In vitro activity of Citrus bergamia (bergamot) oil against clinical isolates of dermatophytes

Abstract

Recently, bergamot oil was shown to be a potent antifungal agent in vitro against clinically important Candida species. In this study, the activities of bergamot natural essence and its furocoumarin-free and distilled extracts on dermatophytes such as Trichophyton, Microsporum and Epidermophyton species were investigated. In vitro susceptibility testing assays on 92 clinical isolates of dermatophytes (Trichophyton mentagrophytes n = 20, Trichophyton rubrum n = 18, Trichophyton interdigitale n = 15, Trichophyton tonsurans n = 2, Microsporum canis n = 24, Microsporum gypseum n = 1 and Epidermophyton floccosum n = 12) were performed using the CLSI M38-A broth microdilution method, except for employing an inoculum of 1-3 x 10(3) cfu/mL. MICs were determined at a visual endpoint reading of 80% inhibition compared with the growth control. MICs (v/v) of all fungi ranged from 0.156% to 2.5% for the natural essence, from 0.02% to 2.5% for the distilled extract, and from 0.08% to 1.25% for the furocoumarin-free extract. The three isolates of T. tonsurans and M. gypseum exhibited the highest MIC values. Data from this study indicate that bergamot oil is active in vitro against several common species of dermatophytes, suggesting its potential use for topical treatment of dermatophytoses.