INVITRO SUSCEPTIBILITY OF HELICOBACTER-PYLORI TO SEVERAL ANTIMICROBIAL COMBINATIONS

Synergy between metronidazole and its hydroxymetabolite and between ea ch compound and amoxicillin or tetracycline-HCl was determined against Helicobacter pylori. Metronidazole plus its hydroxymetabolite and eit her compound combined with amoxicillin showed synergism against all 10 strains of H. pylori tested. Metronidazole plus tetracycline-HCl or t he hydroxymetabolite plus tetracycline-HCl acted synergistically again st seven and six strains, respectively, acted additively against three strains, and had no additional effect against one strain. These resul ts may help to explain the in vivo efficacies of metronidazole combina tions in the treatment of H. pylori-associated gastritis.