DESCRIPTIONS OF MEDICAL FUNGI

Descriptions of Medical Fungi 117
Molecular Identification: ITS sequencing is recommended for species separation
(Ahmed et al. 2014b, Desnos-Olliver et al. 2006, Irinyi et al. 2015). A five locus
phylogenetic analysis was performed by Ahmed et al. (2014a) using the ITS, D1/D2,
RPB2 and EF-1α genes.
Trematosphaeria grisea (MacKinnon et al.) S.A. Ahmed et al.
Synonymy: Madurella grisea Mackinnon, Ferrada and Montemayer.
RG-2 organism.
Madurella complex
Morphological Description: Colonies are slow growing, dark, leathery, folded
with radial grooves and with a light brown to greyish surface mycelium. With age,
colonies become dark brown to reddish-brown and have a brownish-black reverse.
Microscopically, cultures are sterile, although hyphae of two widths have been
described, thin at 1-3 µm in width or broad at 3-5 µm in width. The optimum temperature
for growth of T. grisea is 30 O C; this fungus does not grow at 37 O C.
Trematosphaeria grisea can be distinguished from Madurella mycetomatis by the
inability to grow at 37 O C and to assimilate lactose.
Key Features: Black grain mycetoma, no growth at 37 O C, no diffusible brown pigment
produced on culture and absence of conidia.
References: McGinnis (1980), Chandler et al. (1980), Rippon (1988), de Hoog et al.
(2000, 2015), Ahmed et al. (2014b), Desnos-Olliver et al. (2006), Irinyi et al. (2015).
100 µm
Trematosphaeria grisea grains (tissue microcolonies) are black, round to
lobed, soft to firm, up to 1.0 mm, with two distinctive zones, a hyaline to
weakly pigmented central zone and a deeply pigmented periphery.