The Aureobasidium genus comprises over 15 species, of which A. pullulans is the most widely known. With a worldwide distribution, it is very common in moist environments and usually grows on plants, soil, fruit, wood, sidings and in fresh water and forests.
Aureobasidium is also very common indoors, especially in highly moist, damp, and humid areas like bathrooms, kitchens, tile grout, window frames, caulking and textiles.
Aureobasidium colonies may be pink or black in colour. A. pullulans, in particular, is initially cream to pink in colour with a flat, smooth, and moist texture. Over time, it gets darker and becomes velvety. The wet spores can get distributed by wind upon drying. It grows in cooler climates and may appear alongside Cladosporium.
Aureobasidium and your health
Aureobasidium pullulans is a common allergen, causing allergic reactions such as asthma, hay fever, hypersensitivity pneumonitis and humidifier fever. However, this mold is not a primary human pathogen and it has not been known to produce significant mycotoxins.
A. pullulans can also cause phaehyphomycosis. It has also been reported as a cause of keratomycosis, pulmonary mycosis with sepsis and cutaneous mycoses such as dermatitis. It may also colonize hair, skin and nails in humans.