Identification of carbon dioxide as a dermatophyte inhibitory factor produced by Candida albicans

Abstract

A factor produced by Candida albicans, which inhibits dermatophyte growth and induces arthrospore formation is characterized and identified. Candida dermatophyte inhibitory factor (CDIF) is volatile and fungistatic. Analysis of volatile materials produced by C. albicans was performed by gas chromatography. Only a single volatile substance was detected and was subsequently identified as carbon dioxide. The involvement of carbon dioxide in the inhibition of dermatophytes was demonstrated by: (1) utilization of commercial carbon dioxide to produce dermatophyte inhibition as well as arthrospore formation, and (2) prevention of dermatophyte inhibition by C. albicans through incorporation of soda lime into the incubation atmosphere. The ability of carbon dioxide to inhibit dermatophyte growth was shared with other gases (methane and helium), but arthrospore formation was observed only with carbon dioxide. The possible significance of carbon dioxide's induction of arthrospores, a form occasionally observed in active dermatophyte lesions, is discussed.