Background: Aureobasidium melanigenum is a ubiquitous dematiaceous fungus that rarely causes invasive human infections. Here, we present a case of Aureobasidium melanigenum bloodstream infection in a 20-year-old man with long-term catheter use.

Case presentation: A 20-year-old man receiving home care with severe disabilities due to cerebral palsy and short bowel syndrome, resulting in long-term central venous catheter use, was referred to our hospital with a fever. After the detection of yeast-like cells in blood cultures on day 3, antifungal therapy was initiated. Two identification tests performed at a clinical microbiological laboratory showed different identification results: Aureobasidium pullulans from matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and Cryptococcus albidus from a VITEK2 system. Therefore, we changed the antifungal drug to liposomal amphotericin B. The fungus was identified as A. melanigenum by DNA sequence-based analysis. The patient recovered with antifungal therapy and long-term catheter removal.

Conclusion: It is difficult to correctly identify A. melanigenum by routine microbiological testing. Clinicians must pay attention to the process of identification of yeast-like cells and retain A. melanigenum in cases of refractory fungal infection.

Yamamoto S, Ikeda M, Ohama Y, Sunouchi T, Hoshino Y, Ito H, Yamashita M, Kanno Y, Okamoto K, Yamagoe S, Miyazaki Y, Okugawa S, Fujishiro J, Moriya K. Aureobasidium melanigenum catheter-related bloodstream infection: a case report. BMC Infect Dis. 2022 Apr 5;22(1):335. doi: 10.1186/s12879-022-07310-9. PMID: 35382751; PMCID: PMC8981616.