Use of the Exoantigen Test to Identify Blastomyces dermatitidis, Coccidioides immitis, and Histoplasma capsulatum in Mixed Cultures

Cultures of Blastomyces dermatitidis, Coccidioides immitis, and Histoplasma capsulatum were inoculated with each of five saprophytes to simulate contaminated cultures. The cultures were extracted and tested in the immunodiffusion exoantigen test. Twenty-nine of 30 cultures were correctly identified. The saprophytes did not appear to interfere with the exoantigen test.