Comparison of photoinactivation of T. rubrum by new methylene blue (NMB) and indocyanine green (EmunDo (R))

Abstract

Background: Superficial mycotic skin infections which are predominantly caused by Trichophyton rubrum, poorly responsd to conventional therapies. A great amount of attention has focused on finding more effective treatments. The current work is aimed to compare the effectiveness of phoinactivation of Trichophyton rubrum by two relatively new photosensitizers: a phenothiazinium dye(New methylene blue) and Indocyanine green (EmunDo (R)). Materials and methods: A Final inoculum of T. rubrum which corresponded to 10(6) colony forming unit per milliliter (CFU ml(-1)) was prepared. Antimicrobial Photodynamic treatment (aPDT) of T. rubrum was carried out by either EmunDo (R) (1 mg/ml, Infra-red laser (IRL, lambda = 810 nm, Energy Density 55 J/cm(2))) or NMB (10 mu M, Red laser (RL), lambda = 630 nm, Energy Density of 5 J/cm(2)). The suspensions thereafter were subcultured on Sabouraud dextrose agar (SDA) and were counted on due time. based on colony-forming unit per milliliter (CFU/ml). Results: aPDT with either EmunDo (R) (E) or NMB (N) considerably diminished the viability of inoculated T. rubrum with respective reduction of 0.64 log and 0.4 log compared to the control group (P < 0.001). No significant difference was found between two laser only groups (P = 0.79) and two aPDT groups (P = 0.73), however significant reduction of T. rubrum in red laser only group (P = 0.04) and EmunDo (R) only group (P = 0.04) was found as compared to the control group (P < 0.05). Conclusion: The study provides evidence regarding satisfactory photodynamic inactivation of T. rubrum with EmunDo (R) or NMB as photosensitizers. Irradiation by only red laser source was found superior to only infra-red laser source. Dark toxicity of EmunDo (R) was more successful than new methylene blue dye. (C) 2017 Published by Elsevier B.V.