BACKGROUND Failure of Helicobacter pylori (H. pylori) eradication is principally caused by antimicrobial resistance. Nowadays, multidrug resistance could be a major determinant of eradication failure. To assess minimal inhibitory concentration (MIC), antimicrobial resistance rates and trends in H. pylori isolated from patients with upper gastrointestinal disease with long-term period.

MATERIALS AND METHODS Patients who had H. pylori colonies isolated from culture were consecutively enrolled during the period of 2003-2022. From each patient, one to ten isolates were collected from culture of mucosal biopsy. MIC test was performed for amoxicillin, clarithromycin, metronidazole, tetracycline, levofloxacin, and moxifloxacin using agar dilution method. Trends in MIC distribution, prevalence of resistances with single and multiple were investigated which were suspected to be related to the failure of empirical H. pylori eradication treatment.

RESULTS From 2003 to 2022, a total of 873 patients were enrolled and 2735 H. pylori isolates were successfully collected. Increase in the primary resistance rate was found in clarithromycin (16.1%-31.0%, p = .022), metronidazole (30.6%-38.1%, p < 0.001), and both of levofloxacin and moxifloxacin (7.3%-35.7%, p < 0.001). The prevalence of multidrug resistance to both clarithromycin and metronidazole (9.2%-37.9%, p < 0.001), clarithromycin and fluoroquinolone (2.8%-41.7%, p < 0.001), and clarithromycin, metronidazole, and fluoroquinolone (1.4%-28.2%, p < 0.001) was found to significantly increase.

CONCLUSIONS The prevalence of multiple resistance against H. pylori in Korea is ongoing. Its trend should be considered when establishing an empirical treatment strategy (ClinicalTrials. gov: NCT05247112).