Histoplasma capsulatum is a dimorphic slow growing fungi. So, the deposition of the fungal colonies at the bottom of the growth medium may be due to the weight of it's massive tuberculate macroconidia and colonial growth pattern of the yeast, since it present it self on Sabouraud's Dextrose agar as a white, fluffy mold that turns to brown to buff with age. However, ensure that you include chloramphenicol and cycloheximide in the growth medium to inhibit bacterial contamination, as some aerobic bacteria can contaminate media to show bottom colonization just as you described.

Hi Osumah Rabiah,

As previously stated, H.capsulatum is a dimorphic fungus, that is, at temperatures above room temperature (> 30-35 ° C) it behaves like yeast, where the reproduction is by budding or endospores. At room temperature (