Antimicrobial Photodynamic Therapy Mediated by Fotenticine and Methylene Blue on Planktonic Growth, Biofilms, and Burn Infections of .

Antimicrobial photodynamic therapy (aPDT) is considered a promising alternative strategy to control infections. In this study, we evaluated the action of aPDT mediated by a new photosensitizer derivative from chlorin e-6 (Fotoenticine-FTC) on comparing its effects with methylene blue (MB). For this, aPDT was applied on in planktonic growth, biofilms, and burn infections in . The absorption of FTC and MB by bacterial cells was also evaluated using microscopic and spectrophotometric analysis. The results of planktonic cultures showed that aPDT reduced the number of viable cells compared to the non-treated group for the reference and multidrug-resistant strains. These reductions varied from 1.4 to 2 log CFU for FTC and from 2 log CFU to total inhibition for MB. In biofilms, aPDT with MB reduced 3.9 log CFU of , whereas FTC had no effect on the cell counts. In , only MB-mediated aPDT had antimicrobial activity on burn injuries, increasing the larvae survival by 35%. Both photosensitizers were internalized by bacterial cells, but MB showed a higher absorption compared to FTC. In conclusion, MB had greater efficacy than FTC as a photosensitizer in aPDT against .