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Rasamsonia argillacea brain abscess in a lung transplant recipient: an unexpected infection by an unusual fungal pathogen

Summary

A 65-year-old woman who received a lung transplant developed a serious brain infection caused by a rare fungus called Rasamsonia argillacea. Doctors initially struggled to identify this unusual fungus and treated her with multiple antifungal medications, but the infection proved difficult to control because the fungus was resistant to common antifungal drugs. Investigations revealed that the patient had an undiagnosed immune system disorder called chronic granulomatous disease, which made her vulnerable to this rare infection. Despite aggressive treatment including surgery and powerful antifungal medications, the patient’s condition worsened and she eventually passed away.

Background

Rasamsonia argillacea is a rare thermotolerant fungal pathogen that has emerged as an opportunistic infection primarily in immunocompromised patients, particularly those with chronic granulomatous disease. While Aspergillus species are the most common fungal infections post-lung transplantation, rare and emerging molds are increasingly recognized. This case presents an unusual presentation of R. argillacea brain abscess in a lung transplant recipient without prior fungal colonization.

Objective

To report a case of Rasamsonia argillacea brain abscess in a lung transplant recipient and highlight the unique characteristics and diagnostic challenges associated with this unusual pathogen. The case demonstrates the importance of considering rare molds in atypical post-transplant infections and prompting immunological investigation when standard risk factors are absent.

Results

Culture and molecular sequencing confirmed Rasamsonia argillacea from cerebral abscess fluid, along with concurrent Aspergillus udagawae and Aspergillus nomius from lung and skin biopsies respectively. Susceptibility testing showed R. argillacea had high MIC to voriconazole (>16 mg/L) and isavuconazole (>8 mg/L), but lower MIC to posaconazole and echinocandins. Immunological assessment revealed a homozygous deletion in NCF1 gene compatible with chronic granulomatous disease diagnosis at age 65.

Conclusion

This is the first reported case of Rasamsonia cerebral abscess in a lung transplant recipient without pretransplant fungal colonization. The unusual nature of this pathogen prompted investigation that led to the diagnosis of previously unsuspected chronic granulomatous disease, highlighting the importance of considering rare molds in atypical post-transplant infections and the need for comprehensive immunological assessment.
  • Published in:Medical Mycology Case Reports,
  • Study Type:Case Report,
  • Source: PMID: 41050733; DOI: 10.1016/j.mmcr.2025.100727
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