Cell-surface hydrophobicity and lipolysis as essential factors in human tinea nigra.

Hydrophobic adhesion of cells of the black yeast Hortaea werneckii (Horta) Nishimura & Miyaji, causative agent of human tinea nigra, was established by microbial adhesion to hexadecane (MATH) and adhesion to polystyrene, and compared with adhesion of other species of black yeasts. Additional ecophysiological tests were performed. Hortaea werneckii cells proved to have a high degree of hydrophobicity (98.5% MATH). The species is unable to degrade keratin, but shows significant lipolytic activity. It is concluded that H. werneckii is a commensal, that shows lipophilic adhesion to human skin and survives by the assimilation of excretion products.