Trichosporon

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Trichosporon
Scientific classification
Kingdom: Fungi
Phylum: Basidiomycota
Subphylum: Agaricomycotina
Class: Tremellomycetes
Order: Tremellales
Family: Trichosporonaceae
Genus: Trichosporon
Behrend
Type species
Trichosporon beigelii
(Küchenm. & Rabenh.) Vuill.
Other species

Trichosporon aquatile
Trichosporon asahii
Trichosporon asteroides
Trichosporon brassicae
Trichosporon caseorum
Trichosporon chiarellii
Trichosporon coremiiforme
Trichosporon cutaneum
Trichosporon debeurmannianum
Trichosporon dehoogii
Trichosporon dermatis
Trichosporon dohaense
Trichosporon domesticum
Trichosporon dulcitum
Trichosporon faecale
Trichosporon gamsii
Trichosporon gracile
Trichosporon guehoae
Trichosporon inkin
Trichosporon insectorum
Trichosporon japonicum
Trichosporon jirovecii
Trichosporon lactis
Trichosporon laibachii
Trichosporon lignicola
Trichosporon loubieri
Trichosporon moniliiforme
Trichosporon montevideense
Trichosporon mucoides
Trichosporon multisporum
Trichosporon ovoides
Trichosporon porosum
Trichosporon scarabaeorum
Trichosporon sinense
Trichosporon smithiae
Trichosporon sporotrichoides
Trichosporon terricola
Trichosporon tryphenardum
Trichosporon vadense
Trichosporon vanderwaltii[1]
Trichosporon veenhuisii
Trichosporon wilphenae

Trichosporon is a genus of anamorphic fungi in the family Trichosporonaceae. All species of Trichosporon are yeasts with no known teleomorphs (sexual states). Most are typically isolated from soil, but several species occur as a natural part of the skin microbiota of humans and other animals. Proliferation of Trichosporon yeasts in the hair can lead to an unpleasant but non-serious condition known as white piedra. Trichosporon species can also cause severe opportunistic infections (trichosporonosis) in immunocompromised individuals.

Taxonomy[edit]

The genus was first described by the German dermatologist Gustav Behrend in 1890, based on yeasts isolated from the hairs of a moustache where they were causing the condition known as "white piedra".[2] Behrend called his new species T. ovoides, but subsequently Pleurococcus beigelii (later recombined as Trichosporon beigelii) was considered to be an earlier name for the same species and was accepted as the type of the genus Trichosporon.

Over 100 additional yeast species were referred to Trichosporon by later authors.[3] With the advent of DNA sequencing, however, it became clear that many of these additional species belonged in other genera. Based on cladistic analysis of DNA sequences, just under 40 species are now accepted in the genus.[4]

DNA sequencing has also shown that white piedra can be caused by more than one Trichoporon species. As a result, Trichosporon beigelii has become a name of uncertain application. McPartland & Goff selected a neotype strain that makes T. beigelii synonymous with Trichosporon cutaneum.[5][6] Guého and others, however, have argued that T. beigelii should be discarded (as a dubious name) and Behrend's original T. ovoides (for which a neotype strain has also been selected) should become the type.[2] As a result of this uncertainty, the name T. beigelii is now obsolete.[7]

Description and habitat[edit]

Trichosporon species are distinguished microscopically by having yeast cells that germinate to produce hyaline hyphae that disarticulate at the septa, the hyphal compartments acting as arthroconidia (asexual propagules). No teleomorphic (sexual) states are known.

