True about Bacterial capsule is following except:
|B||Stains by gram stain|
|C||Protects bacteria from lytic enzymes|
|D||Lost by repeated subcultures|
a. Capsule has no net charge and hence can not be gram stained.
b. Capsule can be demonstrated by negative staining and Quellung reaction.
c. It is an important virulence factor that protects the bacterium from phagocytosis, lytic enzymes and phages.
d. Most capsules of bacteria are polysaccharide in nature. Bacillus anthracis has a polypeptide capsule.
e. Repeated subculture can lead to loss of capsule leading to a change in colony morphology from smooth to rough.
f. Eg. Of capsulated bacteria: S.pneumoniae, K.pneumoniae, H.influenzae, N.meningitidis, Cl.perfringens, B.anthracis, Bacteroides fragilis, Y.pestis.