Leveduras e fungos

Aspergillus fumigatus

Septate, hyaline filamentous fungus

Identification & Growth

Identification

Septate hyaline hyphae with acute-angle (45°) branching
Conidiophore with a columnar vesicle and uniseriate phialides; grey-green colony

Growth Conditions

Sabouraud agar without cycloheximide; grows at 48 °C, 48–72 h

Clinical Significance

Invasive pulmonary aspergillosis, aspergilloma, sinusitis and otomycosis

Intrinsic Resistance

Resistant to fluconazole; echinocandin monotherapy has only fungistatic, not fungicidal, activity

Bench Alerts

Voriconazole is first-line; consider azole resistance in cases of treatment failure
Isolation from a respiratory sample in an immunosuppressed patient should be reported alongside galactomannan results

Clinical Notes

Clinical presentations

Invasive pulmonary aspergillosis in neutropenic and transplant patients, with nodules, halo sign and haemoptysis.
Chronic pulmonary aspergillosis and aspergilloma in residual cavities, typically post-tuberculosis.
Allergic bronchopulmonary aspergillosis in asthma and cystic fibrosis, and aspergillosis associated with influenza or severe viral disease.

Specimens and collection

Bronchoalveolar lavage for culture, microscopy and galactomannan; blood culture is almost always negative.
Biopsy with histopathology demonstrates tissue invasion and separates colonization from invasive disease.
Serial serum galactomannan is useful for monitoring high-risk haematology patients.

Epidemiology and at-risk populations

Conidia are inhaled daily from the environment; construction work and contaminated air systems increase hospital exposure.
Highest risk in prolonged neutropenia, stem-cell or solid-organ transplantation, high-dose corticosteroids and chronic granulomatous disease.
Environmentally acquired azole resistance, linked to agricultural fungicide use, is expanding globally.

Resistance and therapeutic implications

Voriconazole and isavuconazole are first-line for invasive disease, per international guidelines.
cyp51A mutations (for example TR34/L98H) confer azole resistance and should be suspected in treatment failure.
Aspergillus is intrinsically resistant to fluconazole; echinocandins have only partial activity and an adjunctive role.

Bench and reporting notes

Hyaline septate hyphae with acute-angle (~45°) branching on direct microscopy with KOH or calcofluor.
Blue-green colonies with a pale reverse; growth at 48 °C distinguishes A. fumigatus from other species.
Handle plates in a biological safety cabinet and avoid opening sporulating cultures on the open bench.

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 Aspergillus fumigatus in the lab?

Aspergillus fumigatus is identified through septate hyaline hyphae with acute-angle (45°) branching, conidiophore with a columnar vesicle and uniseriate phialides; grey-green colony.

What are the intrinsic resistances of Aspergillus fumigatus?

This organism is naturally resistant to resistant to fluconazole; echinocandin monotherapy has only fungistatic, not fungicidal, activity. These drugs should not be reported as susceptible.

Where is Aspergillus fumigatus commonly found?

It is typically associated with invasive pulmonary aspergillosis, aspergilloma, sinusitis and otomycosis.

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