Zahra Nikbakht - Department of Microbiology, Tabriz Branch, Islamic Azad University, Tabriz, Iran
Javid Taghinejad - Department of Microbiology, Malekan Branch, Islamic Azad University, Malekan, Iran
Samaneh Kahkesh - Department of Biology, Faculty of Basic Sciences,Shahid Chamran University, Ahvaz, Iran

Helicobacter pylori is a type of spiral bacteria, but it can change into a spherical shape, which is also viable and pathogenic. This bacterium cannot be cultivated in a laboratory environment and attaches to the stomach mucosa. H.pylori is a gram-negative, curved and microaerophilic bacillus. Recently, this bacterium has been recognized as the main cause of chronic gastritis, peptic ulcers (both in the duodenum and stomach), adenocarcinoma and lymphoma of MALT cells. The infection caused by this bacterium has a global spread and can be seen in all age groups. It is estimated that about ۵۰% of the world's population is infected with this bacterium. Unlike developed countries, in developing countries, humans are infected with this bacteria in the early years of their lives, and the infection is caused through digestion by swallowing the bacteria. Also, there is a possibility of person-to-person transmission of H.pylori, because the spread of infection occurs through family members. However, the most important mode of transmission is through water. Identification of H.pylori as one of the main causes of gastrointestinal ulcers is very important in prognosis and treatment. Many direct and indirect tests are used in the diagnosis of H.pylori. The diagnostic sensitivity of serological methods is higher than other biochemical methods. With effective antimicrobial treatment, the antibody titer decreases.

Helicobacter pylori, morphology, diagnostic methods, immunology, serology