ch 3 streptococci a

Question 1

Streptococcus pneumoniae is

Answer 1

the leading cause of pneumonia. It is a normal inhabitant of the human upper respiratory tract

Question 2

Viridans Streptococci are

Answer 2

normal flora in the mouth and the upper respiratory tract

Question 3

Streptococcus Viridans gram stain

Answer 3

Gram positive, cocci, short chain

Question 4

Streptococci pneumoniae (Pneumococci) gram stain

Answer 4

Gram positive, diplococci

Question 5

Streptococci pneumoniae media and colony

Answer 5

Blood agar
α-hemolysis

Question 6

Viridans Streptococci media and colony

Answer 6

Blood agar
α-hemolysis

Question 7

Susceptibility to optochin disc

Answer 7

Streptococcus Viridans Streptococci (R)
pneumoniae (Pneumococci) (S)

Question 8

Bile solubility test

Answer 8

Streptococcus Viridans Streptococci : Insoluble in bile

pneumoniae (Pneumococci) : Soluble in bile

Question 9

Capsule

Answer 9

Streptococcus Viridans Streptococci : No capsule (except Streptococcus mutans)

pneumoniae (Pneumococci) : Has capsule

Question 10

Inulin fermentation test

Answer 10

Streptococcus Viridans Streptococci : Negative (don’t ferment inulin)

pneumoniae (Pneumococci) : Positive (ferment inulin)

Question 11

This test is useful to differentiate Pneumococci from Streptococci as the latter do not ferment Inulin sugar while Pneumococci do ferment it.

Answer 11

Inulin Test

Question 12

Virulence Factors of S. pneumoniae:

Answer 12

Polysaccharide Capsule
• Pili
Pneumolysin

Question 13

Diseases caused by S. pneumoniae:

Answer 13

Lobar pneumonia • Bacteremia • • Otitis

Question 14

Diseases caused by Viridans Streptococci:

Answer 14

Dental infections, including dental caries, abscesses • Subacute endocarditis