorganism is recognized as the main causal agent of chronic gastritis and duodenal ulcers, and it is associate d with the subsequent development of gastric carcinoma. The pathogenic mech anisms of H. pylori and their relation to gastric ailments have not been cl early defined. However, at present it is well established that urease, vacu olating cytotoxin VacA, and the pathogenicity island (cag PAI) gene product s, are the main factors of virulence of this organism. Thus, individuals in fected with strains that express these virulence factors probably develop a severe local inflammation that may induce the development of peptic ulcer and gastric cancer. The way the infection spreads throughout the world sugg ests the possibility that there are multiple pathways of transmission. Due to the Importance that H. pylori has acquired as a human pathogen, laborato ries worldwide are attempting to develop a vaccine that confers long-term i mmunological protection against infection by this microorganism. Hence, the objective of this review is to present the most relevant findings of the b iology of H. Pylori and its interaction with the human host. The full versi on of this paper is available too at: http:// www.insp.mx/salud/index.html.