Nocardiosis: death from the ground

Nocardiosis is a rare but potentially life-threatening infection caused by aerobic, filamentous, gram-positive bacteria of the genus Nocardia found in soil and water. Although traditionally found in immunocompromised patients, up to one-third of cases occur in immunocompetent individuals, contributing to frequent diagnostic delays. Historically fatal before the antibiotic era, outcomes have substantially improved with modern antimicrobial therapy and diagnostic advances. However, nocardiosis remains underrecognized due to its nonspecific presentation and ability to mimic more common diseases. Pulmonary involvement is the most common manifestation, often resembling bacterial pneumonia or malignancy and presenting with cough, dyspnea, fever, weight loss, and/or lung masses. Hematogenous dissemination may occur, most commonly affecting the central nervous system, where brain abscesses can mimic neoplastic disease and may initially be asymptomatic. Cutaneous infections following direct inoculation may resemble refractory cellulitis or abscesses. Diagnosis requires a high index of suspicion, prolonged culture incubation, and species-level identification with susceptibility testing. We describe a 70-year-old man with pulmonary nocardiosis complicated by disseminated central nervous system involvement, initially suspected to represent malignancy, who achieved complete clinical and radiographic resolution with prolonged trimethoprim-sulfamethoxazole therapy. This case emphasizes the importance of early consideration of nocardiosis in patients with persistent pulmonary lesions and neurologic symptoms. We aimed to increase clinical awareness of nocardiosis, summarize its diverse presentations, and outline diagnostic and therapeutic principles to improve recognition, management, and outcomes in primary care and specialty settings. Early diagnosis and treatment are essential to reducing morbidity.