Nocardia asteroides pneumonia with bacteraemia

TO THE EDITOR: A previously well 57year-old man presented to the emergency department with a 3-day history of severe dyspnoea. Six weeks earlier he had noticed coryzal symptoms with subsequent lethargy, reduced appetite with weight loss, and a non-productive cough. He then developed ankle swelling and increasing abdominal girth. He had a background of excessive alcohol consumption, but had abstained for 10 years. On examination, he was febrile and in respiratory distress, with a respiratory rate of 35 per minute, pulse rate of 130 bpm, and blood pressure of 130/ 85 mmHg. Chest auscultation revealed bilateral diffuse coarse crackles. The chest x-ray is shown in Box 1, and results of additional investigations in Box 2. Despite treatment with broad-spectrum antibiotics (intravenous ceftriaxone, dicloxacillin and erythromycin), the patient’s condition deteriorated rapidly, and he required intubation within 24 hours of presentation. Trap sputa contained abundant thin, partially acidfast, beaded, branching filaments, suggesting Nocardia asteroides, which was later confirmed on culture using conventional biochemical testing. Several blood cultures taken on admission also grew N. asteroides. All cultures for mycobacteria were negative. The patient was treated with intravenous trimethoprim– sulfamethoxazole for a total of 5 weeks and oral minocycline for 14 weeks. He spent 6 weeks in hospital. Liver biopsy, performed because of persistently abnormal hepatic function at follow-up 8 weeks after hospital discharge, showed central fibrosis and noncaseating granulomatous hepatitis (Box 3). The patient received no further treatment and remained well 18 months later, with almost normal hepatic function and a clear chest x-ray. Nocardia bacteraemia is rare, although the incidence appears to be increasing in the immunosuppressed. Nocardia spp. are seldom isolated in blood cultures, with one study finding that blood was the source of only 8% of all Nocardia isolates.1 Up to 30% of patients with Nocardia bacteraemia have coexistent infection with gram-negative bacteria. There has been one previous report of Nocardia pneumonia associated with positive blood cultures and liver disease. However, this patient had documented end-stage chronic liver disease at presentation, was taking prednisolone, and developed nocardiosis after prolonged hospitalisation with gram-negative sepsis.1 Granulomatous reactions are well described in Nocardia infection. Although granulomatous hepatitis is also described in sarcoidosis, it is rare and usually presents with itch and obstructive abnormalities of liver function.4 In our patient, acute N. asteroides infection was the most likely cause of both the pulmonary infiltrate and the granulomatous hepatitis. Not only were results of modified acid-fast stains consistent with Nocardia spp., but cultures from multiple trap sputa and blood specimens also grew N. asteroides, sugLETTERS