<i>In vitro</i> study of the effect of <i>Bifidobacterium bifidum </i> probiotic strain DNA on the cell concentration and colonization properties of intestinal microsymbionts

Aim. To estimate in vitro the effect of DNA isolated from the probiotic strain Bifidobacterium bifidum 791 on the cell concentration and adhesive properties of fecal isolates of bifidobacteria and opportunistic microorganisms of different species.Materials and methods. DNA was isolated from the probiotic strain Bifidobacterium bifidum 791. Biomass containing bifidobacteria was washed from the nutrient medium. The suspension of bacteria in the buffer solution was subjected to ultrasonic disintegration with a frequency of 40 kHz three times for 30 minutes, followed by centrifugation. The supernatants were combined and purified chromatographically on CL-4B Sepharose. B. breve, B. bifidum, B. infantis, Staphylococcus aureus, Escherichia coli lac-, Enterococcus faecalis, and Candida albicans were used as test cultures, isolated from the intestines of conditionally healthy adults. Results. The nucleic acid solution with a concentration of 3.54 |jg/ml did not affect the cell number of bifidobacteria (p = 0.61). The DNA content in the solution of 14.15-21.23 jg/ml increased the titers of B. bifidum and B. breve by 2 lg CFU/ml compared to the control (p = 0.01), but did not affect the titers of S. aureus, E. coli lac-, E. faecalis, C. albicans (p = 0.73). The DNA solution stimulated the self-aggregation of bifidobacteria in 1.5-2.0 times. The ability to autoaggregate under the influence of bifidobacterial DNA in S. aureus, E. faecalis, C. albicans did not change, in E. coli lacincreased 2.3 times (p = 0.05).Conclusion. A DNA solution of the probiotic strain B. bifidum 791 with a content 14.15-21.23 jg/ml stimulates the reproduction and autoaggregation of fecal B. breve, B. bifidum