[Influence of active forms of oxygen on adhesive characteristics and biofilm production by bacteria]

Study of influence of low concentrations of active forms of oxygen on the ability of bacteria to form biofilms and their adhesive characteristics.

Modification of the studied properties of bacteria was performed by treatment of the bacteria with hydrogen peroxide or hydroxyl radicals at concentrations of 0.5 mM that causes death of 5 - 7% of cells and non-lethal - 0.05 and 0.005 mM. Adhesive characteristics of Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Klebsiella pneumoniae bacteria were determined by using human erythrocytes. The degree of biofilm formation in plates modified by collagen from human fibroblasts was determined by the amount of bound crystal violet.

A significant decrease (7 - 17%) of the adhesion of E. coli, S. aureus, K. pneumoniae to erythrocytes under the influence of hydrogen peroxide and hydroxyl radicals at the concentrations of 0.5 and 0.05 mM when compared with the control was detected. 11 - 40% stimulation of E. coli, S. aureus, K. pneumoniae biofilm formation by active forms of oxygen in all the used concentrations with simultaneous insignificant biomass growth increase was noted. Active forms of oxygen did not influence significantly the studied properties of B. subtilis.

Active oxygen forms have regulatory influence on the character of interaction of bacteria with surfaces colonized by them, that determines structural-functional state of microbial biocenoses.