DESCRIPTIONS OF MEDICAL FUNGI

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Descriptions of Medical Fungi
Synonymy: Trichophyton ajelloi (Vanbreuseghem) Ajello.
Arthroderma uncinatum is a geophilic fungus with a worldwide distribution which may
occur as a saprophytic contaminant on humans and animals but infections are doubtful.
Not known to invade hair in vivo, but produces hair perforations in vitro.
RG-1 organism.
Arthroderma uncinatum Dawson & Gentles
Morphological Description: Colonies are usually flat, powdery, cream, tan to orangetan
in colour, with a blackish-purple submerged fringe and reverse. Macroconidia
are numerous, smooth, thick-walled, elongate, cigar-shaped, 29-65 x 5-10 µm, and
multiseptate with up to nine or ten septa. Microconidia are usually absent, but when
present are ovate to pyriform in shape.
Key Features: Culture characteristics, macroconidial morphology, urease positive and
good growth on Sabouraud’s 5% salt agar.
Molecular Identification: ITS sequencing recommended (Gräser et al. 2008).
References: Rebell and Taplin (1970), Rippon (1988), de Hoog et al. (2015, 2016).
a
b
20 µm
Arthroderma uncinatum (a) culture and (b) macroconidia.