is a dematiaceous filamentous fungus isolated from soil, air, and from decomposing plant
debris, especially woody or straw – like materials and from herbivore dung. Aside from being
a contaminant, Chaetomium species are also encountered as causative agents of
infections in humans. Additionally, some species are thermophilic and neurotropic in nature.
The genus Chaetomium
contains a number of species. The most widespread ones are Chaetomium atrobrunneum,
Chaetomium funicola, Chaetomium globosum, and Chaetomium strumarium.
Pathogenicity and Health Effects
species are among the fungi causing infections referred to as
phaeohyphomycosis. Cases of fatal deep mycoses in an immunocompromised patient due
to Chaetomium atrobrunneum have been reported.
lesions, and onychomycosis may also develop due to Chaetomium species.
rate is rapid and colony texture is cottony; and
Ø Surface colony color is white initially but as colonies mature, color becomes gray to olive
while tan to red or brown to black on the reverse.
hyaline to pale brown;
ascospores are present;
Perithecia are brown to black in color, large, fragile, globose to flask –
shaped and surrounded by long, undulant, helical or erect, spine – like
filamentous setae (hair – like appendages);
Perithecia have small rounded openings called
ostioles which contain asci
and ascospores inside;
are clavate to cylindrical in shape and remain intact only for a short
period of time after their formation (evanescent) and dissolve rapidly to
release their ascospores which are usually four to eight in number;
Ascospores are unicellular, brown in color, and usually lemon – shaped.
Only general laboratory
precautions are required, no special safety measures needed.
There is no standard
method for in vitro susceptibility testing of Chaetomium species as yet and very
few data are available. When a small number of Chaetomium atrobrunneum, Chaetomium
funicola, and Chaetomium globosum isolates were tested, it appears that MICs of
miconazole were acceptably low while those of
appeared very high.