Concurrent Mold, Mycobacterial, and Viral Infections in a Hematopoietic Stem Cell Transplant Recipient Undergoing Lung Transplantation for Graft-Versus-Host Disease.

Hematopoietic stem cell transplant (HSCT) recipients are at high risk for opportunistic infections due to profound immunosuppression and graft-versus-host disease (GvHD). Molds and nontuberculous mycobacteria (NTM) pose diagnostic and therapeutic challenges, especially when infections overlap. A 42-year-old woman with prior allogeneic HSCT for acute myeloid leukemia (AML) developed pulmonary infections with Microascus spp. and Mycobacterium chimaera, later complicated by Aspergillus calidoustus and RSV infection. Initial therapy included voriconazole, amphotericin B, and a macrolide-based multidrug regimen for NTM. Modifications were required for drug resistance and hepatotoxicity. Despite partial response, recurrent fungal infection necessitated prolonged antifungal therapy, including adjunctive inhaled amphotericin B and terbinafine. Ultimately, progressive bronchiolitis obliterans prompted bilateral lung transplantation. Explant pathology revealed necrotizing granulomas positive for NTM and Microascus spp. Post-transplant prophylaxis with voriconazole, rifabutin, azithromycin, and inhaled amikacin prevented recurrence, and the patient remained clinically stable at 6-month follow-up. This case illustrates the complexity of managing overlapping mold and NTM infections in HSCT recipients, highlighting the need for individualized, multidisciplinary care. Therapeutic drug monitoring, careful adjustment for drug-drug interactions, and the use of adjunctive inhaled antifungals were critical to achieving a favorable outcome.