Abstract
Purpose: :
To evaluate the effectiveness of photodynamic antimicrobial chemotherapy (PACT) on Staphylococcus aureus (S.aureus).
Methods: :
A derivative of porphyrin (TONS504; Porphyrin Lab, Okayama) with light emitting diode (LED) exposure in response to an LED lighting device (CCS Inc., Kyoto) was applied in vitro onto 107 colony forming units of S.aureus. The LED lighting device, which can supply a single wave length (660 nm) was applied with 10, 20 and 30 J. Various concentrations of TONS504 were applied (0.01 to 10 ug/mL) followed by LED exposure, and then the bacterial suspensions were incubated overnight at 37°C. The growth activity of S. aureus was evaluated by a culture of the bacterial suspensions on standard agar overnight, and then was confirmed by counting the bacterial colony formation at 24 hours after the start of the culture.
Results: :
TONS504-PACT showed a dose-dependent inhibition on S.aureus. The completely inhibitory concentration of TONS504 was 1 ug/mL with 10 J, 0.5 ug/mL with 20 J and 0.5 ug/mL with 30 J of LED exposure. However, TONS 504 showed no inhibition on S. aureus at concentrations ranging between 0.01 to 10 ug/mL without LED exposure.
Conclusions: :
TONS504-PACT was therefore found to have a bactericidal effect in vitro on S.aureus.
Keywords: antibiotics/antifungals/antiparasitics • photodynamic therapy • keratitis