[Ability of lactobacilli in the human microflora to produce lysozyme]

Lysozyme activity of 403 strains of lactobacilli were investigated; of these 26 were from foreign sets and 377 were isolated from the contents of the stomach, feces and vaginal discharge of healthy adults. The species reference of lactobacillae was confirmed by the results of study of their physiologo-biochemical properties with the aid of 45 tests. A method of agar plates was adapted to determination of lysozyme: the autoclaved suspension of Micrococcus lysodeikticus (strain No. 2665) was added to the agar medium MPC-I, and lactobacilli were cultivated for 4 days in the CO2 atmosphere at 37 degrees C. There was revealed the capacity of L. fermenti and L. brevis to produce lysozyme; in L. fermenti the lysozyme activity was much more frequent (p less than 0.001); strains of the rest of the species of lactobacilli differentiated by the Rogosa and Sharpe's classification proved to be lysozyme-negative. It was shown that the lactobacilli of the L. fermenti species, included into the microflora of the intestine and the vagina of healthy adults as a rule possessed lysozyme activity. L. fermenti strain 90T-S4 used in the production of dry lactobacterin also produced lysozyme. All this favours an important role of L. fermenti in the protective function of the microflora.