Distribution of Helicobacter pylori virulence markers in patients with gastroduodenal diseases in a region at high risk of gastric cancer.

Abstract Abstract background Helicobacter pylori (H. pylori) is a major human pathogen that is responsible for various gastroduodenal diseases. We investigated the prevalence of H. pylori virulence markers in a region at high risk of gastric cancer. Methods One hundred and sixteen H. pylori strains were isolated from patients with gastroduodenal diseases. cagA , the cagA 3′ variable region, cag PAI genes, vacA , and dupA genotypes were determined by PCR, and some amplicons of the cagA 3′ variable region, cag PAI genes and dupA were sequenced. Results cagA was detected in all strains. The cagA 3′ variable region of 85 strains (73.3%) was amplified, and the sequences of 24 strains were obtained including 22 strains possessing the East Asian-type. The partial cag PAI presented at a higher frequency in chronic gastritis (44.4%) than that of the severe clinical outcomes (9.7%, p vacA genotypes were s1a/m2 (48.3%) and s1c/m2 (13.8%). Thirty-six strains (31.0%) possessed dupA and sequencing of dupA revealed an ORF of 2449-bp. The prevalence of dupA was significantly higher in strains from patients with the severe clinical outcomes (40.3%) than that from chronic gastritis (20.4%, p  = 0.02). Conclusion The high rate of East Asian-type cagA , intact cag PAI, virulent vacA genotypes, and the intact long-type dupA may underlie the high risk of gastric cancer in the region.