Prevalence and genetic diversity of cagD, cagE, and vacA in Helicobacter pylori strains isolated from Japanese patients

Background: Although cagD and cagE (cagDE) identified upstream of cagA have been shown to be involved in the induction of interleukin (IL)-8 expressio n, the relationship between cagDE status and gastroduodenal diseases still remains to be examined. Thus we investigated prevalence and genetic diversi ty of cagD, cagE, and vacA in Helicobacter pylori strains isolated from pat ients with peptic ulcer or gastritis. Methods: We analyzed 73 H. pylori str ains isolated from Japanese patients (gastritis (GA), 15; gastric ulcer (GU ), 28; duodenal ulcer (DU), 23; GU and DU, 7). The presence of cagDE was ev aluated by polymerase chain reaction (PCR) and Southern hybridization. The vacA genotype was examined by PCR, using type-specific primers. Results: ca gDE was present in 13 (86.7%) of 15 patients with GA, 26 (92.9%) of 28 pati ents with GU, 21 (91.3%) of 23 patients with DU, and 6 (85.7%) of 7 patient s with GU and DU (P = 0.89). vacA signal sequence type sl was found in 14 ( 93.3%) of 15 patients with GA, 26 (92.9%) of 28 patients with GU, 22 (95.7% ) of 23 patients with DU, and 6 (85.7%) of 7 patients with GU and DU (P = 0 .84). Sequences of cagDE and vacA in our Japanese strains were highly homol ogous with one another, and there were no disease-specific mutations. Concl usions: Most of the H. pylori strains in Japan were cagDE-positive, vacA sl type, regardless of clinical outcome. The present study also indicated tha t these genes were conserved well among our H. pylori isolates.