Oral

[O3-E-PM1-04] Bactericidal Effect of 5-Aminolevulinic Acid Mediated Photodynamic Therapy on Fusobacterium nucleatum

〇Chao Wang^1,2, Takayuki Nambu², Hiroki Takigawa², Hugo Maruyama², Chiho Mashimo², Toshinori Okinaga² (1. Dept Bacteriol, Osaka Dent Univ Grad Sch Dent, 2. Dept Bacteriol, Osaka Dent Univ)

Keywords:Fusobacterium nucleatum、5-aminolevulinic acid、Photodynamic therapy

Antimicrobial photodynamic therapy (PDT) is known as a treatment that combines photosensitizing agents with specific wavelengths of light to inactivate microorganisms without creating drug-resistant bacteria. We have previously shown that Fusobacterium nucleatum is specifically disinfected in the oral microbiota when dental plaque samples were irradiated with blue light targeting endogenous porphyrins. F. nucleatum is a Gram-negative anaerobic rod ubiquitous to the oral cavity and has been associated not only with periodontitis but also with colon cancer and systemic diseases. The amount of porphyrin-type photosensitizers in bacterial cells may be increased by adding the metabolic intermediate product 5-aminolevulinic acid phosphate (5-ALA) to the environment. In this study, we examined the bactericidal potential of 5-ALA-mediated PDT (ALA-PDT) against F. nucleatum and its effect on the microbiota. When F. nucleatum was incubated in a culture medium containing 0.5% 5-ALA, blue LED irradiation inactivated more than 95% of F. nucleatum. In addition, when collected plaques were cultured in vitro and treated with ALA-PDT, a highly efficient and specific reduction in the ratio of Fusobacterium spp. was observed. Fluorescence spectral analysis showed that F. nucleatum produced excitable photosensitive substances after the addition of 5-ALA. These results indicate that ALA-PDT may be an effective method for the specific removal of F. nucleatum in plaque.