A Case of Pulmonary Infection with Nocardia Caviae

Abstract

Nocardia species are Gram positive, partially acid fast, branching actinomycetes which infreguently cause illness in man. But in an immune-supressed host, it can cause opportunistic pulmonary infection first and later dissemination. There are nine species of Nocardia. Common pathogens are N. asteroides and N. brasiliensis which account for 85-95 % of all nocardiosis. Infections by other Nocardia species are rarely reported and N. caviae accounts for only 0.5~3% of all nocardiosis. Here we present a case of pulmonary infection with Nocardia caviae in a patient on chronic steroid therapy. The patient was a 69-year-old male with pulmonary tuberculosis 10 years ago. He habitually had taken over-the-counter steroids due to degenerative arthritis of knees. This time, he visited the hospital with fever, cough, sputum, general weakness and dyspnea of about 20-days duration. He was Cushingoid in appearance, and chest auscultation revealed crackles on both lungs. Radiologic examination showed multiple nodular opacities on the right lung. But, non-invasive studies were inconclusive. Percutaneous needle aspiration was performed for the lung lesion and Nocardia species were found on Gram stain and modified acid fast stain. Culture and biochemical study of aspirated materials concluded that N. caviae was the causative organism. Treatment was successful with ampicillin-sulbactam and trimethoprim-sulfamethoxazole.