A-329 Clarithromycin Resistance rates of Helicobacter pylori infected gastric biopsies in Korea

Background The macrolide clarithromycin has emerged as the most important antibiotic in combined therapy for eradication of Helicobacter pylori (H. pylori) infection. The eradication of H. pylori has been shown to reduce the incidence of gastric cancer. However, concerns about increasing clarithromycin resistance in H. pylori and its impact on the efficacy of eradication therapy have been raised since its widespread acceptance in H. pylori therapy. The global clarithromycin resistance rates are various among patient groups according to sex, age and geographic location. There are a few research analyzing specimens from local clinics and hospitals using molecular methods. Here, we sought to assess the clarithromycin resistance rates across sex, age groups as well as to explore regional variation in korea. Methods We collected 4040 gastric biopsies or tissue from 50 local clinics or hopsitals for molecular detection of H. pylori and clarithromycin resistance rate using 23s ribosomal RNA genes from Jan 2022 to Oct 2024. We analyzed the prevalence of clarithromycin resistance rates and investigated the patient*s age, sex, and regional distribution in Korea for the A2042G and A2043G mutations related to clarithromycin resistance. Results Clarithromycin resistance rate accounted for 32.4% of the total 4,040 patients, with 40.1% in women and 25.7% in men. Among the mutation types, A2143G showed a higher frequency than A2142G in both men and women. The resistance rate was higher in women than in men. In particular, the resistance rate showing the A2143G mutation in women increased every year. The clarithromycin resistance rate by age showed that the frequency of the A2143G mutation in women was over 40% in their 40s and 70s, and the mutation in A2142G gradually increased with age. In men, the frequency of the A2143G mutation was over 30% in the 20s and 80s and older. All five patients in their teens showed the A2143G mutation. Regional clarithromycin resistance rates showed a frequency of over 40% in Kyungsang, Seoul, and Chungcheong in women, and a frequency of over 40% in Pusan and Kyungsang in men. Conclusion In Korea, the clarithromycin resistance rate of Helicobacter pylori found in gastric tissues in men and women from 2022 to 2024 showed a high frequency of 32.4% on average. The mutation frequency was higher in women than in men, and the A2143G mutation showed a higher frequency than the A2142G mutation. In particular, the frequency of A2142G in women tended to increase every year. The frequency showed differences by age and region. When treating Helicobacter pylori, it is necessary to pay attention to the treatment outcome and the occurrence of resistance by referring to the clarithromycin resistance rate.