The bactericidal activity of clarithromycin versus ampicillin alone and in combination with omeprazole and/or bismuth against clarithromycin-susceptible and. Clarithromycin-resistant strains of Helicobacter pylori

We evaluated the in vitro bactericidal effect of clarithromycin versus ampicillin alone and in combination against clarithromycin-sensitive and clarithromycin-resistant strains of Helicobacter pylori. No combination containing clarithromycin achieved complete bactericidal effect against clarithromycin-resistant strains. Complete bactericidal effect ions achieved for all strains by triple-agent combinations that contained bismuth, omeprazole, and relatively high concentrations of ampicillin. These in vitro results demonstrate the additive bactericidal activity provided by a combination of agents for the eradication of H, pylori. Bismuth may play a particularly important role in the bactericidal effect. (C) 1998 Elsevier Science Inc.