COMPARISON OF PCR-BASED RESTRICTION LENGTH POLYMORPHISM ANALYSIS OF UREASE GENES WITH RIBOSOMAL-RNA GENE PROFILING FOR MONITORING HELICOBACTER-PYLORI INFECTIONS IN PATIENTS ON TRIPLE THERAPY

Multiple isolates of Helicobacter pylori from antral biopsies of nine patients were examined by DNA fingerprinting. Analysis of rRNA gene pa tterns and HaeIII restriction fragment length polymorphism of PCR-ampl ified urease genes were compared and used to study colonization before and after failed triple therapy. H. pylori isolates from a single bio psy shared the same Haem DNA fingerprint regardless of the isolation m ethod (plate or broth). DNA pattern types of paired strains of H. pylo ri were distinct between patients and were not grossly affected by tre atment except for one patient with an altered strain type. H. pylori i nfections were generally associated with several subpopulations of str ains, evident from the subtypic variation before and after treatment, detectable by both DNA fingerprinting methods. The urease gene pattern s also provided evidence that some cultures of H. pylori probably cont ained a mixture of genomic subtypes. The study suggests that triple th erapy has the effect either of inducing minor genomic variations or of changing the proportions of different subtypes of H. pylori. It was c oncluded that urease gene profiling provides a simple get reliable met hod of establishing whether treatment failures are attributable to inc omplete eradication of H. pylori.