Trichosporon and trichosporonosis

Trichosporon is a genus of anamorphic fungi in the family Trichosporonaceae. All species of Trichosporon are yeasts with no known teleomorphs. 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 known as trichosporonosis in immunocompromised hosts.  Trichosporon species occasionally cause disseminated infections in immunocompromised individuals. Being a part of the natural microbiota of the skin, these Trichosporon spp. can be misdiagnosed as contaminants, resulting in the infection being attributed to dermatophytes, when in fact Trichosporon might be the etiological agent in 10%–40% of superficial infections depending on the geographic area and population. 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, T. asahii, T. mucoides, T. asteroides, and T. cutaneum. The obsolete name T. beigelii was formerly applied to all or any of these species. 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. 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. No teleomorphic or sexual states are known. Trichosporon asahii is an opportunistic fungus that causes infections in immunosuppressed patients. Neutropenia developing due to malignancies is an important risk factor for fungal infection. Combination therapy should be the cornerstone of treatment for trichosporonosis. The combination of high-dose amphotericin B (deoxycholate or liposomal) with either or both 5-flucytosine or voriconazole is commonly prescribed, although failure rates remain high.