Multilocus sequence analysis of Borrelia burgdorferi s.l. in Russia

Borrelia burgdorferi sensu lato is a species complex that includes the causative agents of Lyme borreliosis (LB). Classification of the complex was greatly influenced by the method of multilocus sequence typing (MLST), proposed in 2008 and analyzing the spatial distribution of sequence types (STs). Despite the fact that Russia is the largest natural focus of LB to date, it is represented by only 3 strains of the 1323 strains deposited in the MLST database. In this paper, we identified STs for 24 B. burgdorferi s.l. strains isolated from ticks from almost all regions of Russia, 16 of which have not been described so far. It has been shown that the Russian isolates of B. afzelii are of Asian origin and are characterized by a lack of territorial mixing of STs. In contrast, B. garinii and B. bavariensis showed ST mixing between different localities. Comparison of MLST data with the results of sequence analysis of rrf–rrl intergenic spacer led to the conclusion that the previously described genomic groups of B. garinii correspond to the genospecies according to the new classification: 20047 corresponds to B. garinii, and NT29 corresponds to B. bavariensis. The genomic group, ChY13p, characterized by an unusual PCR-RFLP profile, belongs to the species B. garinii (prototype strain 20047). Thus, the use of a reliable method to study the phylogeny and evolution of Borrelia based on MLST, helps to clarify the existing classification. The standardized research procedure and database created could become the basis for a global scientific cooperation in LB research.