Assessment of the subtilisin genes in Trichophyton rubrum and Microsporum canis from dermatophytosis

The presence of subtilisin genes (SUBs) coding for serine proteases with activities keratinolytic on dermatophyte species gives them the ability to adhere and degrade keratin during infection process. The aim of this study was to determine the presence of SUBs in Trichophyton rubrum and Microsporum canis from dermatophyte infections. In the current study, dermatophytes were isolated from human and animal with dermatophytosis. Isolates were identified by direct microscopic and laboratory examination; then, the isolates were examined for the presence of the SUB gene family by PCR with specific primers. This study showed the most frequency of SUB gene families (11/17). At least one virulence gene was observed for 94% (16/17) of the isolates. Statistical analysis revealed significant associations between SUB presence and isolates, origin of isolates (animal or human infection) and infection type (skin, hair, and nail) (P < 0.05). This is the first report on the presence/absence of SUB genes in isolates that were obtained from human and animal infection in Iran, which seems to raise the risk to be pathogenic.