Disseminated Nocardia species infection manifested with multiple brain abscesses and lung involvement in an immunocompetent patient: a case report.

Background: Nocardia species are opportunistic pathogens typically transmitted through inhalation or direct skin contact, causing various clinical manifestations, particularly in immunocompromised individuals. Nocardia spp. infection with severe clinical manifestations is rare in immunocompetent patients. In immunocompetent patients, complicated clinical presentations-central nervous system involvement, including multiple large and encapsulated brain abscesses with vasogenic edema and countless miliary-like lesions involving the brain, cerebellum, and brain stem-are rare, and treatment with plain antibiotic therapy to complete remission is highly unlikely compared with the emphasized combined neurosurgical interventions.

Case presentation: We presented the case of a 67-year-old Iranian male with Nocardia spp. infection, an immunocompetent patient with prolonged and insidious manifestation that involved lung and central nervous system with solitary mature and countless miliary-like brain abscesses. Treatment with high-dose parenteral trimethoprim-sulfamethoxazole and meropenem for 6 weeks, followed by oral trimethoprim-sulfamethoxazole, successfully managed the disease without requiring neurosurgical intervention despite clinical indications. A follow-up brain magnetic resonance imaging showed that treatment led to the shrinkage of brain lesions.

Conclusion: We presented a case of Nocardia spp.-infection spp. infection in an immunocompetent patient with no significant history or comorbidities. The patient presented with a central nervous system infection characterized by solitary and miliary-like lesions. This case highlights the importance of considering Nocardia spp. infection as a differential diagnosis, particularly in patients with insidious and complex clinical manifestations. Meanwhile, it seems that more precise neurosurgical indications are necessary.