Acid-fast bacteria

Gram staining is a method of staining bacteria to add colouration and facilitate visualisation under a microscope.

Acid-fast bacteria are resistant to staining and then resistant to discolouration. They must be identified with a Ziehl–Neelsen stain.

Known Acid-fast species

Family : Mycobacteriaceae

• Mycobacterium leprae : Leprosy (Hansen's disease)
• Mycobacterium lepromatosis : Leprosy (Hansen's disease) 
• Mycobacterium tuberculosis : Tuberculosis 
• Mycobacterium ulcerans infection : Buruli ulcer 

Family : Nocardiaceae

• Nocardia asteroides : Nocardiosis 
• Nocardia brasiliensis : Nocardiosis