Nocardia cyriacigeorgica Identified by Bronchial Washing During Evaluation of Radiologic Progression in a Patient With Prior Nontuberculous Mycobacterial Diseases

Pulmonary nocardiosis may occur in immunocompetent patients with structural lung disease and may resemble the progression of nontuberculous mycobacterial pulmonary disease. We report an 81‐year‐old immunocompetent woman with chronic bronchiectasis and prior Mycobacterium kansasii , M. intracellulare , and M. abscessus infections. Despite persistently negative sputum mycobacterial cultures, chest computed tomography (CT) revealed progressive nodular bronchiectatic changes. Bronchial washing from the right B5 bronchus yielded Nocardia cyriacigeorgica ; mycobacterial studies were negative. Trimethoprim–sulfamethoxazole was stopped shortly after initiation because of drug eruption, and minocycline monotherapy led to transient symptomatic and radiologic improvement. However, follow‐up CT at 6 months revealed radiologic progression. Repeat bronchoscopy was culture‐negative, but bronchial washing cytology revealed filamentous organisms suggestive of persistent nocardial infection. Minocycline monotherapy was continued for 12 months. Chest CT at 12 months revealed new contralateral left upper lobe bronchocentric abnormalities. This case highlights the importance of bronchial washing and longitudinal reassessment when radiologic progression remains unexplained by sputum evaluation.