Association among H. pylori virulence markers dupA, cagA and vacAin Brazilian patients

Abstract

Background: Only a fewHelicobacter pylori-infected individuals develop severe gastric diseases and virulence factors ofH. pyloriappear to be involved in such clinical outcomes. Duodenal ulcer promoting gene A (dupA) is a novel virulence factor ofHelicobacter pylorithat is associated with duodenal ulcer development and reduced risk for gastric carcinoma in some populations. The aims of the present study were to determine the presence ofdupAgene and evaluate the association amongdupAand other virulence factors includingcagAandvacAin Brazilian patients. Gastric biopsies were obtained from 205 dyspeptic patients (100 children and 105 adults). DNA was extracted and analyzed for the presence ofH. pyloriand its virulence factors using the polymerase chain reaction method.Results: Patients with gastritis tested positive forH. pylorimore frequently. ThedupAgene was detected in 41.5% of them (85/205);cagAgene was found in 98 isolates (47.8%) andvacAgenotype s1/m1 in 50.2%, s1/m2 in 8.3%, s2/m2 in 36.6%, s2/m1 in 0.5% and s1/s2/m1/m2 in 4.4%. We also verified a significant association betweencagAanddupAgenes [p = 0.0003, relative risk (RR) 1.73 and confidence interval [CI] = 1.3-2.3]. The genotypes s1/m1 were also associated withdupAgene (p = 0.0001, RR: 1.72 and CI: 1.3-2.2). The same associations were found when analyzing pediatric and adult groups of patients individually.Conclusion: Ours results suggest thatdupAis highly frequent in Brazilian patients and is associated withcagAgene andvacAs1/m1 genotype, and it may be considered an important virulence factor in the development of gastric diseases in adults or children.