In vitro Testing of Trichophyton indotineae Susceptibility to Essential Oil Components Citral and Thymol

Tinea corporis caused by Trichophyton indotineae infection is a worldwide epidemic and represents a growing challenge, given that many strains of this dermatophyte are resistant to the antifungal drugs (allylamine and azoles) typically used to treat dermatophytosis. Phytochemicals isolated from essential oils are effective alternatives for inhibiting microbial pathogens. In the present study, we performed in vitro susceptibility testing of the phytochemicals citral and thymol against T. indotineae strains, including a multi-drug-resistant isolate. The susceptibility of T. indotineae to citral, and thymol was assessed using the modified CLSI M38-A2 guideline broth microdilution method. The ranges of the minimum inhibitory concentration (MIC, expressed as a percentage) of the phytochemicals in all isolates were 0.0015 to 0.006% for citral and thymol. Citral and thymol appear effective against T. indotineae at the tested concentrations, and therefore may be of use in skin care items intended to protect from this infection.