Mycobacteria can convert BODIPY-cholesterol and similar NBD-labeled steroids. 4-En-3-one derivatives are major fluorescent products of the bioconversion. NBD fluorophore of the compounds undergoes degradation in the mycobacteria. The steroids cause staining of envelope lipids and intracellular lipid droplets. 3-NBD-cholestane don’t converted by M. tuberculosis H37Rv and M. smegmatis mc2 155.