New Genetic Markers for Molecular Typing of Bacillus anthracis Strains

Abstract

Objective: Identification of new markers for the molecular typing of Bacillus anthracis. Materials and methods. The genomes of 16 B. anthracis strains from the collection of the Stavropol Research Anti-Plague Institute, 11 B. anthracis strains and 5 strains of Bacillus cereus from GenBank were investigated. The methods of in vitro and in silico analysis of canonical and whole-genome single nucleotide polymorphisms (SNP), genome regions with variable number of tandem repeats (VNTR) were used for the analysis. Results and discussion. It has been established that there are deletions and (or) SNPs in some of B. anthracis strains of the main genetic lineage B, within the homologous genes of the tri-cistronic operon gerH, which encodes spore germination proteins. gerA genes contain the Bams34 VNTR locus, the sizes of genes in different strains vary due to the different number of tandem repeats and the presence of indels, which suggests the variability of GerA spore germination proteins. In the area of reverse primer annealing, some of them have several SNPs or deletions, which makes impossible PCR amplification of the Bams34 locus. Previously not described VNTR locus, SNPs and indels in sequences of plasmids pXO1 and pXO2, as well as SNP in chromosomal gene of glycerol-3-phosphate transporter were identified. Two pairs of PCR primers for the variable regions of the plasmids were designed. VNTR-locus, SNP and indels in sequences of plasmids pXO1 and pXO2 are suitable genetic markers for the differentiation of typical virulent diplasmid strains belonging to the main genetic lineages of B. anthracis A, B and C. The allele T of SNP within chromosomal glpT gene is specific for one of two strains isolated during the outbreak of anthrax and distinguishes it from all other strains of B. anthracis.

Keywords

• bacillus anthracis
• molecular typing
• snp
• vntr
• indels
• main genetic lineages