TRICHODERMA

SPECIES

MICROSCOPIC APPEARANCE

Hyphae septate, hyaline. Conidiophores hyaline, black. Phialides hyaline, inflated at the base, solitary or in clusters, attached at right angles on the conidiophores. Conidia round or ellipsoidal, smooth walled or rough, often green, in sticky heads at the tips of the phialides.

MACROSCOPIC APPEARANCE

Surface: Texture wooly; white, with scattered greenish tufts, sometimes arranged in concentric rings on surface.
Reverse: Pale or yellowish.
Growth Rate: Rapid to very rapid growth.

DISTINGUISHING FEATURES

Trichoderma species are contaminants occasionally encountered in the clinical laboratory. They are recognized by their wooly white colonies with scattered green tufts, their conidiophores and phialides in a pyramidal network, and their green conidia grouped in sticky heads. A few species with white conidia exist, but are rarely seen in the clinical laboratory.

This genus of fungi in soil furnishes the antibiotic gliotoxin.

HABITAT

Trichoderma are cosmopolitan, saprobes commonly isolated from soil and wood.

PATHOGENICITY

Normally considered nonpathogenic; Usually referred to as a contaminant or allergenic. Nonetheless, Trichoderma viride has been reported form a case of infection of a pulmonary cavity, as well as a case of peritonitis in a dialysis patient and a case of perihepatic infection in a liver transplant patient

RECOMMENDED MEDIA

INCUBATION

Temperature: 25 degrees C.
Time: 2-7 days.

REFERENCES

1. Hensyl, William R. et al. 1990. Stedman's Medical Dictionary , 25th ed. Williams & Wilkins, Baltimore, MD.

2. St. Germain, Guy and Summerbell, Richard, Ph.D. 1996. Identifying Filamentous Fungi , 1st ed. Star Publishing Company, Belmont, CA.

3. Larone, Davise, H. 1995. Medically Important Fungi, A Guide to Identification , 3rd ed. American Society for Microbiology Press, Washington, D.C.

4. The Oxoid Vade-Mecum of Microbiology . 1993. Unipath Ltd., Basingstoke, UK.


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