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World J Gastroenterol. May 21, 2014; 20(19): 5610-5624
Published online May 21, 2014. doi: 10.3748/wjg.v20.i19.5610
Factors that mediate colonization of the human stomach by Helicobacter pylori
Ciara Dunne, Brendan Dolan, Marguerite Clyne
Ciara Dunne, Brendan Dolan, Marguerite Clyne, School of Medicine and Medical Science and Conway Institute of Biomedical and Biomolecular Science, University College Dublin, Belfield, Dublin 4, Ireland
Author contributions: Dunne C, Dolan B and Clyne M performed the research, analyzed the data, and wrote the paper.
Supported by A post graduate student grant awarded by Irish Research Council for Science Engineering and Technology (To Dunne C); an award from the Health Research Board Ireland; and a grant from Science Foundation Ireland, No. 08/SRC/B1393
Correspondence to: Marguerite Clyne, PhD, School of Medicine and Medical Science and Conway Institute of Biomedical and Biomolecular Science, University College Dublin, Belfield, Dublin 4, Ireland. marguerite.clyne@ucd.ie
Telephone: +353-1-7166619 Fax: +353-1-7166619
Received: October 25, 2013
Revised: December 4, 2013
Accepted: January 19, 2014
Published online: May 21, 2014
Abstract

Helicobacter pylori (H. pylori) colonizes the stomach of humans and causes chronic infection. The majority of bacteria live in the mucus layer overlying the gastric epithelial cells and only a small proportion of bacteria are found interacting with the epithelial cells. The bacteria living in the gastric mucus may act as a reservoir of infection for the underlying cells which is essential for the development of disease. Colonization of gastric mucus is likely to be key to the establishment of chronic infection. How H. pylori manages to colonise and survive in the hostile environment of the human stomach and avoid removal by mucus flow and killing by gastric acid is the subject of this review. We also discuss how bacterial and host factors may together go some way to explaining the susceptibility to colonization and the outcome of infection in different individuals. H. pylori infection of the gastric mucosa has become a paradigm for chronic infection. Understanding of why H. pylori is such a successful pathogen may help us understand how other bacterial species colonise mucosal surfaces and cause disease.

Keywords: Helicobacter pylori, Colonization, Infection, Gastric mucosa, Urease, Flagella, Polymorphisms, Adhesins, CagA, Type IV secretion system

Core tip: Colonization of gastric mucus by Helicobacter pylori (H. pylori) key to the establishment of chronic infection. How H. pylori manages to colonise and survive in the hostile environment of the human stomach and avoid removal by “mucus flow” and killing by gastric acid is the subject of this review. We also discuss how bacterial and host factors may together go some way to explaining the susceptibility to colonization and the outcome of infection in different individuals. Understanding of how H. pylori causes chronic infection will likely serve as a valuable reference system for how other bacteria colonise mucosal surfaces.