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

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.