In Russia effective measures to prevent an introduction and transmission of Anthrax are developed and widely implemented. Despite this, from 2014 to 2016, seven outbreaks of Anthrax occurred in Volgograd, Rostov, Belgorod, Saratov regions, the Republic of Tatarstan, and also six outbreaks in reindeer population in two districts of Yamal. In this article we describe biological and molecular-genetic characteristics of Bacillus anthracis strains isolated during the outbreaks in Volgograd region, Yamal and from the soils of burial in the Chuvash Republic for the past 3 years.
We used a complex of general microbiological methods and author methodologies for studying such biological characteristics as growth morphology in bacteriological culture media, capsule in vivo and in vitro formation, sporulation, biochemical activity, phage sensitivity, toxicity in vitro, plasmid profile, sensitivity to antibiotics, virulence for laboratory animals. MLVA-typing of the anthrax strains was performed for 20 VNTR loci.
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We showed that the main biological characteristics of anthrax strains differed insignificantly. All the strains produced capsule and toxin, produced hemolytic and proteolytic activity, protocatechuic acid, and had a high virulence for laboratory mice in doses with 6-1000 spores. Nine from eleven studied strains had a natural resistance to Polymyxyn B, were sensitive to Levomycetin, Kanamycinum, Penicillin, Tylosin, Streptomycin, Neomycinum, Tetracyclinum, Ampicillinum, and Enrofloksin. Strain of Bacillus anthracis had a resistance to Kanamycinum, and Streptomycin. |
The most significant phenotypic and molecular-genetic differences were found in asporogenous and avirulent strain B. anthracis isolated from a Lappish reindeer dog in Yamal. Strains isolated during one outbreak were grouped into separate clusters, and within the cluster some strains had insignificant differences in 1-2 loci.
The results show that the morbidity of the disease depends on the geographic location of Anthrax in the territory of Russian Federation and that most of the isolated strains have typical characteristics of Bacillus anthracis.