Helicobacter pylori culture positivity and antimicrobial susceptibility profiles (Vancouver, Canada)

Helicobacter pylori is associated with gastrointestinal diseases including gastritis and peptic ulcers. Despite its significance, there is a scarcity of antimicrobial susceptibility testing (AST) data available for this organism in North America.

The aim of this study was to assess the AST profile and identify factors associated with H. pylori culture positivity in a cohort of patients with refractory H. pylori undergoing gastric biopsies.

We retrospectively reviewed gastric biopsy specimens received for culture between July 2009 and February 2023. We analyzed specimen transport time, Gram smear results, direct urease test findings, culture positivity and AST profiles. Using gradient strip methodology and European Committee on Antimicrobial Susceptibility Testing breakpoints, AST was conducted for amoxicillin, clarithromycin, metronidazole, levofloxacin and tetracycline.

Of 579 biopsy samples received for H. pylori culture, 228 (39.4%) tested positive. Samples transported within <1 h had significantly higher odds (1.81 times, P < 0.015) of being culture positive compared to those with longer transport times. Smear-positive samples had substantially higher odds (18.8 times, P < 0.001) of culture positivity compared to smear-negative. Urease-positive samples demonstrated notably higher odds (7.7 times, P < 0.001) of culture positivity compared to urease-negative samples. The collection of isolates from gastric biopsies showed susceptibility rates of 97.3% to amoxicillin, 99.1% to tetracycline, 50.4% to levofloxacin, 25.9% to metronidazole and 12.9% to clarithromycin.

Short sample transport time was associated with improved H. pylori recovery rates. In this cohort of refractory H. pylori cases, susceptibility rates were high for amoxicillin and tetracycline and low for clarithromycin, metronidazole and levofloxacin. Susceptibility rates remained stable over time.