MULTIPLE STRAIN COLONIZATION AND METRONIDAZOLE RESISTANCE IN HELICOBACTER PYLORI-INFECTED PATIENTS - IDENTIFICATION FROM SEQUENTIAL AND MULTIPLE BIOPSY SPECIMENS

Helicobacter pylori strain diversity was investigated in infected pers ons by collection of multiple biopsies before and after therapy failur e. It was demonstrated by random amplification of polymorphic DNA poly merase chain reaction that patients may be infected with a mixed popul ation of H. pylori strains. Most patients were colonized with a predom inant strain accompanied by up to 5 variant strains. The use of antimi crobials resulted in an altered distribution of the strains present, b ut the predominant strain usually remained. Patients may be infected w ith a mixed population of metronidazole-sensitive and -resistant strai ns at one time, with metronidazole-based therapy selectively enriching for a resistant population.