Unusual Presentation of Nocardiosis With Pleural Effusion in an Immunocompetent Host

Nocardiosis is a disease caused by gram-positive, catalase-positive, rod-shaped bacteria that stain weakly on a Gram stain. It usually affects the lungs and skin but can cause disseminated infections. Nocardia has 85 species, ranging from nonpathogenic to pathogenic. Nocardia is an opportunistic organism that causes infections in the immunocompromised; however, 7% of the immunocompetent population has suffered from Nocardia infection. This case report highlights an unusual occurrence of pulmonary nocardiosis in a 31-year-old woman with a normal immune system. She was initially treated as an outpatient for what appeared to be community-acquired pneumonia. However, her condition deteriorated, ultimately revealing a substantial right pleural effusion with loculation and adjacent compressive atelectasis affecting a significant portion of her right middle and lower lung lobes, as detected by a CT scan followed by pleural fluid analysis which confirmed the infection. By sharing this experience, we aim to contribute to the collective knowledge of medical professionals and improve the accuracy of diagnosis and treatment.