[Dimorphism in the fungus Coccidioides immitis Rixford et Gilchrist under the action of saprophytic bacilli].

It is shown that there are specific substances produced and secreted into the environment by saprotrophic bacilli. These inhibit the growth of the coccidioidal fungus in its mycelial form and some cells are converted into the yeast form, which leads to the destruction of the fungi (in natural environment) or, if the conditions allow, to their growth in the yeast form. This phenomenon, existence of a large amount of bacilli antagonistic to Coccidioides immitis, may be one of reasons why the latter has not been isolated so far from the soil in the territory of the USSR.