Cryptococcus neoformans

University of Oklahoma Study Abroad Microbiology in Arezzo, Italy[1]

File:Cdiphtheriametachromatic.jpg

C. diphtheriae bacteria, in green, showing metachromatic granules on the ends of the cell. From: http://textbookofbacteriology.net/diphtheria.html

Classification

Higher order taxa

Eukaryota (Kingdom); Fungi (Domain); Basidiomycota (Phylum); Tremellomycetes (Class); Tremellales (Order); Tremellaceae (Family); Cryptococcus (Genus)

Species

C. neoformans v. neoformans, C. neoformans v. grubii. A third variety, C. neoformans v. gattii, is now considered a distinct species, Cryptococcus gattii.

Description

Cryptococcus neoformans is a fungus that lives in the environment throughout the world. People can become infected with C. neoformans after breathing in the microscopic fungus, although most people who are exposed to the fungus never get sick from it. C. neoformans infections are extremely rare in people who are otherwise healthy; most cases occur in people who have weakened immune systems, particularly those who have advanced HIV/AIDS. In this case, C. neoformans is a leading life-threatening fungal infection.

Pathology

Cryptococcus neoformans is an opportunistic fungal pathogen that may cause meningitis in immunocompromised individuals. Often found in soils contaminated with bird feces, C. neoformans enters its host through the lungs via inhalation of spores. In healthy individuals the infection is usually controlled and asymptomatic, but in immunocompromised hosts the fungus can spread via the blood to infect the central nervous system and cause meningitis that is uniformly fatal if untreated. Few antifungal agents exist and drug-resistant strains are emerging.