Helicobacter Pylori infection: A review

INTRODUCTION Helicobacter pylori (H. pylori) a spiral-shaped, Gram negative bacterium found on the luminal surface of the gastric epithelium, was first isolated in 1983 (1). H. pylori infection is the most common chronic human bacterial infection (2). Its prevalence increases with lower socioeconomic class and older age, so its geographic distribution is markedly variable (3). H. pylori infects more than 50% of the world’s adult population. In Iran, 80% of adult population are infected by H. pylori, however, only 5-10% have developed peptic ulcer disease (PUD) or much more rarely gastric mucosa – associated lymphoid tissue (MALT) lymphoma (4). In contrast to developed countries, H. pylori infection usually acquired during childhood, by the age of 5 years, in developing countries (5). H. pylori has the ability to survive within acid environment of stomach (6). Its infection recurrence is a common problem after eradication, which may be due to an infectious source in gastrointestinal tract (7).