Invasive fungal infection caused by Blastobotrys mokoenaii in an immunocompromised patient with acute myeloid leukemia: A case report.

Blastobotrys is a genus of rare yeast that is increasingly recognized as a cause of fungal infections in humans. However, there have been no reports of fungal infections in humans caused by Blastobotrys mokoenaii. We describe a case of invasive fungal infection (IFI) caused by B. mokoenaii in an immunocompromised patient with acute myeloid leukemia (AML). A 46-year-old man with relapsed/refractory AML underwent a second allogeneic peripheral blood hematopoietic stem cell transplantation (allo-PBSCT) during remission. The patient had prolonged neutropenia and received systemic steroid therapy for graft-versus-host disease before the second allo-PBSCT. Uncommon yeast was isolated from the blood cultures obtained on day 4. We initially suspected that the uncommon yeast was Trichosporon spp. based on its morphology. However, unlike Trichosporon spp., in vitro antifungal susceptibility tests showed that this yeast isolate was resistant to micafungin, caspofungin, voriconazole, itraconazole, and fluconazole. We performed DNA sequencing and identified it as B. mokoenaii. B. mokoenaii was persistently isolated from blood cultures taken during combination therapy with liposomal amphotericin B and voriconazole. The patient died of multiorgan failure on day 24. B. mokoenaii can cause severe IFI in immunocompromised patients; however, it may not be correctly identified by routine clinical microbiology testing in a hospital laboratory and DNA sequencing is useful for diagnosis.
Competing Interests: Declaration of competing interest T.T. reports lecture fees from Sanofi and research funding from Pfizer and AbbVie. M. Nishimoto reports research funding from Astellas. Y.N. reports research funding from Astellas and AbbVie. K.K. reports lecture fees from MSD, Pfizer, Shionogi & Co., Ltd., Sumitomo Pharma Co., Ltd., and Asahi Kasei Pharma Corporation. M.H. reports grant from Chugai Pharmaceutical and research funding from Nippon Shinyaku. The other authors declare no conflicts of interest associated with this manuscript.
(Copyright © 2023 Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Infection Prevention and Control. Published by Elsevier Ltd. All rights reserved.)