Bacterial and fungal stains can be used to identify infectious diseases present in the bone marrow, such as mycobacteria or fungal infections including histoplasmosis, cryptococcosis, and coccidioidomycosis.
A Fite stain may be preferred over Ziehl-Neelsen or Kinyoun methods because the Fite stain will pick up atypical Mycobacterium (eg, Mycobacterium avium-intracellulare) in addition to the more typical mycobacterial organisms (eg, Mycobacterium tuberculosis).
Bacterial stains, such as Brown-Hopps, allow some classification of bacteria into gram-positive or gram-negative. However, classification beyond that is difficult microscopically.
In contrast, a more specific diagnosis for fungal organisms is possible using common special stains, such as Grocott's methenamine silver (GMS) and periodic acid-Schiff (PAS). Based on the morphology of the fungus, organisms such as Histoplasma-like organisms, can be distinguished from Candida, Aspergillus, and Mucor.