DESCRIPTIONS OF MEDICAL FUNGI

Descriptions of Medical Fungi 131
Mucor Micheli ex Staint-Amans
The genus Mucor contains about 50 recognised taxa, many of which have widespread
occurrence and are of considerable economic importance (Zycha et al. 1969, Schipper
1978, Domsch et al. 1980). However, only a few thermotolerant species are of medical
importance and human infections are only rarely reported. Most infections reported
list M. circinelloides and similar species such as M. indicus, M. ramosissimus, M.
irregularis and M. amphibiorum as the causative agents. However, M. hiemalis and
M. racemosus have also been reported as infectious agents, although their inability to
grow at temperatures above 32 O C raises doubt as to their validity as human pathogens
and their pathogenic role may be limited to cutaneous infections (Scholer et al. 1983,
Goodman and Rinaldi 1991, Kwon-Chung and Bennett 1992, de Hoog et al. 2000,
2015).
Maximum temperature for growth of the reported pathogenic species of Mucor.
Species Max temp. ( O C) Pathogenicity
M. amphibiorum 36 Animals, principally amphibians
M. circinelloides 37 Animals, occasionally humans
M. hiemalis 30 Questionable cutaneous infections only
M. indicus 42 Humans and animals
M. irregularis 38 Humans
M. racemosus 32 Questionable
M. ramosissimus 36 Humans and animals
Morphological Description: Colonies are very fast growing, cottony to fluffy, white to
yellow, becoming dark-grey, with the development of sporangia. Sporangiophores are
erect, simple or branched, forming large (60-300 µm in diameter), terminal, globose
to spherical, multispored sporangia, without apophyses and with well-developed
subtending columellae. A conspicuous collarette (remnants of the sporangial
wall) is usually visible at the base of the columella after sporangiospore dispersal.
Sporangiospores are hyaline, grey or brownish, globose to ellipsoidal, and smoothwalled
or finely ornamented. Chlamydospores and zygospores may also be present.
Key Features: Mucorales, large, spherical, non-apophysate sporangia with
pronounced columellae and conspicuous collarette at the base of the columella
following sporangiospore dispersal.
Molecular Identification: ITS sequencing recommended (Walther et al. 2012).
References: Schipper (1978), Domsch et al. (1980), McGinnis (1980), Onions et al.
(1981), Scholer et al. (1983), Rippon (1988), Goodman and Rinaldi (1991), Samson
et al. (1995), de Hoog et al. (2000, 2015), Schipper and Stalpers (2003), Ellis (2005b).