Species are widespread and have been isolated from a wide range of substrates, including human hair (Trichosporon ovoides), soil (T. guehoae), cabbages (T. brassicae), cheese (T. caseorum), scarab beetles (T. scarabaeorum), parrot droppings (T. coremiiforme), and sea water (T. dermatis).[4]

Human pathogens[edit]

Several Trichosporon species occur naturally as part of the microbiota of human skin. Occasionally, particularly in circumstances of high humidity, the fungus can proliferate, causing an unpleasant but harmless hair condition known as white piedra. Soft, pale nodules containing yeast cells and arthroconidia form on hairs of the scalp and body. The species responsible include Trichosporon ovoides, T. inkin,[8] T. asahii, T. mucoides, T. asteroides, and T. cutaneum. The obsolete name T. beigelii was formerly applied to all or any of these species.[9]

Much more serious opportunistic infections, collectively called trichosporonosis, have been reported in immunocompromised individuals. Species said to be agents of trichosporonosis are T. asahii, T. asteroides, T. cutaneum, T.dermatis, T. dohaense, T. inkin, T. loubieri, T. mucoides, and T. ovoides.[10][11][12]

References[edit]

  1. ^ Motaung, Thabiso E.; Albertyn, Jacobus; Kock, Johan L. F.; Lee, Ching-Fu; Suh, Sung-Oui; Blackwell, Meredith; Pohl, Carolina H. "Trichosporon vanderwaltii sp. nov., an asexual basidiomycetous yeast isolated from soil and beetles". Antonie van Leeuwenhoek 103 (2): 313–319. doi:10.1007/s10482-012-9811-2. 
  2. ^ a b Guého E, de Hoog GS, Smith MT. (1992). "Neotypification of the genus Trichosporon". Antonie van Leeuwenhoek 61 (4): 285–288. PMID 1497333. 
  3. ^ "Genus Record Details-Trichosporon". Index Fungorum. CAB International. Retrieved 2010-04-30. 
  4. ^ a b Middelhoven WJ, Scorzetti G, Fell JW. (2004). "Systematics of the anamorphic basidiomycetous yeast genus Trichosporon Behrend with the description of five novel species". International Journal of Systematic and Evolutionary Microbiology 54 (Pt 3): 975–986. doi:10.1099/ijs.0.02859-0. PMID 15143052. 
  5. ^ McPartland JM, Goff JP. (1991). "Neotypification of Trichosporon beigelii: morphological, pathological and taxonomic considerations". Mycotaxon 41: 173–178. 
  6. ^ http://www.cbs.knaw.nl/Yeast/BioloMICS.aspx?Link=T&DB=0&Table=0&Descr=CBS%202466&Fields=All&ExactMatch=T
  7. ^ Mycology Online: Trichosporon asahii http://www.mycology.adelaide.edu.au/virtual/2008/ID2-Apr08.html
  8. ^ Magalhães AR, Bona de Mondino SS, da Silva M, Nishikawa MM. (2008). "Morphological and biochemical characterization of the aetiological agents of white piedra". Mem. Inst. Oswaldo Cruz 103 (8): 786–790. doi:10.1590/s0074-02762008000800008. PMID 19148418. 
  9. ^ Schwartz RA, Altman R. eMedicine: Piedra http://emedicine.medscape.com/article/1092330-overview
  10. ^ Sugita T, Nishikawa A, Shinoda T (1998). "Rapid detection of species of the opportunistic yeast Trichosporon by PCR". Journal of Clinical Microbiology 36 (5): 1458–1460. PMC 104855. PMID 9574732. 
  11. ^ Marty FM, Barouch DH, Coakley EP, Baden LR. (2003). "Disseminated trichosporonosis caused by Trichosporon loubieri". Journal of Clinical Microbiology 41 (11): 5317–5320. doi:10.1128/JCM.41.11.5317-5320.2003. PMC 262469. PMID 14605194. 
  12. ^ Taj-Aldeen SJ, Al-Ansari N, El Shafei S, Meis JF, Curfs-Breuker I, Theelen B, Boekhout T. (2009). "Molecular identification and susceptibility of Trichosporon species isolated from clinical specimens in Qatar: Isolation of Trichosporon dohaense Taj-Aldeen, Meis & Boekhout sp. nov.". Journal of Clinical Microbiology 47 (6): 1791–1799. doi:10.1128/JCM.02222-08. PMC 2691106. PMID 19321719. 

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