View source for Cryptococcus

{{Short description|Genus of fungi}}
{{For|the genus of scale insects|Cryptococcus (insect)}}
{{Hatnote|Do not confuse Cryptococcus (fungi) with [[Cryptosporidium]] (protists).}}
{{Automatic taxobox
| image = Cryptococcus neoformans using a light India ink staining preparation PHIL 3771 lores.jpg
| image_caption = Yeast state of ''[[Cryptococcus neoformans]]''
| taxon = Cryptococcus (fungus)
| authority = [[Jean Paul Vuillemin|Vuill.]] (1901)
| synonyms =*''Filobasidiella'' {{au|Kwon-Chung (1975)}}
*''Tsuchiyaea'' {{au|Y.Yamada, H.Kawas., Itoh, I.Banno & Nakase (1988)}}
| type_species = ''[[Cryptococcus neoformans]]''
| subdivision_ranks = [[Species]]
| subdivision = see text
}}

'''''Cryptococcus''''' (from [[Ancient Greek]] [[wikt:κρυπτός|κρυπτός]] (''kruptós''), meaning "hidden", and [[wikt:κόκκος|κόκκος]] (''kókkos''), meaning "grain"<ref>https://pmc.ncbi.nlm.nih.gov/articles/PMC2600220/</ref>) is a [[genus]] of [[fungi]] in the [[family (biology)|family]] [[Cryptococcaceae]] that includes both [[yeast]]s and filamentous [[species]]. The filamentous, sexual forms or [[teleomorph]]s were formerly classified in the genus ''Filobasidiella'', while ''Cryptococcus'' was reserved for the yeasts. Most yeast species formerly referred to ''Cryptococcus'' have now been placed in different genera. Some ''Cryptococcus'' species cause a disease called [[cryptococcosis]].

==Taxonomy==
The genus was described by French mycologist [[Jean Paul Vuillemin]] in 1901, when he failed to find [[ascospore]]s characteristic of the genus ''[[Saccharomyces]]'' in the yeast previously known as ''Saccharomyces neoformans''.<ref name="Kurtzman" /> Over 300 additional names were subsequently added to the genus, almost all of which were later removed following [[Molecular phylogenetics|molecular]] research based on [[cladistic]] analysis of [[DNA sequences]]. As a result, some 10 species are recognized in ''Cryptococcus''.<ref name="Liu2015"/>

The teleomorph was first described in 1975 by [[K.J. Kwon-Chung]], who obtained cultures of the [[type species]], ''Filobasidiella neoformans'', by crossing strains of the yeast ''[[Cryptococcus neoformans]]''. She was able to observe [[basidia]] similar to those of the genus ''[[Filobasidium]]'', hence the name ''Filobasidiella'' for the new genus.<ref name="Kwon-Chung"/> 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'' became a synonym of the earlier name ''Cryptococcus''.

==General characteristics==
The cells of species that produce yeasts are covered in a thin layer of glycoprotein capsular material that has a gelatin-like consistency, and that among other functions, serves to help extract nutrients from the soil. The ''C. neoformans'' [[Yeast capsule|capsule]] consists of several polysaccharides, of which the major one is the immunomodulatory polysaccharide called glucuronoxylomannan (GXM).<ref name="Grijpstra2009"/> GXM is made up of the [[monosaccharides]] [[glucuronic acid]], [[xylose]] and [[mannose]] and can also contain O-acetyl groups. The capsule functions as the major virulence factor in cryptococcal infection and disease.<ref name="Casadevall"/>

Some ''Cryptococcus'' species have a huge diversity at the infraspecific level with different molecular types based on their genetic differences, mainly due to their geographical distribution, molecular characteristics, and ecological niches.<ref name="Cogliati2013"/>

''Cryptococcus'' species are not known to produce distinct, visible fruitbodies. All teleomorph forms appear to be parasites of other fungi. In teleomorphs the [[hyphae]] are colourless, are [[clamp connection|clamped]] or unclamped, and bear [[haustoria|haustorial cells]] with filaments that attach to the hyphae of host fungi.<ref name="Findley2009"/><ref name="Ginns&Malloch"/> The [[basidia]] are club-shaped and highly elongated. Spores arise in succession from four loci at the apex (which is sometimes partly septate). These spores are passively released and may remain on the basidium in chains, unless disturbed.<ref name="Kwon-Chung"/> In the type species, the spores germinate to form yeast cells, but yeast states are not known for all species.

