[Effect of metabolites of H2O2-producing lactobacilli on functional activity of lysozyme].

Aim: Study the effect of metabolites of H2O2-producing lactobacilli on enzymatic and bactericidal activity of lysozyme.

Materials And Methods: 9 H2O2-producing vaginal lactobacilli, Micrococcus luteus NCTC 2665, Escherichia coli State Institute of Standardization and Control No 240367, Lactobacillus acidophilus Institute of Cellular and Intracellular Symbiosis No 37 were used. Ability of lactobacilli to produce H2O2 was evaluated by oxidation of tetramethylbenzidine by peroxidase. Lysozyme was modified by mixing with equal volumes of lactobacilli metabolites, metabolites of H2O2-producing vaginal lactobacilli previously treated with catalase were used in control. Lysozyme enzymatic activity was determined by speed of M. luteus lysis, bactericidal--by survivability of E. coli in Endo medium and L. acidophilus--in MRS medium.

Results: Decrease of enzymatic activity of lysozyme due to its contact with H2O2-producing lactobacilli metabolites was detected. This effect is accompanied by growth of bactericidal activity of lysozyme against E. coli and decrease against L. acidophilus. The degree of changes of enzymatic and bactericidal activity of lysozyme by lactobacilli metabolites depended on concentration of hydrogen peroxide in them.

Conclusion: Modification of lysozyme by H2O2-producing lactobacilli metabolites resulting in opposite changes of its activity against autochthonous and allchthonous bacteria is one of the mechanisms of formation of stable microbial biocenosis in human organism.