Caser Report: A Rare Case of Pulmonary Nocardiosis Caused by Nocardia pseudobrasiliensis After Liver Transplantation

Nocardia is a gram-positive bacillus with the microscopic appearance of branching hyphae and is mainly distributed in the soil. Nocardiosis more frequently occurs in immunosuppressed patients. Since nocardiosis has a high mortality rate, immediate diagnosis and treatment are needed. We report the first case of pulmonary nocardiosis caused by Nocardia pseudobrasiliensis after liver transplantation. A 58-year-old woman underwent living-donor transplantation for primary biliary cholangitis. Seven months after transplantation, she came to our hospital complaining of fever and anorexia. Computed tomography of the lungs showed a 45 mm large nodule affecting the upper lobe of the left lung. We started administering empiric antibiotics and tapering immunosuppression, but the patient's condition gradually worsened, and lung lesions increased. On the fifth day after hospitalization, bacteria developed from sputum cultures were identified as N. pseudobrasiliensis by matrix-assisted laser desorption ionization time of flight mass spectrometry. We started treatment with trimethoprim-sulfamethoxazole. The patient's clinical symptoms and laboratory data improved quickly. After one month of hospitalization, this patient was discharged. Then, the lung lesion almost vanished. Ten years after her transplant, the patient is alive with a well-functioning graft.