PANMICTIC STRUCTURE OF HELICOBACTER-PYLORI DEMONSTRATED BY THE COMPARATIVE-STUDY OF 6 GENETIC-MARKERS

We compared the classifications of strains obtained by analysis of sev eral genetic markers to demonstrate the panmictic structure of Helicob acter pylori, previously suggested by the study of multilocus enzyme e lectrophoresis. A series of 39 strains, including 37 clinical isolates from patients with gastritis or ulcers from two regions of France, re ference strain CIP 101260 and the Sydney strain (strain SSI), were use d. They were studied by restriction fragment length polymorphism analy sis of ribosomal DNA (ribotyping) using HindIII and HaeIII, by polymor phism analysis of the ureA-ureB and flaA genes by PCR-RFLP using HaeII I and MboI. by vacA genotyping and by the presence or absence of the c agA gene and of the insertion sequence IS605 detected by PCR. There wa s a high level of genetic polymorphism over the studied strains, with 38 ribotypes, 38 restriction profiles for the ureA-ureB gene, 19 restr iction profiles for the flaA gene and five combinations of the signal and mid-region sequences of the vacA gene. Factorial analysis of corre spondence and hierarchical clustering performed using each marker reve aled that the different classifications of the strains were not correl ated. This suggests there is much genetic recombination between strain s and supports the hypothesis of a panmictic structure for the H. pylo ri species. (C) 1998 Federation of European Microbiological Societies. Published by Elsevier Science B.V.