Molecular genotyping of 15 B. anthracis strains isolated in Eastern Siberia and Far East.

Bacillus anthracis is a pathogenic bacterium, which causes anthrax disease. The ability of this bacterium to form spores, which can be preserved in soil for decades and cause outbreaks later on, makes this pathogen a serious problem for veterinary and health services of many countries. Siberia is one of the most anthrax-influenced regions of Russia. In this research we report on the results of genotyping based on whole genome SNP analysis of 15 strains, isolated on the territory of Eastern Siberia and the Far East in 1956-2018. In this research, we sequenced 15 genomes of B. anthracis strains isolated from infected humans and animals, and from soil samples from the territory of Eastern Siberia and the Far East in the period from 1956 to 2018. We used genomic sequences obtained in this study and 219 B. anthracis genomes available in the international GenBank database to perform a comparative analysis. As a result we detected 6400 chromosomal SNPs which allowed to differentiate the studied strains. We built phylogenetic reconstruction of the global B. anthracis population based on the detected SNPs using the Maximum Likelihood Method and described genetic diversity of the strains isolated on the territory of Eastern Siberia and the Far East. Strains, isolated on this territory from 1956 to 2018 belong to 5 different genetic groups: "Ames", "STI", "Tsiankovskii", "Siberia" and "Asia". The greatest diversity of the strains is registered for two regions of the southern part of Eastern Siberia - Tyva and Buryatia. This research expands current understanding of genetic diversity of B. anthracis strains circulating on the territory of Russia.

Phylogenetic analysis of Bacillus anthracis strains from Western Siberia reveals a new genetic cluster in the global population of the species.

BACKGROUND: Anthrax is a zoonotic disease caused by the gram-positive bacterium Bacillus anthracis. The most anthrax-endemic regions of Russia are Siberia and North Caucasus. Previously, genotyping of Russian B.anthracis isolates was carried out using canSNP and MLVA data; these methods yield lower resolution results compared to whole genome SNP analysis (wgSNP). In this research, we have used wgSNP method for genotyping of 10 B.anthracis isolates, obtained during 1961-2016 in Russia on territory of Western Siberia. RESULTS: We have analyzed 185 B.anthracis genomes available in GenBank database and genomes of 10 isolates obtained in this study to determine the place of Russian isolates in the global phylogeny of B.anthracis. For the studied genomes we have detected 7203 SNPs, which were used for building a phylogenetic reconstruction with Maximum Likelihood Method. Results of the phylogenetic analysis indicate that Russian strains belong to three different genetic groups. Three strains belong to genetic group "Ames", two strains - to "STI" group. Five strains belong to the main genetic line B, and four of them form a subcluster, described for the first time, which we have named "Siberia". CONCLUSIONS: In this study, the data on genetic diversity of B.anthracis strains on the territory of Western Siberia is presented for the first time. As a result of complex phylogenetic analysis, the place of these isolates was determined in the global phylogenetic structure of the B.anthracis population. We describe a new cluster in the main genetic line B for the first time.

Genotyping and phylogenetic location of one clinical isolate of Bacillus anthracis isolated from a human in Russia.

BACKGROUND: Anthrax is a zoonotic disease caused by the Gram-positive bacterium Bacillus anthracis. In Russia, there are more than 35 thousand anthrax stationary unfavourable sites. At the same time, there is very little published information about the isolates of B. anthracis from the territory of Russia. In this study, we report the use of whole genome sequencing (WGS) and bioinformatics analysis to characterize B. anthracis 81/1 strain isolated in Russia in 1969 from a person during an outbreak of the disease in the Stavropol region. RESULTS: We used 232 B. anthracis genomes, which are currently available in the GenBank database, to determine the place of the Russian isolate in the global phylogeny of B. anthracis. The studied strain was characterized by PCR-based genetic methods, such as Multiple-Locus Variable-Number Tandem Repeat Analysis (MLVA), canonical single nucleotide polymorphisms (canSNP), as well as the method of full-genomic analysis of nucleotide polymorphisms (wgSNP). The results indicate that the Russian B. anthracis 81/1 strain belongs to Trans-Eurasion (TEA) group, the most representative in the world. CONCLUSIONS: In this study, the full genomic sequence of virulent B. anthracis strain from Russia was characterized for the first time. As a result of complex phylogenetic analysis, the place of this isolate was determined in the global phylogenetic structure of the B. anthracis population, expanding our knowledge of anthrax phylogeography in Russia.