In vitro influence of photodynamic antimicrobial chemotherapy onstaphylococcus aureusby using phenothiazines derivatives associated with laser/LED light

Abstract

The aim of this study was to evaluate the effect of photodynamic antimicrobial chemotherapy (PACT) using phenothiazinium dyes - PTZ irradiated with red laser (ʎ660nm) or red-orange LED (ʎ632±2nm) on Staphylococcus aureus in vitro. triplicate tests were performed in 10 groups: control, Laser (L1+P- and L2+P-) bacterial suspensions were irradiated only with laser energy 2.4 and 4.8 J/cm2 respectively, (Led1+P- and Led2+P-) irradiated only with LED energy 2.4 and 4.8 J/cm2 respectively, (L1+P+ and L2+P+) irradiated with laser in the presence of 1μg/ml of photosensitizer, (Led1+P+ and Led2+P+) irradiated with LED in the presence of 1μg/ml of photosensitizer and finally (L-P+) only in the presence of PTZ dye. Bactericidal effect of the PACT was assessed by counting colony-forming units. The results showed no significant difference on regards different energy densities on group PACT for both lights. PACT groups (L2+P+ and Led2+P+) compared to the Control showed significant reduction of CFUs. LED/Laser groups (L2+P- and Led2+P-) compared to control and PTZ groups showed also significant differences as groups LED/Laser (4.8J/cm2) increased the average of CFUs. Although the results of this study have shown a reduction in average number of colonyforming units by the appropriate Laser or LED-dye treatment combination, it this topic requires further investigation.