Disseminated nocardiosis with Nocardia brasiliensis bacteremia in a patient with rheumatoid arthritis using tocilizumab.

Here, we present a case of disseminated nocardiosis, involving pneumonia, percutaneous abscess, and bacteremia, in a 67-year-old Japanese woman. She had also been treated for rheumatoid arthritis with prednisolone, methotrexate, and tocilizumab (interleukin-6 receptor inhibitor). Based on the 16S rRNA sequence analysis and a blast search, we identified the isolate as Nocardia brasiliensis. We discontinued methotrexate and tocilizumab on admission, and administered intravenous antimicrobial combination therapy for 6 weeks, followed by oral trimethoprim-sulfamethoxazole for 12 months, in total. Nocardia bacteremia is rare, often difficult to diagnose, and substantially fatal. However, due to our prompt diagnosis within one day of the onset of symptoms, and administration of appropriate treatment based on antimicrobial susceptibilities, this patient succeeded in surviving the infection. Not only microbiologists but also clinicians should be aware of the characteristic bacterial form of Gram/Kinyoun staining for early recognition of nocardiosis.