Taylor Hermann

University of South Florida,
United States of America

Abstract Title: An Unusual Non-Neoformans Cryptococcus in the Lung: Naganishia Diffluens with High Fluconazole Mic and Radiographic Response to Voriconazole

Biography: Dr. Taylor Hermann is an Infectious Diseases fellow at the University of South Florida whose research focuses on medical mycology, transplant infectious diseases, and emerging fungal pathogens. His work includes developing a fungal-risk prediction model for lung-transplant recipients and conducting multi-year outcomes analyses of adenovirus infections at Moffitt Cancer Center. He previously published mechanistic virology research demonstrating how Zika virus induces microcephaly through ribosomal-stress–mediated apoptosis in neuroprogenitor cells.

Research Interest: Cryptococcus species outside the C. neoformans/C. gattii complexes are rarely encountered in human disease, and limited data exist regarding their pathogenicity, optimal treatment, and antifungal susceptibility behavior. Naganishia diffluens—a basidiomycetous yeast previously considered primarily environmental—has only infrequently been documented in clinical infections. We describe a lung-isolated N. diffluens case in an immunocompromised host that demonstrated unusually high fluconazole minimum inhibitory concentrations (MICs) and radiographic response to voriconazole. A middle-aged immunosuppressed patient presented with persistent pulmonary nodules unresponsive to antibacterial therapy. Bronchoalveolar lavage culture and MALDI-TOF MS identified Naganishia diffluens. Histopathology demonstrated granulomatous inflammation with rare encapsulated yeast forms. Susceptibility testing revealed markedly elevated MICs to fluconazole but low MICs to voriconazole and amphotericin B. Serum cryptococcal antigen testing was negative, supporting known reduced antigenicity of non-neoformans species. The patient was treated with oral voriconazole with therapeutic drug monitoring; interval CT imaging showed resolution of nodules and clinical improvement. This case highlights expanding recognition of non-neoformans Cryptococcus species in pulmonary disease, particularly in immunocompromised patients. Lack of antigen detection, atypical radiographic findings, and variable susceptibility patterns present important diagnostic and therapeutic challenges. Species-level identification and MIC-guided therapy are essential for optimal management. Increased awareness and reporting of N. diffluens infections may refine future guidance on antifungal selection and duration.