Ribotyping patterns and emergence of metronidazole resistance in paired clinical samples of Helicobacter pylori.

Metronidazole-susceptible pretreatment isolates and metronidazole-resistant posttreatment isolates of Helicobacter pylori from 11 patients before and after unsuccessful triple therapy consisting of metronidazole, amoxicillin, and colloidal bismuth subcitrate were studied. Ribotyping (rRNA gene restriction pattern analysis) of the isolates demonstrated that all patients except one had identical digest patterns for pre- and posttreatment isolates.