==Habitat, distribution and species==
[[File:Cryptococcus.jpg|thumb|right|[[Field stain]] showing ''Cryptococcus'' species in lung tissue]]

'''{{main|Cryptococcus neoformans}}'''
''Cryptococcus neoformans'' is cosmopolitan and is the most prominent medically important species. It is best known for causing a severe form of [[meningitis]] and [[meningoencephalitis]] in people with [[HIV]]/[[AIDS]]. It may also infect [[Organ transplantation|organ-transplant]] recipients and people receiving certain cancer treatments.<ref name="CDC2010" /> In its yeast state ''C. neoformans'' is found in the droppings of wild birds, often [[Columbidae|pigeons]]; when dust of the droppings is stirred up, it can infect humans or pets that inhale the dust. Infected humans and animals do not transmit their infection to others.<ref name="CDC2010" /> The taxonomy of ''C. neoformans'' has been reviewed: it has now been divided into two species: ''Cryptococcus neoformans'' [[sensu stricto]] and ''Cryptococcus deneoformans''.<ref name="Hagen"/><ref name="Liu2015"/>

'''{{main|Cryptococcus gattii}}'''
''Cryptococcus gattii'' (formerly ''C. neoformans'' var. ''gattii'') is endemic to tropical parts of the continent of Africa and Australia. It is capable of causing disease in non-immunocompromised people. In its yeast state it has been isolated from [[eucalyptus]] trees in Australia. The taxonomy of ''C. gattii'' has been reviewed; it has now been  divided into five species: ''C. gattii'' [[sensu stricto]], ''C. bacillisporus'', ''C. deuterogattii'', ''C. tetragattii'', and ''C. decagattii''.<ref name="Hagen"/><ref name="Liu2015"/>

''[[Cryptococcus depauperatus]]'' is parasitic on ''[[Verticillium|Lecanicillium lecanii]]'', an [[entomopathogenic fungus]], and is known from Sri Lanka, England, the Netherlands, the Czech Republic, and Canada.<ref name="Ginns&Malloch"/><ref name="Samson"/> It is not known to produce a yeast state.<ref name="Rodriguez-Carres"/>  This species grows as long, branching filaments and is self-fertile, i.e. it is [[Homothallism|homothallic]].<ref name = Passer2022>{{cite journal|pmid=35713948|pmc=9296135 |date=2022 |last1=Passer |first1=A. R. |last2=Clancey |first2=S. A. |last3=Shea |first3=T. |last4=David-Palma |first4=M. |last5=Averette |first5=A. F. |last6=Boekhout |first6=T. |last7=Porcel |first7=B. M. |last8=Nowrousian |first8=M. |last9=Cuomo |first9=C. A. |last10=Sun |first10=S. |last11=Heitman |first11=J. |last12=Coelho |first12=M. A. |title=Obligate sexual reproduction of a homothallic fungus closely related to the Cryptococcus pathogenic species complex |journal=eLife |volume=11 |doi=10.7554/eLife.79114 |doi-access=free }}</ref> It can reproduce [[sexual reproduction|sexually]] with itself throughout its life cycle.<ref name = Passer2022/>

''[[Cryptococcus luteus]]'' is parasitic on ''[[Granulobasidium vellereum]]'', a [[corticioid]] fungus, and is known from England and Italy.<ref name="Ginns&Bernicchia"/> It too is not known to produce a yeast state.<ref name="Sivakumaran"/>

''[[Cryptococcus amylolentus]]'' was originally isolated as a yeast from beetle tunnels in South African trees. It forms a basidia-bearing teleomorph in culture.<ref name="Findley2012"/>

