RESUMO
Helicobacter pylori is a major etiological agent in gastro-duodenal disorders, and has spread in the world. The prevalence of infection with H. pylori is more than 80% in some populations, but only 10% to 20% of them are infected with this organism. Also infection with this pathogen is associated with peptic ulcer disease [PUD], Gastritis [G], Duodenitis [Du], and non-ulcer dyspepsia [NUD]. The development of diseases depends on the virulence of the infecting H. pylori strain and the susceptibility of the host. The vacuolating cytotoxin and the cytotoxin associated protein, encoded by vacA and cagA genes are important virulence determinants of H. pylori which are divided into different pathogenic types, to cause varities of infections. This may be used as a marker of infection and could be used to distinguish between pathogenic and nonpathogenic strains of H. pylori in Iran. The aim of this study was to assess the prevalence of vacA genotype of H. pylori and its development of PUD, G, Du, and NUD from Iranian patients who were admitted to Hazrat Rasoul Akram [peace upon him] as an educational and research society, affiliated to Iran University of Medical Sciences and Health Services [IUMS] in Tehran, Iran. During this study specimen biopsies were collected from 180 patients who underwent routine gastrointestinal endoscopies to the internal medicine ward, Hazrat Rasoul Akram Hospita, LIUMS, Tehran, Iran. Positive H. pylori strains were identified by cultured isolates, standard biochemical methods, and molecular typing was performed by PCR technique to detect vacA gene and its alleles. In this study out of 180 samples of 93 H. pylori strains were isolated and identified by biochemical tests, the PUD, G, Du and NUD were 79%, 60%, 90% and 30% respectively. 87 [94%] strains contained vacA gene and the predominant genotypes are in the vacA gene. Also 59 [64%] strains had displayed the sl/m2 genotype. 57 [625] strains were classified as type 1, 31[33%] strains were type IV, 3 [3.26%] strains were type II, and 2[2.17% strains were type III. The significant difference [P<0.01] between type I and type IV isolated strains from PUD [62% type I] showed that type I strains are more pathogenic than type IV strains