C303 - Concurrent Mold and Nontuberculous Mycobacteria Infections in a Hematopoietic Stem Cell Transplant Recipient Undergoing Lung Transplantation for Graft versus Host Disease

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Author Block: L. Akkielah¹, W. Leung², S. Wang³, L. Ataie³, A. Xenocostas⁴, A. Syed⁵, M. Silverman⁶, F. AlMutawa⁷, M. Rahimi Shahmirzadi⁶, ¹Internal Medicine, Infectious Diseases, Transplant Infectious Diseases, Western University, London, ON, Canada, ²Internal Medicine, Infectious Diseases, Western University, London, ON, Canada, ³Western University, London, ON, Canada, ⁴Internal Medicine, Hematology, Bone Marrow Transplantation, Western University, London, ON, Canada, ⁵Infectious Diseases, Transplant Infectious Diseases, University of Toronto, Toronto, ON, Canada, ⁶Internal Medicine, Infectious Diseases Division, Western University, London, ON, Canada, ⁷Pathology and Laboratory Medicine, Western University, London, ON, Canada
*Purpose: To describe the therapeutic challenges of overlapping mold and nontuberculous mycobacteria infections in a hematopoietic stem cell transplant recipient.
*Methods: Detailed review of a 42-year-old woman who underwent allogeneic HSCT for acute myeloid leukemia and later developed severe pulmonary GVHD. Serial imaging, bronchoscopy with cultures and PCR, with therapeutic drug monitoring. Antifungal and antimycobacterial regimens were adjusted based on susceptibility patterns, adverse effects, and drug interactions.
*Results: The patient developed cavitary lung disease five years post-transplant. Bronchoscopy identified Mycobacterium chimaera, Microascus species, and later Aspergillus calidoustus. Initial therapy included voriconazole, liposomal amphotericin B, and a macrolide-based multidrug regimen for NTM. Treatment required multiple modifications for hepatotoxicity, QTc prolongation, and resistance. Despite partial improvement, recurrent mold infection necessitated prolonged antifungal therapy. Progressive bronchiolitis obliterans ultimately required bilateral lung transplantation. Explant pathology showed necrotizing granulomas consistent with treated NTM and invasive mold infection. Post-transplant prophylaxis with voriconazole, rifabutin, azithromycin, inhaled amikacin prevented recurrence.
*Conclusions: Concurrent mold and NTM pulmonary infections in HSCT recipients with GVHD present major diagnostic and therapeutic challenges. This case highlights the need for individualized management incorporating therapeutic drug monitoring, careful navigation of drug interactions, prolonged combination therapy, and the potential value of adjunctive inhaled antifungals. Successful stabilization permitted safe lung transplantation and sustained post-transplant recovery.