A Threat Emerging in Patients with Hematological Malignancy: Invasive Magnusiomyces capitatus and Magnusiomyces clavatus Infections.

Background: Magnusiomyces capitatus (M. capitatus) and Magnusiomyces clavatus (M. clavatus) are rare cause of fungemia leading to high mortality rates, particularly in neutropenic patients with hematological malignancies. This research set out to explore the clinical characteristics of patients with hematological malignancies with M. capitatus and M. clavatus fungemia. Methods: Eight patients from whom Magnusiomyces spp. were isolated, from among patients hospitalized at the Atatürk University Hospital between October 2017 and November 2022, were enrolled in this retrospective observational study. The 8 patients' medical data were subjected to analysis. Results: Magnusiomyces capitatus emerged as the pathogen in 5 cases and M. clavatus in 3. The patients' median age was 35.5 years. The most common underlying hematological malignancy was acute leukemia. Neutrophil values of 500 cells/mm3 were detected in all patients during Magnusiomyces spp. isolation, with severe neutropenia at less than 100 cells/mm3 in 5. The mean duration of neutropenia prior to Magnusiomyces spp. isolation was 29 days. Breakthrough fungemia developed in 7 patients using echinocandins, fluconazole, and posaconazole. Liposomal amphotericin B and voriconazole were used for initial treatment. The general mortality rate was 37%. All isolates were resistant to echinocandins. Voriconazole possessed the lowest minimum inhibitory concentration value against all isolates. The survival rate was higher among young patients. Mortality was higher among patients followed up in the intensive care unit. Conclusion: Life-threatening Magnusiomyces spp. can spread among patients with long-term neutropenia under treatment for hematological malignancies. Awareness and prompt initiation of treatment can reduce the risk of mortality in invasive infections caused by Magnusiomyces spp.