Skin Commensal Malassezia globosa Secreted Protease Attenuates Staphylococcus aureus Biofilm Formation

Skin provides the first defense against pathogenic micro-organisms and is also colonized by a diverse microbiota. Phylogenetic analysis of whole skin microbiome at different skin sites in health and disease has generated important insights on possible microbial involvement in modulating skin health. However, functional roles of the skin microbial community remain unclear. The most common sebaceous skin commensal yeasts are the basidiomycetes, Malassezia. Here, we characterized the dominant secreted Malassezia globosa protease in culture and subsequently named it Malassezia globosa Secreted Aspartyl Protease 1 (MgSAP1). We defined recombinant MgSAP1's substrate cleavage profile using an unbiased, mass-spectrometry-based technique. We show that this enzyme is physiologically relevant as mgsap1 expression was detected on at least one facial skin site of 17 healthy human volunteers. In addition, we demonstrated that this protease rapidly hydrolyzes Staphylococcus aureus protein A, an important S. aureus virulence factor involved in immune evasion and biofilm formation. We further observed that MgSAP1 has anti-biofilm properties against S. aureus. Taken together, our study defines a role for the skin fungus Malassezia in inter-kingdom interactions and suggests that this fungus and the enzymes it produces may be beneficial for skin health.