Evaluation of a commercial DNA probe assay for the identification of clinical isolates of Blastomyces dermatitidis from dogs.

A DNA probe assay (AccuProbe, Gen-Probe, Inc., San Diego, CA) for culture confirmation of Blastomyces dermatitidis in clinical isolates was evaluated using 72 isolates of B. dermatitidis (62 dog isolates, five from other animals, four human isolates and one soil isolate). In addition, specificity determinations were performed using 28 American Type Culture Collection (ATCC) fungal isolates, other than B. dermatitidis, representing 21 different genera. The non-isotopic hybrid protection assay, that can be performed in less than 1 h, uses a chemiluminescent acridinium ester DNA probe that is homologous to ribosomal RNA sequences of B. dermatitidis. Positive results were obtained with all 72 B. dermatitidis isolates (100% sensitivity). In addition, no positive results were evidenced with the other 28 non-B. dermatitidis fungal isolates, including six strains of Histoplasma capsulatum (100% specificity).