Question

Why are encapsulated strains of Streptococcus pneumoniae more likely to cause disease than strains that do not produce a capsule?

A) They are better at evading the host immune system.
B) They are more susceptible to antibiotics.
C) They produce toxins that are harmful to the host.
D) They have a lower growth rate in the host environment.

Answer 1

Encapsulated strains of Streptococcus pneumoniae are more virulent due to their capability to evade the host's immune system using their protective capsule which prevents phagocytosis, making them more likely to cause disease.

Step-by-step explanation:

Encapsulated strains of Streptococcus pneumoniae are more likely to cause disease because A) They are better at evading the host immune system. The capsule prevents immune cells from being able to adhere and then phagocytose the cell. This evasion of the immune system allows encapsulated strains of Streptococcus pneumoniae to be more likely to cause disease than strains that do not produce a capsule.The capsule acts as a defensive barrier, protecting the bacteria from being phagocytosed by white blood cells.

This virulence factor contributes to the microorganism's pathogenicity through immune evasion by preventing the immune cells from adhering and phagocytosing the cell. Furthermore, it increases the size of the bacterial cell, making it more difficult for phagocytes to engulf it. Not only do capsules help the bacteria adhere to host tissues, but they also inhibit the recognition and destruction by the host's immune system. In contrast, nonencapsulated strains lack this protective layer, making them less virulent and more susceptible to phagocytosis.