Invasive Aspergillosis Due to Aspergillus Section Usti: A Multicenter Retrospective Study

Area of Science:

• Medical Mycology
• Infectious Diseases
• Clinical Microbiology

Background:

• Aspergillus ustus (A. ustus) is a rare cause of invasive aspergillosis (IA).
• Epidemiology and outcomes of A. ustus infections are not well-characterized.

Purpose of the Study:

• To describe the epidemiology and outcomes of invasive aspergillosis caused by Aspergillus ustus.
• To identify risk factors and treatment strategies for A. ustus infections.

Main Methods:

• Retrospective multicenter study involving 22 hospitals across 8 countries.
• Species identification via BenA/CaM sequencing and antifungal susceptibility testing.
• Literature review to identify additional cases, classifying infections by standard criteria.

Main Results:

• 72 proven/probable IA cases identified, predominantly in transplant recipients (47% HCT, 33% SOT).
• Most patients were nonneutropenic (92%) with frequent extrapulmonary involvement (46%), including skin (28%).
• High 24-week mortality (58%) observed; Aspergillus calidoustus was the most frequent species.

Conclusions:

• Aspergillus ustus IA predominantly affects nonneutropenic transplant patients and often presents with extrapulmonary disease.
• High mortality rates underscore the need for optimized antifungal therapies.
• Antifungal susceptibility data indicate variable efficacy, with high MIC90 for posaconazole.