{{As of|2025|April}}, [[Species Fungorum]] (in the [[Catalogue of Life]]) accept 41 species of ''Cryptococcus'':<ref name="CoL">{{Catalogue of Life |id=CTY7J |title=''Cryptococcus'' |access-date=5 April 2025}}</ref>
* ''[[Cryptococcus amylolentus]]'' {{au|(Van der Walt, D.B.Scott & Klift) Golubev (1981)}}
* ''[[Cryptococcus asgardensis]]'' {{au|Vishniac & Baharaeen (1981)}}
* ''[[Cryptococcus aureus]]'' {{au|(F.C.Harrison) M.Takash., Sugita, Shinoda & Nakase (2003)}}
* ''[[Cryptococcus bacillisporus]]'' {{au|Kwon-Chung & J.E.Benn. (1978)}}
* ''[[Cryptococcus baldrensis]]'' {{au|Vishniac & Baharaeen (1982)}}
* ''[[Cryptococcus cavarae]]'' {{au|Pollacci & Turconi (1929)}}
* ''[[Cryptococcus cellulolyticus]]'' {{au|Nakase, M.Suzuki, Hamam. & M. Takash. (1996)}}
* ''[[Cryptococcus cereanus]]'' {{au|Phaff et al. (1974)}}
* ''[[Cryptococcus consortionis]]'' {{au|Vishniac (1985)}}
* ''[[Cryptococcus decagattii]]'' {{au|F.Hagen & Boekhout (2015)}}
* ''[[Cryptococcus deneoformans]]'' {{au|F.Hagen & Boekhout (2015)}}
* ''[[Cryptococcus depauperatus]]'' {{au|(Petch) Boekhout, Xin Z. Liu, F.Y. Bai & M. Groenew. (2015)}}
* ''[[Cryptococcus deuterogattii]]'' {{au|F.Hagen & Boekhout (2015)}}
* ''[[Cryptococcus elinovii]]'' {{au|Golubev (1979)}}
* ''[[Cryptococcus ferigula]]'' {{au|Saëz & Rodr. Mir. (1988)}}
* ''[[Cryptococcus festucosus]]'' {{au|Golubev & J.P.Samp. (2004)}}
* ''[[Cryptococcus floricola]]'' {{au|Yurkov, A.R. Passer, M.A.Coelho, R.B.Billmyre, M.Nowrousian, Mittelbach, C.A.Cuomo, A.F.Averette, S.Sun & Heitman (2019)}}
* ''[[Cryptococcus gattii]]'' {{au|(Vanbreus. & Takashio) Kwon-Chung & Boekhout (2002)}}
* ''[[Cryptococcus hempflingii]]'' {{au|Vishniac & Baharaeen (1982)}}
* ''[[Cryptococcus heveanensis]]'' {{au|(Groen.) Baptist & Kurtzman (1977)}}
* ''[[Cryptococcus himalayensis]]'' {{au|Goto & Sugiy. (1970)}}
* ''[[Cryptococcus hominis]]'' {{au|Vuill. ex Guég. (1907)}}
* ''[[Cryptococcus lactativorus]]'' {{au|Fell & Phaff (1967)}}
* ''[[Cryptococcus longus]]'' {{au|M.Takash., Sugita, Shinoda & Nakase (2001)}}
* ''[[Cryptococcus lupi]]'' {{au|Baharaeen & Vishniac (1982)}}
* ''[[Cryptococcus luteus]]'' {{au|(P.Roberts) Boekhout, Xin Zhan Liu, F.Y.Bai & M.Groenew. (2015)}}
* ''[[Cryptococcus montanae]]'' {{au|Weijman, Rodr. Mir. & Van der Walt (1988)}}
* ''[[Cryptococcus musci]]'' {{au|M. Takash., Sugita, Shinoda & Nakase (2001)}}
* ''[[Cryptococcus mycelialis]]'' {{au|Golubev & N.W.Golubev (2003)}}
* ''[[Cryptococcus neoformans]]'' {{au|(San Felice) Vuill. (1901)}}
* ''[[Cryptococcus nyarrowii]]'' {{au|Thomas-Hall & K.Watson (2002)}}
* ''[[Cryptococcus pseudolongus]]'' {{au|M.Takash., Sugita, Shinoda & Nakase (2001)}}
* ''[[Cryptococcus ramirezgomezianus]]'' {{au|M.Takash., Sugita, Shinoda & Nakase (2001)}}
* ''[[Cryptococcus saitoi]]'' {{au|Á.Fonseca, Scorzetti & Fell (2002)}}
* ''[[Cryptococcus socialis]]'' {{au|Vishniac (1985)}}
* ''[[Cryptococcus tetragattii]]'' {{au|F.Hagen & Boekhout (2015)}}
* ''[[Cryptococcus tyrolensis]]'' {{au|Vishniac & Baharaeen (1982)}}
* ''[[Cryptococcus uniguttulatus]]'' {{au|(Wolfram & Zach) Phaff & Fell (1970)}}
* ''[[Cryptococcus watticus]]'' {{au|Guffogg, Thomas-Hall, P.Holloway & K.Watson (2004)}}
* ''[[Cryptococcus wingfieldii ]]'' {{au|(Van der Walt, Y.Yamada & N.P.Ferreira) Yurkov, A.R. Passer, M.A.Coelho, R.B.Billmyre, M.Nowrousian, Mittelbach, C.A.Cuomo, A.F.Averette, S.Sun & Heitman (2019)}}
* ''[[Cryptococcus wrightensis]]'' {{au|Vishniac & Baharaeen (1982)}}

