Nocardia araoensis Causing Brain Abscess

Nocardial brain abscess is a rare central nervous system infection with high morbidity and mortality. Most of the human infections, i.e., about 90%, are due to Nocardia asteroides group comprising N. asteroides complex, Nocardia farcinica, and Nocardia nova. Other species rarely cause human infections. Here, we report a case of left parieto-occipital abscess caused by a rare species, Nocardia araoensis, its diagnosis, treatment options, and review of literature. A 73-year-old male, known case of diabetes mellitus, on prolonged oral corticosteroid for autoimmune hemolytic anemia presented with a 1-month history of memory deficit and gait imbalance. On examination, he had a right inferior quadrantanopia and hemiparesis. Magnetic resonance imaging showed a multiloculated ring-enhancing lesion in the left parieto-occipital region. Navigation-assisted biopsy was done. The organism isolated was N. araoensis. He was treated successfully with prolonged course of antibiotics which resulted in complete clinical and radiological resolution. N. araoensis is a rare cause of brain abscess and needs to be suspected in immunocompromised individuals. Early diagnosis and prolonged treatment can result in complete clinical and radiological resolution.