All of the following are true regarding Cryptococcus neoformans except: September 2008

Ans. D: Anticapsular antibody is protective C neoformans reproduces by budding and forms round yeast like cells that are 3-6 um in diameter. Within the host and in ceain culture media, a large polysaccharide capsule surrounds each cell. C neoformans forms smooth, convex, yellow or tan colonies on solid media at 20-37degC (68-98.6degF). This fungus is identified based on its microscopic appearance, biochemical test results, and ability to grow at 37degC (98.6degF); most nonpathogenic Cryptococcus strains do not grow at this temperature. In addition, C. neoformans does not assimilate lactose and nitrates or produce pseudomycelia on cornmeal or rice-Tween agar. Most infections with C. neoformans consist of a lung infection.However, fungal meningitis, especially as a secondary infection for AIDS patients, is often caused by C. neoformans making it a paicularly dangerous fungus. Infections with this fungus are rare in those with fully functioning immune systems Blood and CSF should be cultured for fungi and submitted for cryptococcal antigen testing whenever CNS infection is suspected. Colonies on Sabouraud dextrose agar at 25degC are cream to beige and mucoid due to the capsule surrounding the yeast cells.