Failure of sulfonamides and trimethoprim in the treatment of nocardiosis.

An immunocompromised patient with Nocardia brasiliensis pneumonia and empyema acquired disseminated disease due to Nocardia asteroides and died. The treatment of choice for pulmonary or disseminated nocardiosis is 6 to 12 g/day of sulfisoxazole (or adjusted dosage to achieve a serum level of 100 to 150 mg/L) continued for six to 18 months. Combination therapy may be beneficial in selected patients; if trimethoprim therapy is used with sulfonamides, higher than usual doses of trimethoprim may be required to achieve optimal antinocardial activity. When the condition of a patient with nocardiosis falls to improve on sulfonamide therapy, patient compliance should be questioned, serum sulfonamide levels should be measured, cultures and susceptibility studies should be repeated, and a search for sequestered pus should be made.