DESCRIPTIONS OF MEDICAL FUNGI

Descriptions of Medical Fungi 27
Aureobasidium pullulans has a worldwide distribution and is usually isolated as
a saprophyte, occasionally from skin and nails. It has also been reported as a rare
causative agent of phaeohyphomycosis, mycotic keratitis and peritonitis in patients on
continuous ambulatory peritoneal dialysis (CAPD).
RG-1 organism.
Aureobasidium pullulans (de Bary) Arnaud
Morphological Description: Colonies are fast growing, smooth, soon covered with
slimy masses of conidia, cream or pink, later becoming brown or black. Hyphae are
hyaline and septate, frequently becoming dark-brown with age and forming chains of
one to two-celled, thick-walled, darkly pigmented arthroconidia. These arthroconidia
actually represent the Scytalidium anamorph of Aureobasidium and are only of
secondary importance in recognising members of this genus. Conidia are produced
synchronously in dense groups from indistinct scars or from short denticles on
undifferentiated, hyaline to subhyaline hyphae. Conidia are hyaline, smooth-walled,
single-celled, ellipsoidal but of variable shape and size (8-12 x 4-6 µm), often with an
indistinct hilum (i.e. a mark or scar at the point of attachment). Temperature: optimum
25 O C; maximum 35-37 O C.
Molecular Identification: Recommended barcoding genes are ITS, EF-1α and D1/D2
(de Hoog et al. 2015).
Key Features: Hyphomycete (so-called black yeast) producing hyaline blastoconidia
simultaneously from the vegetative hyphae, which may also form chains of darkly
pigmented, thick-walled arthroconidia.
References: Hermanides-Nijhof (1977), Domsch et al. (2007), McGinnis (1980), de
Hoog et al. (2000, 2015), Najafzadeh et al. (2014).
20 μm
Aureobasidium pullulans showing one to two-celled, darkly pigmented arthroconidia
and hyaline, single-celled, ovoid-shaped conidia which are produced on short denticles.
Antifungal Susceptibility: A. pullulans data from 108 isolates (Najafzadeh et al.
2014 and Australian National data); MIC µg/mL.
Antifungal Range MIC 90
Antifungal Range MIC 90
AmB 0.008-16 1 VORI 0.008-16 2
ITRA 0.008-16 0.5 POSA 0.008-4 0.5