Cryptococcus neoformans was the first intracellular pathogen for which the non-lytic escape process termed vomocytosis was observed. It is a facultative intracellular pathogen that can utilize host phagocytes to spread within the body. neoformans is often referred to as an opportunistic pathogen. Infections with this fungus are rare in people with fully functioning immune systems, hence C. neoformans, making it a particularly dangerous fungus. However, fungal meningitis and encephalitis, especially as a secondary infection for AIDS patients, are often caused by C. neoformans and related fungi growing on the ruins of the melted down reactor of the Chernobyl nuclear power plant may be able to use the energy of radiation for " radiotrophic" growth. The first genome sequence for a strain of C. Cryptococcal antigen from cerebrospinal fluid is thought to be the best test for diagnosis of cryptococcal meningitis in terms of sensitivity, though it might be unreliable in HIV-positive patients. For identification in tissue, mucicarmine stain provides specific staining of polysaccharide cell wall in C. Unusual morphological forms are rarely seen. This allows for quick and easy identification of C. The particles of ink pigment do not enter the capsule that surrounds the spherical yeast cell, resulting in a zone of clearance or "halo" around the cells. Under the microscope, the India ink stain is used for easy visualization of the capsule in cerebral spinal fluid. neoformans has a prominent capsule composed mostly of polysaccharides. In such stained preparations, it may appear either as round cells with Gram-positive granular inclusions impressed upon a pale lavender cytoplasmic background or as Gram-negative lipoid bodies. neoformans in Gram-stained smears of purulent exudates may be hampered by the presence of the large gelatinous capsule which apparently prevents definitive staining of the yeast-like cells. Under host-relevant conditions, including low glucose, serum, 5% carbon dioxide, and low iron, among others, the cells produce a characteristic polysaccharide capsule. It makes hyphae during mating, and eventually creates basidiospores at the end of the hyphae before producing spores. ( February 2020) ( Learn how and when to remove this template message)Ĭryptococcus neoformans typically grows as a yeast (unicellular) and replicates by budding. Please help improve it to make it understandable to non-experts, without removing the technical details. This section may be too technical for most readers to understand.
#India ink staining crytpococcois code
Following changes to the International Code of Nomenclature for algae, fungi, and plants, the practice of giving different names to teleomorph and anamorph forms of the same fungus was discontinued, meaning that Filobasidiella neoformans became a synonym of the earlier name Cryptococcus neoformans. She was able to observe basidia similar to those of the genus Filobasidium, hence the name Filobasidiella for the new genus. Kwon-Chung, who obtained cultures of Filobasidiella neoformans by crossing strains of the yeast C. The teleomorph was first described in 1975 by K.J. A new species name, Cryptococcus deneoformans, is used for the former C. The most recent classification system divides these varieties into seven species. gattii, was later defined as a distinct species, Cryptococcus gattii. Classification Ĭryptococcus neoformans has undergone numerous nomenclature revisions since its first description in 1895. Cryptococcus neoformans can cause disease in apparently immunocompetent, as well as immunocompromised, hosts. In its yeast state, it is often found in bird excrement. Its teleomorph is a filamentous fungus, formerly referred to Filobasidiella neoformans. Saccharomyces neoformans San Felice (1895)įilobasidiella neoformans Kwon-Chung (1975)Ĭryptococcus neoformans is an encapsulated yeast belonging to the class Tremellomycetes and an obligate aerobe that can live in both plants and animals.
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