Morphological conversion of Blastomyces dermatitidis in tap-water.

Strains of B. dermatitidis not only survived but multiplied in sterile water from 2 separate locations in the USA. Regardless of the growth phase at which the water was inoculated, the resultant growth phase that predominated was temperature-dependent. At 37 degrees C the organism grew primarily as a yeast; at room temperature, growth was mycelial. Complex media may be unnecessary for converting this organism to the yeast phase, and water should be further investigated as a substrate, from both the laboratory and the ecological standpoints.