T22: Mycobacteria

characteristic feature in mycobacteria cell wall

mycolic acid

m.tuberculosis complex & M.leprae - mode of transmission

airborne particles from human to human

m.tuberculosis - replication

incapable of replication in inanimate environment

mask used to prevent MTB transmission

N95 mask

why have to use N95

has more filters for filtering airborne droplets, can filter small particles size 0.3micrometres w/ 95% efficacy

which biosafety lvl for MTB culture

biosafety lvl 3

acid-fast stain types for MTB

1. kinyoun stain (cold AFB stain)

2. ziehl-neelsen (hot AFB stain)

3. fluorochrome auramine O/rhodamine 8

Nocardia - characteristics

weakly acid-fast, produce aerial mycelia

Nocardia - colony

powdery, chalk, matte, velvet, wrinkled

Nocardia - pathogenic species

• N. brasiliensis: skin

• N. farcinica: multidrug resistance

nocardiosis - symptoms

productive cough → disseminated to CNS

Nocardia - diagnosis

modified AFB stain