Malassezia furfur

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Malassezia furfur
Malassezia furfur (SEM image)

Malassezia furfur ( SEM image)

Systematics
Subdivision : Ustilaginomycotina
Class : Malasseziomycetes
Order : Malasseziales
Family : Malasseziaceae
Genre : Malassezia
Type : Malassezia furfur
Scientific name
Malassezia furfur
( CP Robin ) Baill.

Malassezia (after Louis-Charles Malassez and lat. Furfur "Hautschorf") (old name: Pityrosporum ovale ) is a zoophilic, lipophilic yeast that is provided within the subdivision of smut fungi in the class of exobasidiomycetes. It is thus distantly related to the naked basidia (genus Exobasidium ). Malassezia furfur belongs to the physiologically resident skin flora of humans and occurs in almost 100% of the population. This fungus is one of the few human pathogens from the subdivision of smut fungi , which otherwise almost exclusivelyproduces phytopathogenic representatives. These and other species of the Malassezia genus alsooccur as commensals or parasites in other mammals (e.g. dogs).

morphology

It is a unicellular organism that reaches a size of 1.5 to 5.5 µm and assumes an ellipsoidal to bottle-like shape. Typical “collars” form when the daughter cells sprout. Several yeast cells attached to one another in a chain can develop so-called pseudohyphae.

Way of life

Malassezia furfur is dependent on long-chain fatty acids and therefore prefers skin regions with a sebum-rich environment: these are mainly the hairy scalp , the facial skin and the upper body parts (chest and back). Malassezia yeasts normally live commensally and do not harm their host.

Significance as a pathogen

Malassezia furfur in a skin flake from a patient with pityriasis versicolor

With the appropriate disposition , it can also cause skin diseases , pityriasis versicolor or seborrheic eczema . Both cases are superficial skin infections caused by hyperproliferation of these fungi, i.e. excessive reproduction and overgrowth of the rest of the local flora. Inflammation of the upper (outer) parts of the hair follicles is also possible ( folliculitis ). Malassezia furfur can also cause catheter-associated infections . A role as a provocation factor for atopic eczema is also discussed. Allergic sensitization to Malassezia species is often observed in patients with the latter disease . This can be detected in the blood using the Radio-Allergo-Sorbent Test (RAST).

Taxonomy

The species was first described by Eichstedt in 1846. Due to its morphological diversity ( pleomorphism ), the taxonomy of Malassezia furfur was notoriously controversial and was repeatedly revised . Malassezia furfur was described and renamed more than twenty times between 1853 and 1970.

Systematics

Malassezia furfur belongs to the Basidiomycota class. But only the asexual yeast stage is known. Within the class of the Exobasidiomycetes, the Malasseziales are a small, monotypical order that only contains the Malasseziaceae family and these in turn only the genus Malassezia , in which 13 species are recognized. It is closely related to the Microstomatales within the Exobasidiomycetes. However, a genetic study places the Malasseziales in a class of their own, Malasseziomyetes.

swell

  • Fritz H. Kayser et al .: Medical Microbiology. (9th edition) Thieme, Stuttgart 1998. ISBN 3-13-444809-2 .
  • M. Carmen Aspiroz et al .: Taxonomía de Malassezia furfur: estado de la cuestión. In: Rev Iberoam Micol. (1997) 14 (4). 1997, 147-9. PMID 15538815 .
  • H. Ruth Ashbee, EG Evans: Immunology of Diseases Associated with Malassezia Species. In: Clin Microbiol Rev. 15 (1). 2002, 21-57. PMID 11781265 .

Web links

Commons : Malassezia furfur  - collection of images, videos and audio files

Individual evidence

  1. ↑ a b c d e Cvetomir M. Denchev, Royall T. Moore: Validation of Malasseziaceae and Ceraceosoraceae (Exobasidiomycetes) . In: Mycotaxon . tape 110 , no. 1 , December 30, 2009, p. 379–382 , doi : 10.5248 / 110.379 ( ingenta.com [accessed April 17, 2020]).
  2. ↑ Dominik Begerow, Robert Bauer, Teun Boekhout: Phylogenetic placements of ustilaginomycetous anamorphs as deduced from nuclear LSU rDNA sequences . In: Mycological Research . tape 104 , no. 1 , January 2000, p. 53-60 , doi : 10.1017 / S0953756299001161 ( elsevier.com [accessed April 17, 2020]).
  3. ↑ a b Dominik Begerow, Matthias Stoll, Robert Bauer: A phylogenetic hypothesis of Ustilaginomycotina based on multiple gene analyzes and morphological data . In: Mycologia . tape 98 , no. 6 , November 2006, ISSN  0027-5514 , p. 906-916 , doi : 10.1080 / 15572536.2006.11832620 ( tandfonline.com [accessed April 17, 2020]).
  4. ^ Marianne Abele-Horn: Antimicrobial Therapy. Decision support for the treatment and prophylaxis of infectious diseases. With the collaboration of Werner Heinz, Hartwig Klinker, Johann Schurz and August Stich, 2nd, revised and expanded edition. Peter Wiehl, Marburg 2009, ISBN 978-3-927219-14-4 , p. 285.
  5. ↑ Eichstedt E .: Fungus formation in the Pityriasis versicolor. Frorip New Notes from the Field of Natural History Medicine (1846) 39: 270
  6. ↑ Q.-M. Wang, B. Theelen, M. Groenewald, F.-Y. Bai, T. Boekhout: Moniliellomycetes and Malasseziomycetes, two new classes in Ustilaginomycotina . In: Persoonia - Molecular Phylogeny and Evolution of Fungi . tape 33 , no. 1 , December 10, 2014, p. 41-47 , doi : 10.3767 / 003158514X682313 ( ingenta.com [accessed April 17, 2020]).