The action of photosensitizers and serum in a bactericidal process. II. The effects of dyes: hypericin, eosin Y and saphranine O.

The aim of the present work was to recognize the reasons for differences in the photodynamic action of dyes against various bacterial strains. It is expected that a better understanding of this problem may help in design of new photosensitizers. The sensitivity of 6 various bacterial strains to the photodynamic action of 5 photosensitizers was determined. The hydrophobicity of cell surface and susceptibility of bacteria to the natural defense mechanism of human serum, were estimated. The differences in the photodynamic efficiency of dyes could be contributed to various affinities of cell membrane to dyes, to known details of membrane architecture as well as to different mechanisms of photosensitization.