GENETIC AND PHENOTYPIC ANALYSIS OF BORRELIA-VALAISIANA SP. NOV. (BORRELIA GENOMIC GROUPS VS116 AND M19)

To clarify the taxonomic status of two recently described Borrelia gen omic groups, groups VS116 and M19, three group VS116 strains and eight group M19 strains isolated from Ixodes ricinus ticks in Switzerland, The Netherlands, and the United Kingdom were characterized. PCR-restri ction fragment length polymorphism (RFLP) analysis of the 5S-23S inter genic spacer amplicon, rRNA gene restriction analysis, 16S rRNA gene s equence analysis, randomly amplified polymorphic DNA (RAPD) fingerprin ting, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-P AGE), and immunoblotting with monoclonal antibodies were used for gene tic and phenotypic analysis, The PCR-RFLP and RAPD patterns of three g roup VS116 strains snarl eight group M19 strains were identical but di ffered from those of Borrelia burgdorferi sensu stricto, Borrelia gari nii, Borrelia afzelii, and Borrelia japonica. DNAs from all group VS11 6 and M19 strains yielded three fragments (6.9, 3.2, and 1.4 kb) and f our fragments (2.1, 1.2, 0.8, and 0.6 kb) after digestion with EcoRV a nd HindIII, respectively, hybridizing with an Escherichia coli 16S+23S cDNA probe. The SDS-PAGE protein profiles of group VS116 and M19 stra ins were heterogeneous, Phylogenetic analysis of the partial 16S rRNA gene sequences showed that group VS116 and M19 spirochetes were member s of a Borrelia species distinct from previously characterized members of the genus Borrelia. Based on our present study and data from previ ous DNA-DNA hybridizations, a new Borrelia species, Borrelia valaisian a sp. nov., in the B. Burgdorferi complex, is proposed. Strain VS116 i s the type strain of this new species.