Genotyping Borrelia burgdorferi sensu lato isolates from Ixodes ricinus ticks in Russia and Ukraine

The four Borrelia burgdorferi sensu lato isolates obtained from I. ricinus ticks collected from the natural loci in Russia and Ukraine that had an unusual RFLP MseI pattern were studied using the sequencing of the rrfA-rrlB spacer and the rrs gene. Isolate Ir-5215 from a tick collected in southern Ukraine represented the recently described genospecies B. spielmanii, which is pathogenic for humans. The three atypical isolates Ir-3519, Ir-4721, and Ir-4812 had 100% identity with the sequence of atypical European B. burgdorferi sensu stricto strains; they constituted a subgroup of B. burgdorferi sensu stricto based on multilocus sequence analysis (MLSA). These data are indicative of the genetic heterogeneity of the current group B. burgdorferi sensu stricto.