Clinical and Microbiological Insights Into Invasive Fusariosis Following Allogeneic Hematopoietic Stem Cell...

Invasive fusariosis (IF) is a rare but often fatal mold infection in immunocompromised patients, particularly after allogeneic hematopoietic stem cell transplantation (HSCT). Despite antifungal prophylaxis and treatment, mortality remains high.

We retrospectively reviewed all allogeneic HSCT recipients for hematological malignancies at our center (2010-2024) and identified proven IF cases. Species identification was based on multigene sequencing, and antifungal susceptibility testing was performed.

Among 2359 allogeneic HSCTs, 17 proven IF cases (7.2/1000) were identified. Patients more often had prior HSCT (58.8% vs. 19.8%, p = 0.002) and were transplanted in non-complete remission (94.1% vs. 75.8%). Median onset was 19 days (range, 2-1011) posttransplant, with a median neutrophil count of 1/µL (range, 1-7097) at diagnosis; 64.7% were pre-engraftment. Prophylaxis included micafungin (n = 10), posaconazole (n = 4), and voriconazole (n = 3). Species: Fusarium solani complex (n = 11), Fusarium dimerum complex (n = 4), and Fusarium fujikuroi complex (n = 2). All isolates had high micafungin MECs (> 16 µg/mL); the median amphotericin B MIC was 4 µg/mL, voriconazole MIC > 8 µg/mL. Median overall survival was 8 days; mortality reached 82.4% by Day 84. In univariate analysis, combination liposomal amphotericin B (L-AMB) plus voriconazole (p = 0.013) and neutrophil recovery (p = 0.008) were associated with improved survival. No clear trends were noted in antifungal susceptibility between survivors and non-survivors.

IF after allogeneic HSCT is rare but highly lethal. Despite the small sample size, outcomes were not clearly associated with MIC values. Early L-AMB plus VRCZ and neutrophil recovery may be associated with improved survival.