Genus-level identification of dermatophytes by MALDI-TOF MS after 2days of colony growth.

Abstract

In this study, a two-step workflow for the identification of clinical dermatophytes using MALDI-TOF analysis and commercially available spectral library was developed. The workflow consists of an initial direct deposition of the sample on the MALDI plate and formic acid protein extraction at 2days of growth culture; if dermatophyte identification is not successful, a complete protein extraction using ethanol-formic acid-acetonitrile is subsequently performed. Using this workflow, the correct isolate identifications increase up to 90%; of these, 27% are identified at the genus-level, providing sufficient information to start an antifungal treatment. The method here proposed represents a fast and useful approach to differentiate dermatophytes grown in culture.