Sizentsov A.N., Galaktionova L.V.

The influence of iron salts on the growth characteristics and antagonistic activity of soil isolates of Bacillus cereus

The research is devoted to study of the effect of iron salts on the growth characteristics and antagonistic activity against Escherichia coli, Pseudomonas aeruginosa and Salmonella typhimurium bacteria Bacillus cereus. 9 strains of B. cereus bacteria, previously isolated from soils, were used as objects of research, which showed different resistance to solutions of iron salts in the concentration range from 1 M/l to 0.031 M/l. In the course of the work, the following methods were used: serial breeding, seeding and cultivation of bacteria on nutrient media, MALDI ToF MS, agar wells and nephelometric. The maximum values of tolerance and growth were recorded in the B. cereus strain OCT2022.6, which was slightly inferior to OCT2022.2 and OCT2022.9, showing relative resistance to both nitrate and iron sulfate. The pronounced antagonistic properties of the strains were manifested against the background of pre-incubation with iron nitrate in relation to E. coli and P. aeruginosa, and in the sulfate variant, suppression was noted only for 3 strains against P. aeruginosa. Iron sulfate has a more pronounced toxic effect on the growth of the tested B. cereus isolates. The OCT2022.6 strain had the highest resistance to iron nitrate and the ability to suppress opportunistic microorganisms.

Keywords: BACILLUS CEREUS, IRON, TOLERANCE, ANTAGONISTIC ACTIVITY, SUPPRESSIVENESS