Opportunistic fungi fail to induce disease in most immunocompetent persons but can do so in those with impaired host defenses. There are five genera of medically important fungi: Candida, Cryptococcus, Aspergillus, Mucor, and Rhizopus.
Rhizopus and Mucor are saprophytic molds but can cause mucormycosis (zygomycosis, phycomycosis) in immunocompromised individuals.
Mycoses can be classified based on the site of the infection, route of acquisition of the pathogen, and type of virulence exhibited by the fungi.
Pneumocystis jirovecii is an opportunistic atypical fungal pathogen which does not respond to conventional anti-fungal agents.
Aspergillus fumigatus is a mold with a septate hyphae with acute angle branching. It causes infections of the skin, eyes and ears; fungus ball in the lungs.
Culture, direct microscopy, and histopathology are mostly used methods for the diagnosis of fungal infections.
Cryptococcus neoformans is an opportunistic fungal pathogen (yeast) responsible for causing cryptococcal meningitis.