Gram Positive Cocci
Which of the following is the primary virulence factor of Streptococcus pneumoniae?
a. Bile solubility and optochin sensitivity are presumptive identification tests that identify Streptococcus pneumoniae from other alpha-hemolytic Streptococci.
b. The polysaccharide capsule occurs in dozens of antigenic types, but types 1-8 are responsible for about 75 percent of the cases of pneumococcal pneumonia.
c. Vaccines are available that give approximately 90 percent protection and usually contain 23 types of carbohydrates for the U.S.-licensed preparation.