Gram Positive Cocci
True about streptococcus (AIIMS May 2010)
|A||Pyrogenic toxin is plasmid mediated|
|B||Streptodornase depolymerizes DNA|
|C||Streptokinase O is inactive in reduced state|
|D||Hyaluronidase is not antigenic|
a. Streptodornase depolymerises DNA- Deoxyribonucleases produced by Streptococcus are called streptodornase.
b. This enzyme helps to liquefy the thick pus of pyogenic exudates and may be responsible for the thin serous character of streptococcal exudates.
c. A preparation of streptodornase and streptokinase is available for this application of this ability in liquefying localised collections of thick exudates such as empyema.
d. 4 antigenically distinct DNAases have been recognised, of which type B is most antigenic. Demonstration of anti-DNAase B has been used for retrospective diagnosis of S. pyogenes infection, especially skin infections, where ASO titers may be low.
e. Streptodornase B and D also possess ribonuclease activity.