For Helicobacter pylori infections, proton pump inhibitor (PPI)-based triple regimens with clarithromycin are not recommended in areas where clarithromycin resistance is more than 15% or in patients who have previously taken macrolides. Up-to-date information on local resistance patterns is scarce, especially in the US. The present study reports resistance rates to antibiotics commonly used to treat H. pylori from a large study conducted in the US and Europe (pHalcon-HP).

The study collected Gastric mucosal biopsies from adult participants with H. pylori infection during screening. It determined Minimum inhibitory concentrations via agar dilution for clarithromycin, amoxicillin, and metronidazole, with breakpoints ≥1 µg/mL, >0.125 µg/mL, and >8 µg/mL, respectively. It obtained resistance rates for the US and Europe and also for US subregions and participating European countries.

The study observed-

• It established Resistance rates in isolates from 907 participants.
• 22.2% were resistant to clarithromycin, 1.2% to amoxicillin, and 69.2% to metronidazole.
• Similar Resistance in the US and Europe
• The most prevalent resistance was from metronidazole (50-79%), while the least was from amoxicillin (≤5%).
• All subregions, except the UK, showed resistance to clarithromycin in ≥15% of isolates.
• Among clarithromycin-resistant isolates, 75% were also metronidazole-resistant.
• Among two US isolates resistant to clarithromycin and amoxicillin, one was also metronidazole-resistant.

This study shows the resistance rates that disfavor the continued empiric use of PPI-based triple therapy containing clarithromycin, per treatment guidelines, and highlights the need for antibiotic resistance surveillance and novel treatment strategies for H. pylori infection in the US and Europe.

Am J Gastroenterol. 2022 Sep 30. doi: 10.14309/ajg.0000000000002045. Epub ahead of print. PMID: 36191284.