Recovery of Histoplasma capsulatum from BACTEC TB media

From 1990 through 1994, we fortuitously isolated Histoplasma capsulatum from six patients with AIDS whose specimens of blood were processed by the BACTEC system using Middlebrook broth selective for acid-fast bacilli (13A medium). Growth indices became positive after an average of 17 days of incubation (range, 11 to 20 days). No acid-fast bacilli were seen, but small budding yeasts characteristic of H. capsulatum were present.