The aim of this study was to evaluate in vitro the bactericidal effect of Antimicrobial Photodynamic Therapy - AmPDT using a phenothiazinium compound (toluidine blue O and methylene blue, 12.5 μg/mL) on Staphylococcus aureus (ATCC 23529) irradiated or not with the red laser (λ 660 nm, 12J/cm²). All tests were performed in triplicate and samples distributed into the following groups: Negative control, Laser, Photosensitizer, and AmPDT. Bactericidal effect of the Antimicrobial Photodynamic Therapy was assessed by counting of colony-forming units and analyzed statistically (ANOVA, Tukey test, p<0.05). The results showed, comparing the Laser group with Negative control, a statistically significant increase of counting on the Laser group (p = 0.003). The use of the photosensitizer alone reduced the mean number of CFU (64.8%) and its association with the Laser light resulted in 84.2% of inhibition. The results are indicative that the use of Antimicrobial Photodynamic Therapy presented in vitro bactericidal effect on Staphylococcus aureus.

Date Published: 5 March 2015
PDF: 6 pages
Proc. SPIE 9309, Mechanisms for Low-Light Therapy X, 93090X (5 March 2015); doi: 10.1117/12.2079170

Published in SPIE Proceedings Vol. 9309:
Mechanisms for Low-Light Therapy X
Michael R. Hamblin; James D. Carroll; Praveen Arany, Editor(s)