Cryptococcus neoformans

Cryptococcus Neoformans

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Cryptococcus neoformans

Cryptococcus neoformans is an encapsulated yeast-like fungus

Fungus

A fungus is a Eukaryote organism that is a member of the Kingdom Fungi . The fungi are a monophyletic group, also called the Eumycota , that is phylogeny distinct from the morphologically similar slime molds and water molds ....
that can live in both plant

Plant

Plants are Life organisms belonging to the Kingdom Plantae. They include familiar organisms such as trees, herbs, bushes, grasses, vines, ferns, mosses, and green algae....
s and animal

Animal

Animals are a major group of multicellular, eukaryotic organisms of the Kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life....
s.This species, also known by its teleomorph name, Filobasidiella neoformans, belongs to the broad class of organisms called "club fungi" or Division Basidiomycota

Basidiomycota

Basidiomycota is one of two large phylum that, together with the Ascomycota, comprise the subkingdom Dikarya within the Kingdom Fungi. More specifically the Basidiomycota include mushrooms, puffballs, stinkhorns, bracket fungi, other polypores, jelly fungi, boletes, cantharellus, Geastraceae, smut , common bunt, rust , mirror yeasts, and the...
, which is one the five major types of fungi. C. neoformans usually grows as a yeast

Yeast

Yeasts are eukaryote microorganisms classified in the Kingdom fungus, with about 1,500 species currently described; they dominate fungal diversity in the oceans....
(unicellular) and replicates by budding

Budding

Budding is the formation of a new organism by the protrusion of part of another organism. This is very common in plants and fungi, but may be found in some animals as well, such as the Hydra ....
. Under certain conditions, both in nature and in the laboratory, C.

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Encyclopedia

Cryptococcus neoformans is an encapsulated yeast-like fungus
Fungus

A fungus is a Eukaryote organism that is a member of the Kingdom Fungi . The fungi are a monophyletic group, also called the Eumycota , that is phylogeny distinct from the morphologically similar slime molds and water molds ....
that can live in both plant
Plant

Plants are Life organisms belonging to the Kingdom Plantae. They include familiar organisms such as trees, herbs, bushes, grasses, vines, ferns, mosses, and green algae....
s and animal
Animal

Animals are a major group of multicellular, eukaryotic organisms of the Kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life....
s.This species, also known by its teleomorph name, Filobasidiella neoformans, belongs to the broad class of organisms called "club fungi" or Division Basidiomycota
Basidiomycota

Basidiomycota is one of two large phylum that, together with the Ascomycota, comprise the subkingdom Dikarya within the Kingdom Fungi. More specifically the Basidiomycota include mushrooms, puffballs, stinkhorns, bracket fungi, other polypores, jelly fungi, boletes, cantharellus, Geastraceae, smut , common bunt, rust , mirror yeasts, and the...
, which is one the five major types of fungi. C. neoformans usually grows as a yeast
Yeast

Yeasts are eukaryote microorganisms classified in the Kingdom fungus, with about 1,500 species currently described; they dominate fungal diversity in the oceans....
(unicellular) and replicates by budding
Budding

Budding is the formation of a new organism by the protrusion of part of another organism. This is very common in plants and fungi, but may be found in some animals as well, such as the Hydra ....
. Under certain conditions, both in nature and in the laboratory, C. neoformans can grow as a filamentous fungus as pictured here: . When grown as a yeast, C. neoformans has a prominent capsule composed mostly of polysaccharides. Microscopically, the India ink
India ink

India ink , or less commonly called Chinese ink since it may have been first developed in either India or China, is a simple black ink once widely used for writing and printing, and now more commonly used for drawing, especially when inking comics and comic strips....
stain is used for easy visualization of the capsule. 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.
The species C. neoformans is composed of three variants (v.): C. neoformans v. gattii, v. grubii, and v. neoformans. C. neoformans v. gattii is found mostly in the tropics
Tropics

The Tropics, seated in the equatorial regions of the world, are limited in latitude by the Tropic of Cancer in the northern hemisphere at approximately 23?26' N latitude, and the Tropic of Capricorn in the southern hemisphere at 23?26' S latitude....
, but has also been confirmed on southern Vancouver Island
Vancouver Island

Vancouver Island is a large island in British Columbia, Canada, one of several North American regions named after George Vancouver, the British Royal Navy officer who explored the Pacific Ocean coast of North America between 1791 and 1794....
on the southwestern coast
Coast

The coast is defined as that part of the land adjoining or near the ocean or its saltwater arms. A precise line that can be called a coastline cannot be determined due to the process of tides....
of Canada
Canada

