In Vitro Antifungal Activity of Green Synthesized Silver Nanoparticles in Comparison to Conventional Antifungal Drugs Against Trichophyton Interdigitale, Trichophyton Rubrum and Epidermophyton Floccosum

Abstract

Background: Dermatophytosis is a globally distributed fungal infection. Treatment failure and relapse is common in this disease. Silver nanoparticles are known for their promising antimicrobial activity. The aim of this study was to determine the antifungal activity of these nanoparticles against common dermatophyte species.

Methods: A set of 30 molecularly identified dermatophytes including Trichophyton interdigitale (n=10), Trichophyton rubrum (n=10), and Epidermophyton floccosum (n=10) were used in this study. Green synthesized silver nanoparticles using chicory (Cichorium intybus) were tested for their antifungal activity in comparison to fluconazole, itraconazole and terbinafine. Interspecies differences in minimum inhibitory concentrations of antifungal drugs and silver nanoparticles were tested using Kruskal-Wallis test in SPSS software version 21.

Results: The highest minimum inhibitory concentrations (MICs) among antifungal drugs were observed for fluconazole [range: 4-64 μg/mL, geometric mean (GM) =17.959 μg/mL], followed by itraconazole (range: 0.008-0.5, GM= 0.066) and terbinafine (range: 0.004-0.25 μg/mL, GM=0.027 μg/mL). Silver nanoparticles showed potent antifungal activity against all dermatophyte isolates with MICs (range: 0.25-32 μg/mL, GM=4.812 μg/mL) higher than those of itraconazole and terbinafine, but lower than fluconazole. MIC values of silver nanoparticles demonstrated significant differences between species (P=0.044), with E. floccosum having the highest MICs (GM=9.849 μg/mL) compared to T. interdigitale (GM=3.732 μg/mL) and T. rubrum (GM=3.031 μg/mL).

Conclusion: Silver nanoparticles demonstrated promising anti-dermatophyte activity against the studied dermatophytes. Due to their wide-spectrum activity against other fungal and bacterial pathogens, they could be a potential choice, at least in the case of cutaneous and superficial infections.

Keywords: Antifungal agents; Epidermophyton; Rubrum; Trichophyton; nanoparticles; tinea.