The effect of previous eradication failure on antibiotic resistance of Helicobacter pylori: A retrospective study over 8 years in Beijing.

Background: Antibiotic resistance is the main cause of Helicobacter pylori (H. pylori) treatment failure. This study aimed to explore the characteristics of antibiotic resistance of H. pylori isolates in Beijing in the last 8 years and to estimate the impact of previous eradication failure on resistance patterns. Materials and methods: This retrospective study included data from a single center in Beijing from 2013 to 2020. Antibiotic susceptibility of 365 clinical H. pylori isolates was tested for amoxicillin, clarithromycin, metronidazole, levofloxacin, moxifloxacin, and tetracycline. The characteristics of the included patients and their previous eradication history were collected. Primary and secondary resistance rates of H. pylori to the six antibiotics and the impact of previous eradication failure on antibiotic resistance patterns were analyzed. Results: The overall primary resistance rates of amoxicillin, clarithromycin, metronidazole, levofloxacin, moxifloxacin, and tetracycline were 0.7%, 55.2%, 68.0%, 49.7%, 64.5%, and 0%, with no significant increase during the observed period; while the secondary resistance rates were 3.2%, 96.7%, 90.7%, 93.1%, 80.0%, and 0%, respectively. The secondary resistance rate of clarithromycin (p <.001), metronidazole (p =.001), and levofloxacin (p <.001) significantly increased to 100% as the number of previous eradication therapies increased and exhibited a linear association. For strains naive to eradication, only 6.8% were susceptible to all the antibiotics, while 32.4% were single resistant, and 60.8% dual or multiple resistant. Clarithromycin+metronidazole+fluoroquinolone multiple resistance was the predominant pattern (0 course: 21.6%, 1 course: 37.5%, 2 courses: 56.1%, ≥3 courses: 71.1%; p <.001) for patients with treatment failure. The prevalence of dual or multiple‐resistance patterns increased significantly as the number of previous therapies increased. Conclusions: The prevalence of primary and secondary resistance rates of clarithromycin, metronidazole, moxifloxacin, and levofloxacin were high in Beijing. Multiple‐resistance patterns were common after treatment failure. Resistance rates of amoxicillin and tetracycline remained low and stable. [ABSTRACT FROM AUTHOR]