Frequency of Helicobacter pylori vacA genotypes in Iranian patients with gastric and duodenal ulcer.

Helicobacter pylori infection is a risk factor for developing chronic peptic ulcers and gastric cancer. The purpose of this study was to investigate the frequency of Helicobacter pylori vacA genotypes in patients with gastric and duodenal ulcer. A total of 100 biopsy specimens of patients with gastric (n=50) and duodenal (n=50) ulcer were collected. The specimens were cultured on selective media and incubated in a microaerophilic atmosphere at 37 degrees C for 5-10 days. The isolates were characterized to species level by conventional biochemical tests. The extracted DNA from isolates was used to perform a polymerase chain reaction based, simultaneous analysis of the cagA status, allelic variation of the signal regions (s1, s2) and the middle regions (m1, m2) of the vacA gene. H. pylori isolated from 50 specimens of patients and the vacA gene was detected in all isolates. Among vacA genotypes the s1/m1 was the most common in H. pylori isolates from patients with gastric ulcer (56%) and duodenal ulcer (68%). This study demonstrated that vacA slml is common genotype of H. pylori in patients with peptic ulcer and the vacA allele s1 of this bacterium is associated with ulcer.