PROTECTIVE PROPERTIES OF THE VACCINE STRAIN 55-VNIIVVIM AND ACAPSULAR STRAIN BACILLUS ANTHRACIS 363/11

Objective of the work was to determine protective potential and safety for animals of the naturally attenuated B. anthracis 363/11 monoplazmid non-capsular strain to be used as a new candidate vaccine strain for the development and enhancement of specific prophylaxis of anthrax. Materials and methods. Vaccine strain 55-VNIIVViM that is used for welfare provision as regards anthrax in animals in the territory of Russia was employed for the comparison of protective properties. Identification of LD50, ImD50 and protective efficacy was carried out using standard protocols for modeling the infection on laboratory (white mice, guinea pigs) and targeted (sheep) animals. Results and conclusions. It is established that avirulent for white mice B. anthracis 363/11 strain demonstrates higher protective and immunogenic activity than 55-VNIIVViM strain. It does not reverse to the virulent variant after passaging on the nutrient media and in the organism of susceptible animals. Thus it allows for considering B. anthracis 363/11 strain as a promising candidate vaccine strain, the utilization of which will improve epizootic situation on anthrax in the Russian Federation

BIOLOGICAL PROPERTIES AND MOLECULAR-GENETIC CHARACTERISTICS OF BACILLUS ANTHRACIS STRAINS, ISOLATED DURING THE OUTBREAK OF ANTHRAX IN THE YAMALO-NENETS AUTONOMOUS DISTRICT IN 2016

Objective of the study was to identify phenotypic properties and genetic peculiarities of Bacillus anthracis strains, isolated during the outbreak of anthrax in the territory of Yamal in 2016. Materials and methods. Investigated were the strains of anthrax agent, applying basic and subsequent identification tests and canSNP-, MLVA-genotyping methods and whole genome sequencing. Results and conclusions. The results showed the identity of the phenotypic properties, canSNPand MLVA25-genotypes, and profiles of whole genome-sequencing, regardless of the source of the strains isolation. Confirmed was a common source of human infection. Defined were phylogenetic interrelations of the tested strains and their position in global B. anthracis population. For the first time ever explored was variability of the gene pattern, associated with pathogenicity, and demonstrated – the efficiency of the proposed algorithm for genetic typing