Leveduras e fungos

Trichosporon asahii

Yeasts with arthroconidia

Identification & Growth

Identification

Urease-positive, arthroconidia and blastoconidia seen on microculture
May cause a false-positive cryptococcal antigen and galactomannan test

Growth Conditions

Sabouraud agar 30–35 °C, 48–72 h; dry, cerebriform colonies

Clinical Significance

Fungemia in neutropenic patients, catheter infection, white piedra

Intrinsic Resistance

Resistant to echinocandins; amphotericin B has limited activity

Bench Alerts

Voriconazole is the drug of choice
Never report caspofungin as susceptible

Clinical Notes

Clinical presentations

Breakthrough fungemia in neutropenic patients on echinocandin prophylaxis, with high lethality.
Disseminated infection with papulonodular skin lesions and pulmonary and renal involvement.
White piedra (superficial hair infection) and catheter-associated urinary infection in less severe patients.

Specimens and collection

Blood culture (positive reasonably often, unlike filamentous fungi) and biopsy of skin lesions.
Urine and catheter tip according to the suspected focus, always with clinical correlation.
Request species-level yeast identification whenever fungemia occurs in an immunosuppressed patient.

Epidemiology and at-risk populations

Environmental yeast found in soil, water and as a transient colonizer of skin and the gastrointestinal tract.
It is the most frequent cause of invasive trichosporonosis, mainly in haematological malignancy and profound neutropenia.
Invasive devices, corticosteroids and mucosal barrier breakdown complete the risk profile.

Resistance and therapeutic implications

Intrinsic resistance to echinocandins (caspofungin, micafungin, anidulafungin) — never report them as an option.
Reduced amphotericin B susceptibility; triazoles, especially voriconazole, are the mainstay of therapy.
Catheter removal and neutropenia recovery influence outcome as much as the antifungal itself.

Bench and reporting notes

It produces arthroconidia, blastoconidia, hyphae and pseudohyphae — a combination that separates it from Candida on microscopy.
Urease-positive; it may cause a false-positive cryptococcal antigen test through galactoxylomannan cross-reactivity.
Include the intrinsic echinocandin-resistance alert in the report, because it immediately changes empirical therapy.

Sources

Educational decision-support content. It does not replace laboratory validation, current guidelines or review by the responsible professional.

FAQ: Frequently Asked Questions

How to identify Trichosporon asahii in the lab?

Trichosporon asahii is identified through urease-positive, arthroconidia and blastoconidia seen on microculture, may cause a false-positive cryptococcal antigen and galactomannan test.

What are the intrinsic resistances of Trichosporon asahii?

This organism is naturally resistant to resistant to echinocandins; amphotericin b has limited activity. These drugs should not be reported as susceptible.

Where is Trichosporon asahii commonly found?

It is typically associated with fungemia in neutropenic patients, catheter infection, white piedra.

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