PCR-RFLP typing of ureC from Helicobacter pylori isolated from gastric biopsies during a European multi-country clinical trial

Abstract

A multi-country clinical trial was conducted in ten European countries to determine the efficacy of clarithromycin-omeprazole dual therapy for treating Helicobacter pylori infection in peptic ulcers. Gastric biopsies were cultured for H. pylori before and after treatment. PCR-RFLP was used to determine the genetic heterogeneity of 100 H. pylori isolates from pretreatment and posttreatment biopsies. An 820 bp amplified fragment of the ureC gene was digested with the restriction enzymes Sau3A and Hhal. Fourteen different Sau3A patterns and isolates. In combination, 42 different RFLP types were identified. Comparison of isolates before treatment with those after treatment showed that five of ten patients on clarithromycin-omeprazole dual therapy had the same RFLP type and that all 12 patients on omeprazole therapy alone had the same RFLP type. All isolates were susceptible to clarithromycin prior to treatment, while seven of ten patients on clarithromycin-omeprazole therapy had H. pylori that was resistant to clarithromycin after therapy and 11 of 12 patients on omeprazole therapy had isolates susceptible to clarithromycin after treatment. In addition to PCR-RFLP typing, the presence of the cytotoxin-associated gene (cagA) and the vacuolating gene (vacA) was determined; 79% of the isolates were cagA-positive and all were vacA-positive. The results of this study indicate that infection of H. pylori in Europe is not restricted to a few RFLP types.