Background: Clarithromycin resistance in Helicobacter pylori has been found to be associated with point mutations at positions 2142 and 2143 in 23SrRNA gene. The aims of this study were: (1) to determine the rates of point mutations A2143G, A2142G and A2142C in 23SrRNA gene of H. pylori among patients with chronic gastritis by PCR-RFLP technique; and (2) to assessthe association between these mutations and some clinical, endoscopic and histopathological characteristics of chronic gastritis. Patients and methods: two hundreds and twenty six patients with H. pylori-positive chronic gastritis were determined A2143G, A2142G and A2142C mutations by PCR-RFLP technique with DNA extracted from endoscopic biopsy specimens of gastric mucosa. Results: The rate of point mutations at positions 2142 and 2143 in 23S rRNA gene of H. pylori was 35.4% in total, the A2143G and A2142G mutationsaccounted for 92.5% and 7.5% of all point mutations, respectively. No A2142C mutation was found. These mutations were not associated with age, gender,distribution of gastritis, and the presence of atrophic gastritis. The rate of A2143G mutation in groups with and without a history of clarithromycin treatment were 44.9% and 24.8%, respectively (p = 0,0065). The A2142G mutation was associated with intestinal metaplasia and/or dysplasia. Conclusion: The point mutations at positions 2142 and 2143 in 23S rRNA gene were found at a high rate in H. pylori strains amongpatients with chronic gastritis, with the absolute predominance of A2143G mutation. The A2143G mutation was associated with a history of clarithromycin treatment. Key words: 23S rRNA gene, Helicobacter pylori, A2143G, A2142G, A2142C mutation, clarithromycin resistance, chronic gastritis.
Point mutations in the 23S rRNA gene of Helicobacter pylori associated with different levels of clarithromycin resistance
