''Malassezia sympodialis'' is a species in the genus ''

Malassezia ''Malassezia'' (formerly known as ''Pityrosporum'') is a genus of fungi. It is the sole genus in family Malasseziaceae, which is the only family in order Malasseziales, itself the single member of class Malasseziomycetes. ''Malassezia'' species a ...

''. It is characterized by a pronounced lipophily, unilateral, percurrent or

sympodial Sympodial growth is a bifurcating branching pattern where one branch develops more strongly than the other, resulting in the stronger branches forming the primary shoot and the weaker branches appearing laterally. A sympodium, also referred to a ...

budding Budding or blastogenesis is a type of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site. For example, the small bulb-like projection coming out from the yeast cell is know ...

and an irregular, corrugated

cell wall A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mech ...

ultrastructure Ultrastructure (or ultra-structure) is the architecture of cells and biomaterials that is visible at higher magnifications than found on a standard optical light microscope. This traditionally meant the resolution and magnification range of a co ...

. It is one of the most common species found on the skin of healthy and diseased individuals. It is considered to be part of the skin's normal

human microbiota This article lists some of the species recognized as belonging to the human microbiome. Whole-body distributed *''Acinetobacter calcoaceticus'' *'' Burkholderia cepacia'' *''Pseudomonas pseudoalcaligenes'' *''Peptostreptococcus spp'' Natur ...

and begins to colonize the skin of humans shortly after birth. ''Malassezia sympodialis'', often has a

symbiotic Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...

commensal Commensalism is a long-term biological interaction (symbiosis) in which members of one species gain benefits while those of the other species neither benefit nor are harmed. This is in contrast with mutualism, in which both organisms benefit fro ...

relationship with its host, but it can act as a pathogen causing a number of different skin diseases, such as

atopic dermatitis Atopic dermatitis (AD), also known as atopic eczema, is a long-term type of inflammation of the skin (dermatitis). It results in puritis, itchy, red, swollen, and cracked skin. Clear fluid may come from the affected areas, which often thickens o ...

History

In 1846, Karl Ferdinand Eichstedt was the first to identify the association of fungi with

pityriasis versicolor Pityriasis commonly refers to flaking (or scaling) of the skin. The word comes from the Greek πίτυρον "bran". Classification Types include: * Pityriasis alba * Pityriasis lichenoides chronica * Pityriasis lichenoides et varioliformis acut ...

, a common infection associated with the genus ''Malassezia''. The name applied to the fungal agent responsible shifted multiple times over the next 150 years until the genus ''Pityrosporum'' was settled upon for the teleomorph, and ''Malassezia'' for the anamorph. Through the use of genetic sequencing, a number of new species have since been identified.

Description

''Malassezia sympodialis'' exhibits unipolar

, similar to a number of other ''Malassezia'' species including '' M. pachydermatis''. The colonies achieve a size of 5 mm in diameter after a week of growth, and develop a soft texture and a round, smooth shape. The individual cells are oval in shape and 2.5-7.5 × 2.0-8.0 μm in size and acquire a yellowish appearance ''en masse'' when grown in culture at . The optimal growth of this species occurs at . A range of specialized growth media such as Cremophor EL and Leeming-Notman agar that incorporate fatty acids support the growth of ''M. sympodialis''. However, non-specialized growth media overlaid with sterile olive oil also support the growth of this species in culture. ''Malassezia sympodialis'' can be identified in the laboratory by the presence of

β-glucosidase β-Glucosidase (EC 3.2.1.21; systematic name β-D-glucoside glucohydrolase) is an enzyme that catalyses the following reaction: : Hydrolysis of terminal, non-reducing β-D-glucosyl residues with release of β-D-glucose Structure β-Glucosidase ...

activity which causes darkening of the growth medium.

Pathogenicity in humans and animals

The

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