Aspergillus ustus infections among transplant recipients

Area of Science:

• Mycology
• Infectious Diseases
• Transplant Medicine

Background:

• Aspergillus ustus is a rare mold pathogen, with limited reported human infections.
• Invasive fungal infections pose a significant threat to immunocompromised individuals, particularly hematopoietic stem cell transplant (HSCT) recipients.

Purpose of the Study:

• To report the first outbreak of invasive Aspergillus ustus infection in HSCT recipients.
• To investigate the molecular epidemiology and antifungal susceptibility of A. ustus isolates during the outbreak.

Main Methods:

• Molecular typing using randomly amplified polymorphic DNA (RAPD) analysis.
• Antifungal drug susceptibility testing of clinical and environmental isolates.
• Retrospective case identification and analysis of infection rates and outcomes.

Main Results:

• Six invasive A. ustus infections were identified in HSCT patients between 2001 and 2003.
• The overall attack rate was 1.6%, with a 50% mortality rate occurring rapidly after diagnosis.
• Clinical isolates demonstrated reduced susceptibility to antifungal agents, particularly azoles.
• RAPD and phylogenetic analysis indicated genetic similarity among patient and environmental isolates, suggesting a common source.

Conclusions:

• This study documents the first outbreak of invasive A. ustus infection in HSCT recipients.
• The outbreak was associated with drug-resistant A. ustus strains and a high mortality rate.
• Evidence suggests a potential common-source acquisition, highlighting the need for enhanced surveillance and infection control measures for rare fungal pathogens in vulnerable populations.