The etiologic link between H. pylori infection and gastric chronic inflammation and related complications has been well established, but pathogenic pathways are still widely discussed and not sufficiently clear. The introduction of culture-independent molecular techniques has allowed better understanding of the gastric microbiota and has revealed that, when present, H. pylori represents the main colonizer but is part of a far more complex and dynamic microbiota than previously thought. This conceptual shift has made way for new pathogenic theories, focused on the interrelations between H. pylori and other gastric microbiota. Main factors that affect the gastric microbiota are gastric acidity, inflammation, and environmental factors, such as diet and drugs. Previous studies have made progress in explaining the complex interactions between gastric microorganisms in healthy individuals and their role in the development of related gastroduodenal (peptic ulcers and gastric cancer (GC)) and extraintestinal diseases, but more scientific proof is needed. This review presents current knowledge on gastric microbiota and its role in health and in the development of gastroduodenal diseases.
Part of the book: Gastrointestinal Stomas