==References==
{{Reflist|2|refs=

<ref name="Grijpstra2009">{{cite journal | vauthors = Grijpstra J, Tefsen B, van Die I, de Cock H | title = The ''Cryptococcus neoformans'' cap10 and cap59 mutant strains, affected in glucuronoxylomannan synthesis, differentially activate human dendritic cells | journal = FEMS Immunology and Medical Microbiology | volume = 57 | issue = 2 | pages = 142–50 | date = November 2009 | pmid = 19694810 | doi = 10.1111/j.1574-695X.2009.00587.x | doi-access = free }}</ref>

<ref name="Kwon-Chung">{{cite journal |doi=10.2307/3758842 |author=Kwon-Chung KJ. |year=1975 |title=A new genus, ''Filobasidiella'', the perfect state of ''Cryptococcus neoformans'' |jstor=3758842 |journal=Mycologia |volume=67 |issue= 6|pages=1197–1200 |pmid=765816}}</ref>

<ref name="Kurtzman">{{cite book | url=https://books.google.com/books?id=bnWQsv2eTcEC&dq=%22Saccharomyces+neoformans%22&pg=PA660 | title=The Yeasts - A Taxonomic Study | isbn=978-0-08-054269-0 | last1=Kurtzman | first1=Cletus P. | last2=Fell | first2=Jack W. | date=20 March 1998 | publisher=Elsevier }}</ref>

<ref name="Liu2015">{{cite journal |vauthors=Liu XZ, Wang QM, Göker M, Groenewald M, Kachalkin AV, Lumbsch HT, Millanes AM, Wedin M, Yurkov AM, Boekhout T, Bai FY |year=2015 |title=Towards an integrated phylogenetic classification of the Tremellomycetes |journal=Studies in Mycology |volume=81 |pages=85–147 |doi=10.1016/j.simyco.2015.12.001|pmid=26955199 |pmc=4777781 }}</ref>

<ref name="Casadevall">{{cite book |vauthors=Casadevall A, Perfect JR |year=1998 |title=Cryptococcus neoformans |publisher=American Society for Microbiology, ASM Press}}</ref>

<ref name="Findley2009">{{cite journal |doi=10.1128/EC.00373-08 |vauthors=Findley K, Rodriguez-Carres M, Metin B, Kroiss J, Fonseca A, Vilgalys R, Heitman J |year=2009 |title=Phylogeny and phenotypic characterization of pathogenic ''Cryptococcus'' species and closely related saprobic taxa in the Tremellales |journal=Eukaryotic Cell |volume=8 |issue=3 |pages=353–361 |pmid=19151324 |pmc=2653247}}</ref>

