A Reference Laboratory Surveillance on Fungal Isolates from Patients with Haematological Malignancy in Japan

Invasive fungal disease (IFD) in patients with haematological disorders is a fatal disease, making rapid identification and treatment crucial. However, the identification of the causative fungus is often difficult, sometimes even impossible. There have been few reports concerning the causative species of IFD. This study aimed to investigate the epidemiology and causative organism of IFD in patients with haematological diseases in Japan. We analyzed the IFD cases among the patients with haematological malignancies identified at the Medical Mycological Research Center, Chiba University, between 2013 and 2019. The most common underlying disease was acute myeloid leukaemia (34.3%). Forty-six point one percent of IFD patients received haematopoietic stem cell transplantation (HSCT). The major pathogens were Aspergillus, Candida, and Fusarium. Aspergillus fumigatus was the most common Aspergillus species, and Candida fermentati and Fusarium petroliphilum were the most common Candida and Fusarium species, respectively, in this analysis. Furthermore, various cryptic species and non-albicans Candida were identified. The drug susceptibility of such relatively rare strains suggests that analysis of the causative fungi should provide valuable information for therapeutic options. Therefore, our study indicated that it is clinically significant to identify the organism in as much detail as possible.