Safety assessment of Bacillus subtilis strains isolated from the natural environment of Yakutia

The development and further use of bacterial-based preparations requires thorough safety studies of the active ingredient and their components. The article presents the results of the study of toxigenicity and virulence of 17 strains of B. subtilis isolated from the microbiota of wild ungulates by the Republic of Sakha (Yakutia). Toxigenicity was checked by subcutaneous introduction of 0.5 ml of supernatants, virulence by intraperitoneal introduction of 0.5 ml of suspension containing 5x109 CFU/ml of the studied B. subtilis strains to laboratory animals. To ensure the objectivity of the experiments, the suspension and supernatant of one strain were injected into three white laboratory mice. The experimental animals were observed for 10 days, during which their general physiological condition, food intake, increase in live weight, and hair condition were evaluated. During the experiments, the condition of the experimental mice remained satisfactory. Thus, 17 strains of Bacillus subtilis isolated from the intestinal microbiota of wild ungulates do not possess toxigenic and virulent properties in relation to laboratory animals and can be promising for the development of biological preparations.