The Trichosporon species have recently
emerged as significant systemic pathogens in immunocompromised patients.
These yeastlike fungi are soil saprophytes that also form a minor
component of normal skin flora.
T. beigelii (
Syn: T. cutaneum ), is
a frequent pathogen and is better known as the agent of white piedra, a nodule-forming trichomycosis.
(i) Trichosporon
cutaneum & Trichosporon asteroides
(Superficial
cutaneous infections)
(ii) Trichosporon
ovoides
[ White piedra (scalp) ]
;
Trichosporon inkin
[White piedra
(pubic)].
(iii)
Trichosporon asahii (common) & Trichosporon mucoides
(Systemic
trichosporonosis)
Disseminated trichosporonosis occurs principally in patients who are neutropenic as
a result of treatment for acute leukemia, lymphoma, or solid tumours
but it has also been reported in immunosuppressed transplant
recipients.
Purpuric cutaneous nodules are a frequent clinical
manifestation, and the lungs, kidneys, myocardium, liver, spleen, and
bone marrow are also frequently involved.
Systemic lesions consist of
abscesses, granulomas, or nodular infarcts, the last a consequence of
mycotic vascular invasion and occlusion.
In tissue
sections, the Trichosporon spp can be recognized as pleomorphic
blastoconidia , 3 to 8 micrometer in diameter, septate hyphae, and
arthroconidia that are produced by fragmentation of hyphal segments.
These fungi may be difficult to distinguish from some other
opportunistic pathogen, such as the Candida species, if arthroconidia are inconspicuous.
A presumptive histologic diagnosis of
trichosporonosis is therefore best confirmed by culture or
immunoflourescence.
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