Western blot monitoring of disseminated Nocardia nova infection treated with clarithromycin, imipenem, and surgical drainage.

A case of disseminated infection due to Nocardia nova with subcutaneous popliteal and retrosternal abscesses and lung involvement in an immunocompromised patient is reported. The patient did not respond to sulfonamide therapy. Clinical recovery was obtained upon treatment with imipenem then clarithromycin. Western blot studies revealed an antibody response to a known Nocardia-specific 55-kDa antigen in four successive sera samples collected in the period from the time of admission to seven months later. The resolution of the disseminated nocardiosis and efficacy of the clarithromycin treatment were assessed on the basis of disappearance of the antibodies to the 55-kDa antigen, without invasive sampling.