Nocardia farcinica brain abscess in an immunocompromised patient receiving tofacitinib: a case report

Nocardia farcinica (N. farcinica) brain abscess is a rare but potentially life-threatening opportunistic infection that predominantly occurs in immunocompromised individuals. Patients receiving immunosuppressive therapies may be at increased risk of opportunistic infections; however, the clinical recognition and diagnosis of N.farcinica brain abscess remain challenging. A 55-year-old woman presented with a one-month history of headache and right-sided limb numbness. Brain magnetic resonance imaging (MRI) revealed multiple intracranial space-occupying lesions. Brain biopsy excluded primary or metastatic malignancy and suggested an infectious etiology. The patient had been receiving long-term tofacitinib therapy for two years, with prednisolone and azathioprine discontinued approximately two years before the onset of infection. Next-generation sequencing (NGS) combined with circulating tumor DNA (ctDNA) analysis of brain tissue identified N. farcinica as the causative pathogen. Tofacitinib was discontinued, and the patient was treated with intravenous imipenem-cilastatin (0.5 g every 8 h) and amikacin (0.4 g once daily), combined with oral trimethoprim-sulfamethoxazole (0.48 g every 12 h). After 2.5 months of antimicrobial therapy, the patient showed marked clinical and radiological improvement. Treatment was continued for a total of six months, with no evidence of recurrence during follow-up. This case highlights the importance of considering N. farcinica brain abscess in immunocompromised patients presenting with intracranial lesions. Tissue-based metagenomic sequencing combined with ctDNA analysis may facilitate rapid and accurate identification of N. farcinica , enabling the timely initiation of targeted antimicrobial therapy. Not applicable. This report retrospectively describes the clinical course and management of a patient and did not involve any experimental interventions on a live subject.