Emergence of amoxicillin resistance in refractory Helicobacter pylori infection

This study investigated temporal changes in resistance patterns among treatment-refractory Helicobacter pylori infections in Taiwan.

Antibiotic resistance in H. pylori is a growing global concern.

We retrospectively analyzed adult patients at Linkou Chang Gung Memorial Hospital (2018-2024) with ⩾2 prior eradication failures and confirmed active infection via [13C]-urea breath test.

Gastric biopsy specimens were cultured, and antimicrobial susceptibility testing was performed using the Epsilometer test for amoxicillin, clarithromycin, metronidazole, levofloxacin, tetracycline, rifabutin, ciprofloxacin, and moxifloxacin. Breakpoints were defined according to the European Committee on Antimicrobial Susceptibility Testing.

Among 144 patients (mean age 57.1 ± 10.8 years; 27.8% male), 88 were culture positive (61.1%), yielding 109 isolates. Resistance rates were high for clarithromycin (89.9%), levofloxacin (86.2%), metronidazole (71.6%), and ciprofloxacin (87.2%), while tetracycline resistance was 15.6%. A temporal trend analysis revealed a marked and statistically significant increase in amoxicillin resistance (odds ratio per year, 1.60; 95% confidence interval, 1.31-1.96; p < 0.001), while resistance to other key antimicrobials remained persistently high but stable.

In refractory H. pylori infection, there is persistently high resistance to clarithromycin, fluoroquinolones, and metronidazole, with a notable surge in amoxicillin resistance. These findings underscore the need for strengthened antimicrobial stewardship and reconsideration of empiric treatment strategies in high-resistance regions.