Canada is a country occupying most of northern North America, extending from the Atlantic Ocean in the east to the Pacific Ocean in the west and northward into the Arctic Ocean....
. Cryptococcus gattii has recently been shown to be different enough from other subspecies to be elevated to its own species level. C. neoformans v. grubii and v. neoformans have a worldwide distribution and are often found in soil which has been contaminated by bird excrement. The genome sequence of C. neoformans v. neoformans was published in 2005. Recent studies suggest that colonies of Cryptococcus neoformans and related fungi growing on the ruins of the melted down
Nuclear meltdown

A nuclear meltdown is a term for a severe nuclear reactor accident. This can occur when a nuclear power plant system or component failure causes the reactor nuclear reactor core to cease being properly controlled and cooled to the extent that the sealed nuclear fuel assemblies – which contain the uranium or plutonium and highly radio...
reactor of the Chernobyl Nuclear Power Plant
Chernobyl Nuclear Power Plant

The Chernobyl Nuclear Power Plant is a nuclear power power plant near the city of Prypiat, Ukraine, 18 km northwest of the city of Chernobyl, 16 km from the border of Ukraine and Belarus, and about 110 km north of Kiev....
may be able to utilize the energy of radiation
Particle radiation

Particle radiation is the radiant energy of energy by means of fast-moving subatomic particles. Particle radiation is referred to as a particle beam if the particles are all moving in the same direction, similar to a light beam....
(primary beta radiation) for "radiotrophic
Radiotrophic fungus

Radiotrophic fungi are a recent discovery, first seen as black molds growing inside and around the Chernobyl Nuclear Power Plant. These fungi appear to use the pigment melanin to convert Gamma rays into chemical energy for growth....
" growth.

Infection with C. neoformans is termed cryptococcosis
Cryptococcosis

'Cryptococcosis' is a serious and potentially fatal fungal disease caused by members of the Cryptococcus neoformans species complex, comprising the two species Cryptococcus neoformans and Cryptococcus gattii with C....
. Meningitis
Meningitis

Meningitis is a medical condition caused by inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges....
, especially as a secondary infection for AIDS
AIDS

Acquired immune deficiency syndrome or acquired immunodeficiency syndrome is a disease of the human immune system caused by the HIV ....
patients, is often caused by C. neoformans.

Treatment
Cryptococcosis that does not affect the central nervous system can be treated with fluconazole
Fluconazole

Fluconazole is a triazole antifungal drug used in the treatment and prevention of superficial and systemic fungal infections. In a bulk powder form, it appears as a white crystalline powder, and it is very slightly soluble in water and soluble in alcohol....
alone.

Cryptococcal meningitis should be treated for two weeks with intravenous Amphotericin B
Amphotericin B

Amphotericin B is a polyene antifungal medication, often used intravenously for systemic fungi infections. It was originally extracted from Streptomyces Streptomyces nodosus, a hypha bacterium, in 1955 at the Squibb Institute for Medical Research from cultures of an undescribed streptomycete isolated from the soil collected in the Orinoc...
0.7–1.0 (mg/kg)/day and oral flucytosine
Flucytosine

Flucytosine, or 5-fluorocytosine, a fluorinated pyrimidine analogue, is a synthetic Antifungal drug drug.It is structurally related to the cytostatic fluorouracil and to floxuridine....
100 (mg/kg)/day (or intravenous flucytosine 75 (mg/kg)/day if the patient is unable to swallow). This should then be followed by oral fluconazole 200mg daily for ten weeks and then 200 mg daily until the patient's CD4
CD4

CD4 is a glycoprotein expressed on the surface of T helper cells, regulatory T cells, monocytes, macrophages, and dendritic cells. It was discovered in the late 1970s and was originally known as leu-3 and T4 before being named CD4 in 1984....
count is above 100 for three months and, if infected, his HIV viral load
Viral load

Viral load is a measure of the severity of a virus infection, and can be calculated by estimating the amount of virus in an involved body fluid....
is undetectable.

Intravenous Ambisome 4 (mg/kg)/day may be used but is not superior: its main use is in patients who do not tolerate Amphotericin B. The 200 (mg/kg)/day dose for flucytosine is not more effective, is associated with more side-effects and should not be used.

In Africa, oral fluconazole at a rate of 200 mg daily is used. However, this does not result in cure because it merely suppresses the fungus and does not kill it; viable fungus can continue to be grown from CSF
Cerebrospinal fluid

Cerebrospinal fluid , Liquor cerebrospinalis, is a clear bodily fluid that occupies the subarachnoid space and the ventricular system around and inside the brain....
of patients who have taken fluconazole for many months. An increased dose of 400 mg daily does not improve outcomes, but preliminary data from Uganda
Uganda

The Republic of Uganda is a landlocked country in East Africa. It is bordered on the east by Kenya, on the north by Sudan, on the west by the Democratic Republic of the Congo, on the southwest by Rwanda, and on the south by Tanzania....
shows that very high doses of 1200 mg or more per day may be effective. The duration of this treatment and the post-treatment maintenance dose is not known.

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