A fatal case of pneumonia caused by Thermothelomyces thermophila

Thermothelomyces thermophila (formerly Myceliophthora thermophila) is usually found in soil and specifically compost as an environmental dematiaceous fungus. Here, we report the first case of invasive pulmonary infection caused by T. thermophila in a pediatric patient with acute lymphoblastic leukemia. T. thermophila was serially cultured from bronchoalveolar lavage (BAL) fluid and sputum samples obtained from this patient with respiratory symptoms. The patient received antifungal treatment with liposomal amphotericin B (160 mg daily) and itraconazole (200 mg daily) combination therapy, but she died. By the antifungal susceptibility testing, low minimum inhibitory concentrations (MIC) were observed for itraconazole (MIC 0.06 μg/mL), voriconazole (MIC 0.12 μg/mL), and posaconazole (MIC 0.03 μg/mL) but high MIC was observed with amphotericin B (MIC 4.0 μg/mL). Since T. thermophila is usually found in the environment, it can be considered as a contaminant and may cause difficulties in diagnosis. Therefore, it is necessary to confirm the potential of pathogen through repeated culture and to conduct an antifungal susceptibility testing to find a suitable antifungal agent.