Bloodstream Infection Caused by Mycobacterium neoaurum in a Primary Central Nervous System Lymphoma Patient with Toxic Epidermal Necrolysis.

Mycobacterium neoaurum is a rare cause of bacteremia, predominantly affecting immunocompromised hosts with indwelling catheters. A 75-year-old man receiving high-dose methotrexate therapy for primary central nervous system lymphoma without a central venous catheter (CVC) presented with fever. The acid-fast bacilli isolated from his blood cultures were identified as M. neoaurum through 16S rRNA sequencing. Despite broad-spectrum antimicrobial therapy, the patient developed persistent pancytopenia and toxic epidermal necrolysis, which ultimately led to multiple organ failure. M. neoaurum should be considered a potential pathogen in immunocompromised hosts, even in the absence of a CVC. Rapid identification and appropriate antimicrobial selection are essential when mycobacteria are isolated from blood culture.