Question

How do group A streptococci camouflage themselves from white blood cells?

A) they produce coagulase, allowing the bacteria to hide within blood clots.
B) they grow in chains or pairs.
C) they produce streptokinase, which breaks down blood clots.
D) they have hyaluronic acid capsules.
E) they have a coating of protein M.

Answer 1

Group A streptococci camouflage themselves from white blood cells by having a coating of protein M, which inhibits phagocytosis by blocking the binding of complement molecules. The answer is option E.

Step-by-step explanation:

Group A streptococci camouflage themselves from white blood cells by having a coating of protein M. This protein alters the surface of Streptococcus and inhibits phagocytosis by blocking the binding of complement molecules that assist phagocytes in ingesting bacterial pathogens. Protein M helps the bacteria evade the host immune system by interfering with the recognition and phagocytosis (engulfing) by white blood cells.

Additionally, they produce a variety of other virulence factors including streptolysins O and S, hyaluronidase, and streptokinase. However, the coating of protein M is specifically responsible for evading the immune system.