I think the subject of Fite's acid fast stain has been reviewed at considerable length on Histonet before.

This modification of the standard light microscopic acid fast stain has been used to stain Mycobacterium leprae (the etiologic agent of leprosy/Hansen's disease), which has somewhat different staining characteristics from Mycobacterium tuberculosis and I suppose - though this question has never to my knowledge been adequately addressed - other mycobacteria of clinical significance.

All of these light microscopic techniques were rendered obsolete by fluorescence microscopy (fluorescent acid fast staining) many years ago, though they persist as hallowed rituals among elderly pathologists, many of whom alas are now twenty years younger than I am.

Bob Richmond
Samurai Pa