Gram stain of sputum (x1000) shows inflammatory cells and thin, faintly staining, beaded gram-positive and branching filaments. This Gram stain is consistent with either Nocardia or Actinomyces. Nocardia grew aerobically from this specimen on Sabouraud agar. Nocardia can also be differentiated from Actinomyces with the acid-fast stain.