Aureobasidium pullulans hyphae and spores, SEM

Coloured scanning electron micrograph (SEM) of the common indoor allergenic mould Aureobasidium pullulans; fungal hyphae producing spores (often growing yeast-like). Synonym - Pullularia. Aureobasidium is a common indoor mould that grows in damp places. It occurs indoors in very damp areas and in free standing water, such as condensate pans, or following a flood. Spores only become airborne through mechanical disruption of contaminated materials or aspiration of contaminated water. It is not a primary human pathogen nor is it recognized as a producer of significant mycotoxins. High airborne levels of this fungus have been associated with allergic complaints probably due to respiratory irritation mediated by cell-wall components (e.g. beta glucans, glycoproteins), it has also been known as an irritant, and to cause pulmonary problems. Magnification: x260 when shortest axis printed at 25 millimetres.