Evaluation of CO₂ Condition for Antibiotic Susceptibility Test of Helicobacter pylori on Microdilution Broth

Abstract

We determined the MICs of clarithromycin for 32 Helicobacter pylori strains isolated from gastric mucosa of patients, by using microdilution broth method under different microaerobic conditions (CO₂: 5% and 15%). The pH of broth was more acidic at 15% CO₂than that of at 5% CO₂. The MICs of clarithromycin for all H. pylori strains at15% CO₂ condition werehigher than that of clarithromycin at 5% CO₂, condition. Comparing the MICs with the results of eradication therapy, we concluded that the measurment of MIC under 5% CO₂, condition is more useful for expecting the clinical outcome.