Chlorine e6 유도 광역학 살균효과

Abstract

Recently, new antibacterial strategy has been demanded because of the increased occurrence of drug-resistant bacteria. Accordingly, photodynamic therapy has been attempted for clinical application against drug-resistant bacteria. Antimicrobial photodynamic therapy combines a nontoxic photosensitizer with harmless visible light to generate singlet oxygen and free radicals that kill microorganism. In this study, the author investigated bactericidal effect of photodynamic therapy by using photosensitizer chlorin e6 to pathogenic bacteria including a gram-positive Staphylococuus aureus and gram-negative strains including Pseudomonas aeruginosa, Escherichia coli, and Salmonella enterica serovar Typhimurium. To examine antimicrobial effect of photodynamic therapy, we measured inhibition zone, colony forming units(CFU), and in situ viability of bacterial cells after illumination with an energy density (Diode pumped laser driver LD2030) of 20J/cm2 in the presence of 10?M chlorin e6. We found the increase of inhibition zone on agar plates, the reduction of CFU, and the rapid decrease of viable cell number of all bacterial species examined while those of control bacteria treated solely with either light or photosensitizer were unchanged. The most sensitive bacteria examined was S. aureus, and the E. coli showed the smallest growth inhibition. These findings suggest that this system can be clinically applicable as an alternative antibacterial strategy to treat multiple drug-resistant bacteria. It is further necessary to devise suitable strategies which enhance the permeability of the outer wall in order to make gram-negative bacteria sensitive to the action of photodynamic processes. It should be additional in vivo experiment to see possibility of clinical treatment.