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

Abstract

Background: Emergence 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. Methods: We 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. Results: dupA-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. Conclusion: We conclude that dupA presence may be a marker for clarithromycin-resistant H. pylori strains among the patients with duodenal ulcer. Show more