IN-VITRO INTERACTIONS BETWEEN HISTOPLASMA-CAPSULATUM VAR. DUBOISI ANDOTHER FUNGI

Histoplasma capsulatum var. duboisii has only recently been shown to o ccur naturally in soil admired with bat guano in a bat cave. We report our observations on the in vitro interaction of Histoplasma capsulatu m var. duboisii with other fungi recovered from the same habitat or ot her sources by employing co-culture technique and by investigating ant ibiosis between H. capsulatum var. duboisii and other fungi. The range of interactions varied from total overgrowth of Histoplasma by Asperg illus fumigatus and Microsporum gypseum, through partial antagonism by Lecythophora mutabilis, to mutual inhibition by Wangiella dermatitidi s. Those fungi that exhibited a competitive advantage in terms of grow th did not affect the viability of Histoplasma. Lysis and mycoparasiti c structures were not observed in the co-cultures. However, the cultur al filtrate of Chrysosporium indicum inhibited the growth of the Histo plasma strains. The results suggest the ability of H. capsulatum var. duboisii to co-exist with a variety of other potentially pathogenic an d nonpathogenic fungi in an ecological niche.