Investigation of cagI and cagII in H. pylori Isolated from Dyspepsia Patients in Iran

Abstract

Background: The major virulence factor of H. pylori is the cag pathogenicity island divided into two parts: the upstream cagII region and the downstream cagI region. The downstream region includes cagA, cagE, and themost important gene introduced in cagII is cagT. The aim of this study was to investigate the important markers of cagI and cagII regions in Helicobacter pylori isolated from Iranian peptic ulcer and non ulcer disease patients. Methods and materials: 80 clinical isolates of H. pyloriwere collected from 120 patients with gastric disorders. The genomic DNA was extracted from biopsy samples by the QIAgen kit. The PCR was performed for detection of cagA, cagE and cagT in cagPAI. Results: Among 80 H. pylori strains, 20 (25%) and 60 (75%) were isolated from PUD and NUD patients respectively. In PUD patients with rate of 14 (70%), all of isolates were cagA positive and distribution of cagE was 7 (35%) and cagT was 5 (25%). Also the prevalence of cagA, cagE and cagT in NUD patients was 48 (80%), 21 (35%) and 22 (36%) respectively. Discussion: Our results indicated that presence of cag PAI is very common in Iranian strains of H. pylori. The structural variety of the cag PAI might be related to the virulence of H. pylori. Present study showed that the prevalence of cagT, a marker for cagII, in PUD patients is less than NUD patients. In cagI region the presence of cagA in PUD patient is higher than cagE, so it may have an important role in peptic ulcer disease. According to our results it seems that it is not absolutely necessary to coexist of cagII and cagI in peptic ulcer patients.