Streptococcus pneumoniae has which virulence factors?

Streptococcus pneumoniae has which virulence factors?

• A. Teichoic acids
• B. Hyaluronidase
• C. Polysaccharide capsule, IgA protease
• D. Capsule with IgA protease only

Answer: (C)

Pneumococcus relies on two main virulence tools: a polysaccharide capsule that prevents phagocytosis, and an IgA protease that cleaves secretory IgA at mucosal surfaces to help colonization. The capsule is the primary factor that allows it to resist clearance and cause invasive disease, while IgA protease enables it to establish infection in the respiratory tract. Teichoic acids are structural components common to many Gram-positive bacteria and aren’t the defining virulence factors for this organism. Hyaluronidase is more characteristic of other streptococci that spread through tissues. So, capsule and IgA protease together best explain the virulence of Streptococcus pneumoniae.

Pneumococcus relies on two main virulence tools: a polysaccharide capsule that prevents phagocytosis, and an IgA protease that cleaves secretory IgA at mucosal surfaces to help colonization. The capsule is the primary factor that allows it to resist clearance and cause invasive disease, while IgA protease enables it to establish infection in the respiratory tract. Teichoic acids are structural components common to many Gram-positive bacteria and aren’t the defining virulence factors for this organism. Hyaluronidase is more characteristic of other streptococci that spread through tissues. So, capsule and IgA protease together best explain the virulence of Streptococcus pneumoniae.