Mycobacterial disease

Question 1

What are the main characteristics of mycobacteria?

Answer 1

Slender bacillus

Different to all other bacterial genera:
Unusual waxy cell wall:
High lipid content
Slow growing
Different media requirements

Question 2

What are the staining characteristics of mycobacteria?

Answer 2

Poor take up of standard Gram’s stains
(Gram positive: Ghost cells)

Retain certain stains without decolourisation by acid / alcohol:
“acid fast bacilli” (AFBs).
- Ziehl Neelsen (ZN)
- Phenol auramine.