Mycobial community assemblages in sink drains across a university campus

Multiple fungal species, including potential opportunistic pathogens have been previously identified in water systems. Here, we investigated over 250 restroom sink fungal communities across a university campus and evaluated their diversity and core taxa present. Remarkable similarity in mycobial community composition was observed across buildings with Ascomycota consistently dominating. We found a core mycobiome independent of the building sampled, that included Exophiala species, potential opportunistic pathogenic black yeasts. Other prevalent and dominant taxa included Saccharomyces and Fusarium, common built environment fungi. The frequent presence of Malassezia, a common skin commensal, showed the external influence of human activities as a source of fungi to sinks. The study represents a novel exploration of sink P-traps mycobial communities from a public area and highlights their importance as reservoirs of possible pathogenic fungi, as well as emphasizing the relevance of further research in this understudied ecosystem within the built environment.