There are over 100,000 species of fungi. Many fungi are good and useful (edible mushrooms would be an example of these) while some cause problems (some fungi can injure plants and humans). Every week the IEQ Review will describe a specific microorganism, its morphological origin and potential health effects.  If you would like to know about a specific organism and/or would like it published in The IEQ Review please email Dr. Rajiv Sahay with the Environmental Diagnostics Laboratory (EDL) at Pure Air Control Services laboratory@pureaircontrols.com.

This week we will cover...   

Cryptococcus neoformans  

 
This isolate is urease positive but fails to grow on medium containing cycloheximide or at 40°C. The type strain was isolated from peach juice. It was first described in human medicine in 1894 by Busse who observed the cells in a tumor from the tibia of a woman diagnosed with sarcoma. This species causes disease in both immunocompromised and immunocompetent host. Incidence increased dramatically with the onset of HIV but the leading risk factor for disease is impaired cell mediated immunity .Serodiagnosis of this species breaks it out into one of 5 serotypes, A, B, C, D, and AD. Cryptococcus neoformans var. neoformans (D), C. neoformans var. gattii (B, C), and C. neoformans var. grubii (A). The validity of C. neoformans var. grubii is still being argued and some authors place serotype A as C. neoformans var. neoformans Serotype AD is still being characterized. This species responds well to the azoles but echinocandins are not typically indicated. Interestingly, high MICs to caspofungin are not due to the (1-3)beta-glucan synthase resistance but rather to another mechanism.