Background and study aim: Fungal infections affecting the epidermis, hair, and nails are mostly caused by dermatophytes. ‎They can infect immunocompromised and immune-competent patients as well. The study aims to ‎evaluate the use of Resazurin in anti-dermatophytes susceptibility testing‎‎‎‎‎.‎
Patients and Methods: ‎‎‎ Patients with dermatophytic infection, attending dermatology outpatient clinic in Ain Shams ‎University Hospital were examined and 50 clinical specimens were collected. All clinical ‎specimens were cultured on Sabarouds dextrose agar (SDA). To improve sporulation, isolates from ‎SDA were subcultured on Potato Dextrose Agar (PDA) and incubated at 28°C for 7 days. The ‎colonies were collected in sterile saline, to adjust fungal suspension to 0.5 McFarland. The ‎antifungal susceptibility was made using two methods: disc diffusion (DD) and broth microdilution ‎‎(BMD) with and without Resazurin‎‎‎.‎
Results: Antifungal susceptibility results were available after 24 hours by broth microdilution with bioactive ‎dye (Resazurin). While antifungal susceptibility by broth microdilution method without bioactive ‎dye results was available after 48-72 hours and disc diffusion results were available after an ‎incubation period of 7 to 15 days. In addition, using bioactive dye (Resazurin) method was easier ‎in visual interpretation. There were a perfect agreements between the antifungal susceptibility ‎testing of Itraconazole (kappa 1.00), Terbinafine (kappa 0.947) and Fluconazole (kappa 0.878) by ‎disk diffusion method and Broth micro-dilution method without and with bioactive dye ‎‎(Resazurin)‎‎‎‎‎.
Conclusion: Usage of bioactive dyes such as Resazurin can help in providing rapid and accurate antifungal ‎susceptibility results for better patient care‎.  ‎