Published online Oct 7, 2019. doi: 10.3748/wjg.v25.i37.5578
Peer-review started: June 17, 2019
First decision: July 21, 2019
Revised: August 14, 2019
Accepted: August 19, 2019
Article in press: July 21, 2019
Published online: October 7, 2019
Helicobacter pylori (H. pylori) is a gram-negative bacterium that infects approximately 4.4 billion individuals worldwide. However, its prevalence varies among different geographic areas, and is influenced by several factors. The infection can be acquired by means of oral-oral or fecal-oral transmission, and the pathogen possesses various mechanisms that improve its capacity of mobility, adherence and manipulation of the gastric microenvironment, making possible the colonization of an organ with a highly acidic lumen. In addition, H. pylori presents a large variety of virulence factors that improve its pathogenicity, of which we highlight cytotoxin associated antigen A, vacuolating cytotoxin, duodenal ulcer promoting gene A protein, outer inflammatory protein and gamma-glutamyl transpeptidase. The host immune system, mainly by means of a Th1-polarized response, also plays a crucial role in the infection course. Although most H. pylori-positive individuals remain asymptomatic, the infection predisposes the development of various clinical conditions as peptic ulcers, gastric adenocarcinomas and mucosa-associated lymphoid tissue lymphomas. Invasive and non-invasive diagnostic methods, each of them with their related advantages and limitations, have been applied in H. pylori detection. Moreover, bacterial resistance to antimicrobial therapy is a major challenge in the treatment of this infection, and new therapy alternatives are being tested to improve H. pylori eradication. Last but not least, the development of effective vaccines against H. pylori infection have been the aim of several research studies.
Core tip:Helicobacter pylori (H. pylori) is a bacterium that infects more than half of the world’s population. The mechanisms of such infections are complex and deeply studied. In addition, the clinical outcomes are variable and depend on both pathogen and host characteristics. Moreover, the adequate clinical management by means of proper diagnosis and effective treatment is crucial for reaching success in bacterial eradication. This article aims to provide a broad overview of H. pylori infection, from pathogenesis to clinical management.