A Two-Way Road: Antagonistic Interaction Between Dual-Species Biofilms Formed by and .

Dermatomycoses include superficial fungal infections of the skin and its appendages. , , and are some of the most prevalent species that cause dermatomycoses. Several studies show a variable predominance of spp. in relation to dermatophytes, especially in onychomycosis and the possibility of isolating both from the same site. The ability of dermatophytes to form biofilms recently been explored and there is currently no evidence on the involvement of these filamentous fungi in multi-species biofilms. Thus, this study aims to investigate the probable dual-species interaction between and and and biofilms, considering variable formation conditions, as well as the susceptibility of these dual-species biofilms against terbinafine and efinaconazole. Three conditions of formation of dual-species biofilms were tested: (a) the suspensions of and or placed together; (b) suspensions of and added the pre-adhesion of biofilms; (c) after the maturation of sessile cells. In the first and second conditions, the quantification of metabolic activities, biomass, and polysaccharide materials of mixed biofilms tended to resemble monospecies biofilms. In the third condition, the profiles were modified after the addition of , suggesting that biofilms served as substrate for the development of biofilms. Scanning electron microscopy showed predominance, however, numerous blastoconidia were noted, most evident in the conditions under which was added after the pre-adhesion and maturation of biofilms. Despite the predominance of , the presence of appears to inhibit filamentation and development, confirming an antagonistic interaction. Fungal burden assays performed when the biofilms were formed together confirmed predominance, as well as susceptibility to antifungals. Further studies will be needed to identify the components of the and biofilm supernatants responsible for inhibiting dermatophyte growth and filamentation.