Mitosporic fungus. Hyphomycetes.
Approx. 15 species.
Soil, forest soils, fresh water, aerial portion of plants, fruit, marine estuary sediments, wood.
Wind (when dried out), water droplet.
Widespread, where moisture accumulates, especially bathrooms and kitchens, on shower curtains, tile grout, window sills, textiles, liquid waste materials.
Used in the removal of unwanted components of raw textile materials. Aureobasidium pullulans produces pullulan (a biodegradable polysaccharide) used for packaging of food and drugs. It is processed into fibers which have a shiny gloss like rayon and have the strength of nylon.
Aureobasidium pullulans represents a morphologically heterogenous group of taxonomically related fungi. Very closely related to Hormonema. Older medical texts refer to this fungus by its former name Pullularia pullulans.
Type I allergies (hay fever, asthma).
Type III hypersensitivity pneumonitis: Humidifier fever, Sauna taker's lung.
Rare reports of isolates from skin lesions, keratitis, spleen abscess in a lymphoma patient, blood isolate from a leukemic patient.
Grows well on general fungal media. Yeast-like, beginning cream to pink, becoming dark brown with age.
The identification of A. pullulans without culture is difficult because of the variety of morphologic forms it takes. Generally, we report irregular clumps of dark brown mycelia dividing in more than one plane as Aureobasidium pullulans. Vegetative hyphae from other unrelated dematiaceous fungi, especially those which form chlamydospore-like structures may be indistinguishable from Aureobasidium.
The morphology of Aureobasidium is distinctive (in a broad sense) and is identifiable if enough structures have been lifted by tape. (A. pullulans is a yeast-like organism which, when it is moist, may not lift well on tape.)