PURPOSE OF THE STUDY
Phylogenetic typing of F. tularensis subsp. holarctica strains. isolated on the Russian Federation territory in the period from 1966 to 2023.
MATERIALS AND METHODS
The work used the nucleotide sequences of the genomes of 36 strains isolated on the Russian Federation territory. The phylogenetic analysis also included the genomes of 27 strains obtained from the NCBI database. Based on 6626 single nucleotide polymorphisms (SNPs) identified in the F. tularensis genome, a dendrogram of the relationships of the studied strains was constructed.
RESULTS
By analyzing whole-genome sequencing data of F. tularensis subsp. holarctica isolated on the Russian Federation territory from 1966 to 2023, it was shown that erythromycin-sensitive strains isolated in the territories of Altai in 2011 and Khabarovsk Territory in 1975 belong to the main phylogenetic group B.4. Erythromycin-sensitive strains of F. tularensis subsp. holarctica, isolated in the territories of the Rostov region in 1996 and the Khabarovsk Territory in 1966, belong to the main phylogenetic group B.6, subgroup B.7. The studied erythromycin-resistant strains of F. tularensis subsp. holarctica belong to group B.12, subgroups B.26-B.20, B.26-B.23 and B.27. On the territory of the Rostov region, in addition to erythromycin-sensitive ones, there are circulating strains of the tularemia pathogen belonging to the subgroup B.26-B.20, as well as those belonging to the subgroup B.27, which are also common in the territory of the Donetsk People’s Republic. Erythromycin-resistant strains of F. tularensis subsp. holarctica, isolated on the territory of the Khanty-Mansiysk Autonomous Okrug in 2013 and containing different numbers of tandem repeats of the M-3 locus, belong to different lines of the B.26 subgroup. The strains obtained on the territory of Kalmykia in 1987 belong to the subgroup B.26 (B.23).
CONCLUSION
The identity of the F. tularensis subsp. holarctica strains, isolated on the territory of Russia, to three main phylogenetic groups B.4, B.6 and B.12 was determined. The genetic diversity of tularemia causative agent strains is shown, as well as the circulation of several genotypes in one territory for a long time.