Mechanism of bactericidal activity of lysolecithin and its biological implication.

Lysolecithin exhibited bactericidal effect on mycobacteria and staphylococci, but not on E. coli. The effect on staphylococci was manifested shortly after exposure, but that on mycobacteria was of the delayed type. The mycobactericidal activity was dependent on the fatty acid moiety of the chemical structure reflecting the cytotoxicity of the free form. The activity on staphylococci was not, however, of such fatty acid dependency and showed the same pattern of molecular species in hemolytic activity. These and other collateral findings suggest that the mycobactericidal effect of lysolecithin is due to the free fatty acids released therefrom by the enzymatic activity of the exposed bacterial cells, but that staphylococci are killed by the detergent effect of the whole lysolecithin molecule.