Isolation of dupA-positive and clarithromycin-resistant Helicobacter pylori from Iranian patients with duodenal ulcer

Abstract

BackgroundEmergence of the antibiotic-resistant Helicobacter pylori strains has compelled the development of novel and complex therapeutic approaches. The duodenal-ulcer-promoting gene A (dupA), a virulence factor of H. pylori, is thought to be associated with a high risk of duodenal ulcerations but not gastric cancer. We propose that the association between clarithromycin resistance and presence of dupA may help clinicians formulate better therapeutic regimens. MethodsWe thus investigated H. pylori colonization in 90 patients, including 27 with gastritis, 40 with duodenal ulcer, and 23 with gastric cancer. We used the E-test for determining the minimal inhibitory concentrations of clarithromycin according to standard protocols. Bacterial culturing and glmM-specific PCR were used to determine the prevalence of the relevant H. pylori strains. ResultsdupA-Positive strains were not equally distributed among the three disease groups (gastritis 32.5%; duodenal ulcer 62.9%; gastric cancer 21.7%). We found a significant association between dupA-positive H. pylori strains and duodenal ulcer (P = 0.02; OR: 2.67; 0.95 CI: 1.09–6.49). We assessed the susceptibility to clarithromycin of the H. pylori isolates. Clarithromycin resistance was prevalent in 47% of the isolates. The dupA-positive H. pylori strains were more resistant to clarithromycin (P = 0.013; OR: 3.12; 0.95 CI: 1.20–8.11) than other strains. ConclusionWe conclude that dupA presence may be a marker for clarithromycin-resistant H. pylori strains among the patients with duodenal ulcer.