Gram Positive Cocci
Virulence of Pneumococci is due to:
|D||All of the above|
The most important antigen of the pneumococcus is the type specific capsular polysaccharide. As this polysaccharide diffuses into the culture medium or infective exudates and tissue, it is also called the ‘specific soluble substance (SSS)’. Pneumococci are classified into more than 85 capsular types based on the antigenic nature of the capsular polysaccharide
a. The virulence of the pneumocci depends on its capsule and the production of a toxin called pneumolysin. The Capsular Polysaccharide because of its acidic and hydrophilic properties protects the cocci from phagocytosis.
b. Capsulated pneumococci are not effectively phagocytosed efficiently in fluid media or exudates. They are, however, susceptible to ‘surface phagocytosis’, being engulfed against a firm surface, such as fibrin clot or epithelium
c. Nucleoprotein is an antigen situated deep inside the cell and is species specific
d. Somatic ‘C’ Carbohydrate antigen is species specific