Susceptibility of Helicobacter pylori to antimicrobial agents: effect of ebrotidine and ranitidine.

Convincing evidence now exists that infection with H. pylori is a primary factor in the pathogenesis of gastric disease, and new therapy regimens include a combination of H2 blockers with antimicrobial agents. In this study, was assessed the effect of ebrotidine and ranitidine on the in vitro anti-H. pylori activity of amoxicillin, erythromycin, tetracycline, and metronidazole. The assays of the antiulcer drugs alone gave MIC value of 150 mg/L for ebrotidine and 1600 mg/L for ranitidine. Inclusion of ebrotidine in the antimicrobial agent assays evoked at its optimal concentration of 75 mg/L a 28% enhancement in the MIC of metronidazole, 2.5-fold enhancement in the MIC of erythromycin, 2-fold in amoxicillin and 1.7-fold in tetracycline, while ranitidine caused noticeable changes in the MIC values of the tested antimicrobial agents only a the dose of 1600 mg/L. The results demonstrate that ebrotidine enhances anti-H. pylori activity of antimicrobial agents at doses well below that of ranitidine.