Author(s):
Oleastro, Mónica 
; Ménard, Armelle
Date: 2013
Persistent ID: http://hdl.handle.net/10400.18/2174
Origin: Repositório Científico do Instituto Nacional de Saúde
Subject(s): Helicobacter Pylori; Outer Membrane Proteins; Pathogenesis; Bacterial Adherence; Infecções Gastrointestinais
Description
Helicobacter pylori is one of the most successful human pathogens, whichcolonizes the mucus layer of the gastric epithelium of more than 50% of the world’spopulation. This curved, microaerophilic, Gram-negative bacterium induces a chronicactive gastritis, often asymptomatic, in all infected individuals. In some cases, this gastritisevolves to more severe diseases such as peptic ulcer disease, gastric adenocarcinoma, andgastric mucosa-associated lymphoid tissue lymphoma. H. pylori has developed a unique setof factors, actively supporting its successful survival and persistence in its natural hostileecological niche, the human stomach, throughout the individual’s life, unless treated. In thehuman stomach, the vast majority of H. pylori cells are motile in the mucus layer lining,but a small percentage adheres to the epithelial cell surfaces. Adherence to the gastricepithelium is important for the ability of H. pylori to cause disease because this intimateattachment facilitates: (1) colonization and persistence, by preventing the bacteria frombeing eliminated from the stomach, by mucus turnover and gastric peristalsis; (2) evasionfrom the human immune system and (3) efficient delivery of proteins into the gastric cell,such as the CagA oncoprotein. Therefore, bacteria with better adherence propertiescolonize the host at higher densities. H. pylori is one of the most genetically diversebacterial species known and is equipped with an extraordinarily large set of outermembrane proteins, whose role in the infection and persistence process will be discussed in this review, as well as the different receptor structures that have been so far described for mucosal adherence.
