Aspergillus calidoustus and Talaromyces columbinus infections in chronic graft-versus-host disease

Advancements in allogeneic haematopoietic stem cell transplant (alloHSCT) procedures have improved patient outcomes over the last two decades, though invasive fungal infections (IFIs) remain a significant risk. The incidence of IFIs in alloHSCT recipients is estimated at 6%, with a mortality rate of 13%, and Aspergillus species are the most common pathogens involved. Posaconazole is effective in preventing IFIs post-transplant and is standard care during neutropenia or when managing graft-versus-host disease (GvHD) with high-dose steroids. However, azole prophylaxis may cause resistant Aspergillus species like A. calidoustus, which are difficult to treat. We report a case from our institution where a patient developed a dual infection with Aspergillus calidoustus and Talaromyces columbinus after alloHSCT and posaconazole prophylaxis. While A. calidoustus is known to cause IFIs in HSCT recipients, T. columbinus represents a previously unreported occurrence in medical literature. This case underscores the importance of a multifaceted diagnostic strategy, integrating BAL diagnosis, mycological cultures, direct microscopy, fungal speciation, susceptibility testing, and biomarkers. These comprehensive approaches are indispensable for accurate pathogen identification and effective management of IFIs with appropriate antifungal agents.