Medical significance of the so-called black yeasts

Abstract

Infections caused by the black yeasts (leveduras pretas) are reviewed with respect to their clinical manifestations, classification under the umbrella term, phaeohyphomycosis, and differentiation from chromoblastomycosis. Data on the prevalence of black yeasts submitted to a national reference diagnostic center are provided. Cases of phaeohyphomycosis caused by Aureobasidium pullulans, Exophiala jeanselmei, E. moniliae, E. spinifera, Phaeoannelomyces werneckii, Phaeosclera dematioides, Sarcinomyces phaeomuriformis, and Wangiella dermatitidis are described.

Black Yeasts and Their Filamentous Relatives: Principles of Pathogenesis and Host Defense

“…The term "black yeasts" indicates those melanized fungi that are able to reproduce in culture by unicellular budding (yeast-like cells) (3,28). Not all members of the group causing infection have this ability, and therefore the fungi are united on the basis of phylogenetic relationships.…”

“…They also have been reported in cold-blooded vertebrates, with a wide variety of clinical features (4). Black yeasts multiply by budding (i.e., produce yeast-like cells) in certain stages of their development or under certain environmental conditions, and their colonies are pasty with some shade of black, while their filamentous relatives are strictly hyphal (3). However, these fungi are united on the basis of phylogenetic relationships.…”

“…In phaeohyphomycosis, however, the fungi characteristically occur as dark, septate hyphal elements or catenulate cells (toruloid hyphae). Mycetoma and phaeohyphomycosis result in tissue necrosis, whereas chromoblastomycosis infections lead to excessive proliferation of host tissue (3).…”

Generation of Indole Alkaloids in the Human‐Pathogenic Fungus Exophiala dermatitidis

“…[2] E. dermatitidis serves as the model of choice for discovering cell wall-related virulence determinants. [3] The biosynthesis of 1,8-dihydroxynaphthalene melanin in particular has been studied in detail in E. dermatitidis, [4] since this compound contributes to its pathogenicity.…”

Genome Sequence of Aureobasidium pullulans AY4, an Emerging Opportunistic Fungal Pathogen with Diverse Biotechnological Potential

“…However, in 1910, a new taxonomic combination under A. pullulans was proposed (7). A. pullulans has been regarded as having various biotechnology and environmentrelated applications, such as production of extracellular polymeric substances, especially pullulan, production of hydrolytic enzymes, including amylases, proteases, esterases, pectinases, xylanases, and mannanases (3,8), and as a biocontrol agent for plants (9).…”