Comparative study of in vitro methods used to analyse the antifungal activity of propolis against Trichophyton rubrum and Trichophyton mentagrophytes

Abstract

The aim of this study was to evaluate the in vitro activity of propolis against clinical isolates of Trichophyton rubrum and Trichophyton mentagrophytes by following the NCCLS guidelines for testing filamentous fungi, and compare the two methods of evaluating the efficacy of propolis: NCCLS microdilution and agar dilution methods. A broth microdilution method following the recom-mendations established by the National Committee for Clinical Laboratory Standards (NCCLS) and agar dilution method were used to compare the in vitro activity of propolis with that of itraconazole (ITC) against 29 clinical isolates the dermatophytes belonging to two different species of Trichophyton. In terms of MICs (minimal inhibitory concentrations), ITC showed greater activity than propolis. MICs of propolis at which 50% (MIC50) and 90% (MIC90) of the isolates were 0.1 and 0.2 μg ml-1, respectively. Propolis merits further investigations as a potentially useful agent for treatment of dermatophytosis and the broth microdilution and the agar dilution methods were good agreement for propolis against dermatophytes. Moreover, the study suggests the potential value of the broth microdilution as a convenient alternative method for testing the susceptibilities of dermatophytes to propolis.