DESCRIPTIONS OF MEDICAL FUNGI

Descriptions of Medical Fungi 87
RG-2 organism.
Exophiala jeanselmei complex
Exophiala jeanselmei McGinnis & Padhye
Morphological Description: Colonies are initially smooth, greenish-grey to black,
mucoid and yeast-like, becoming raised and developing tufts of aerial mycelium with
age, often becoming dome-shaped and suede-like in texture. Reverse is olivaceousblack.
Numerous ellipsoidal, yeast-like, budding cells are usually present, especially in
young cultures. Scattered amongst these yeast-like cells are larger, inflated, subglobose
to broadly ellipsoidal cells (germinating cells) which give rise to short torulose hyphae
that gradually change into unswollen hyphae. Conidia are formed on lateral pegs either
arising apically or laterally at right or acute angles from essentially undifferentiated
hyphae or from strongly inflated detached conidia. Conidiogenous pegs are 1-3 µm
long, slightly tapering and imperceptibly annellate. Conidia are hyaline, smooth, thinwalled,
broadly ellipsoidal, 3.2-4.4 x 1.2-2.2 µm, and with inconspicuous basal scars.
Cultures grow at 37 O C but not at 40 O C.
a
5 µm
b
15 µm
5 µm
Exophiala jeanselmei complex showing annellides, conidia and conidiogenous
pegs (annellides) on (a) yeast-like cells and (b) torulose hyphae.
References: de Hoog and Hermanides-Nijhof (1977), de Hoog (1977, 1985), McGinnis
and Padhye (1977), McGinnis (1978b, 1980), Domsch et al. (1980), Nishimura and
Miyaji (1983), Matsumoto et al. (1987), Dixon and Polak-Wyss (1991), Badali et al.
2010, de Hoog et al. (2000, 2003, 2006, 2015).