<ref name="Cogliati2013">{{cite journal | vauthors = Cogliati M | title = Global Molecular Epidemiology of ''Cryptococcus neoformans'' and ''Cryptococcus gattii'': An Atlas of the Molecular Types | journal = Scientifica | volume = 2013 | article-number = 675213 | date = 2013 | pmid = 24278784 | pmc = 3820360 | doi = 10.1155/2013/675213 | doi-access = free }}</ref> 
   
<ref name="Samson">{{cite journal |vauthors=Samson RA, Stalpers JA, Weijman AC |year=1983 |title=On the taxonomy of the entomogenous fungus ''Filobasidiella arachnophila'' |journal=Antonie van Leeuwenhoek |volume=49 |issue=4–5 |pages=447–456 |pmid=6651289|doi=10.1007/BF00399323|s2cid=2752286 |url=https://link.springer.com/article/10.1007/BF00399323|url-access=subscription }}</ref>

<ref name="Ginns&Malloch">{{cite journal |doi=10.1007/s11557-006-0051-6 |vauthors=Ginns J, Malloch DW |year=2003 |title=''Filobasidiella depauperata'' (Tremellales): haustorial branches and parasitism of ''Verticillium lecanii'' |journal=Mycological Progress |volume=2 |issue=2 |pages=137–140|bibcode=2003MycPr...2..137G |s2cid=34250983 }}</ref>

<ref name="CDC2010">{{cite web |url=https://www.cdc.gov/healthypets/diseases/crptococcus.htm |title= What is ''Cryptococcus'' infection (cryptococcosis)?|date=April 28, 2010 |publisher= Center for Disease Control and Prevention |access-date=8 March 2012}}</ref>

<ref name="Hagen">{{cite journal |vauthors=Hagen F, Khayhan K, Theelen B, et al |year=2015 |title=Recognition of seven species in the ''Cryptococcus gattii/Cryptococcus neoformans'' species complex |journal=Fungal Genetics and Biology |volume=78 |pages=16–48 |doi=10.1016/j.fgb.2015.02.009|pmid=25721988 |doi-access=free }}</ref>

<ref name="Rodriguez-Carres">{{cite journal |vauthors=Rodriguez-Carres M, Findley K, Sun S, Dietrich FS, Heitman J |year=2010 |title=Morphological and genomic characterization of ''Filobasidiella depauperata'': a homothallic sibling species of the pathogenic ''Cryptococcus'' species complex |journal=PLOS ONE |volume= 5 |issue=3 |doi=10.1371/journal.pone.0009620 |pmc=2835752 |pmid=20224779 |article-number=e9620|bibcode=2010PLoSO...5.9620R |doi-access=free }}</ref>

<ref name="Ginns&Bernicchia">{{cite journal |vauthors=Ginns J, Bernicchia A |year=2000 |title=''Filobasidiella lutea'': parasitism of ''Hypochnicium vellereum'' |journal=Karstenia |volume=40 |issue= 1–2|pages=49–51|doi=10.29203/ka.2000.351 |doi-access=free }}</ref>

<ref name="Sivakumaran">{{cite journal |doi=10.1023/A:1023309311643 |vauthors=Sivakumaran S, Bridge P, Roberts P |year=2002 |title=Genetic relatedness among ''Filobasidiella'' species |journal=Mycopathologia |volume=156 |issue=3 |pages=157–162 |pmid=12749578|s2cid=41798563 }}</ref>

<ref name="Findley2012">{{cite journal |vauthors=Findley K, Sun S, Fraser JA, Hsueh Y, Averette AF, Li W, Dietrich FS, Heitman J |year=2012 |title=Discovery of a modified tetrapolar sexual cycle in ''Cryptococcus amylolentus'' and the evolution of MAT in the ''Cryptococcus'' species complex |journal=PLOS Genetics |volume=8 |issue=2 |article-number=e1002528 |doi=10.1371/journal.pgen.1002528|pmid=22359516 |pmc=3280970 |doi-access=free }}</ref>
}}

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[[Category:Tremellomycetes]]
[[Category:Basidiomycota genera]]
[[Category:Yeasts]]