Dermatophytes are highly infectious fungi that cause superficial
infections in keratinized tissues in humans and animals. This group of fungi is defined by their ability to digest
keratin and encompasses a wide range of species. We investigated a critical adhesion
protein,
subtilisin 3, utilized by Microsporum canis during initial stages of
infection, analyzing its production and expression under varying growth conditions. Additionally, as this
protein must be expressed and produced for dermatophyte
infections to occur, we developed and optimized a diagnostic antibody assay targeting this
protein.
Subtilisin 3 levels were increased in culture when grown in baffled flasks and supplemented with either
l-cysteine or cat hair. As
subtilisin 3 was also produced in cultures not supplemented with
keratin or
cysteine, this study demonstrated that
subtilisin 3 production is not reliant on the presence of
keratin or its derivatives. These findings could help direct future metabolic studies of dermatophytes, particularly during the adherence phase of
infections.