TESTS FOR IDENTIFICATION OF BETA-HEMOLYTIC STREPTOCOCCI

Question 1

Identify group A and group B Beta-hemolytic streptococci:

Answer 1

Bacitracin-SXT Susceptibility test

Question 2

Group A strep

Bacitracin:
SXT:

Answer 2

Group A strep

Bacitracin: Susceptible
SXT: Resistant

mnemonic: “B-BRAS”

B - Bacitracin
B - group B is
R - Resistant
A - group A is
S - Susceptible

Question 3

Group B strep

Bacitracin:
SXT:

Answer 3

Group B strep

Bacitracin: Resistant
SXT: Resistant

mnemonic: “B-BRAS”

B - Bacitracin
B - group B is
R - Resistant
A - group A is
S - Susceptible

Question 4

Differentiate Enterococcus species (+) from non-enterococcus species (-)

Answer 4

PYRase (PYR test)

Question 5

Positive result in PYR test:

Answer 5

Pink to cherry red color after the addition of the color developer

Question 6

Group A strep is also PYR-positive

true or false

Answer 6

True

Group A strep is also PYR-positive

Question 7

Test used to identify group B streptococcus

Answer 7

CAMP test

Question 8

In CAMP test, a characteristic “_______” hemolytic pattern results when the S. agalactiae is streaked perpendicularly to beta-hemolytic S. aureus

Answer 8

“arrow-head” enhanced hemolytic pattern: S, agalactiae

Question 9

CAMP (+) organism’ “shovel” hemolytic pattern

Answer 9

Listeria monocytogenes

Question 10

Reverse CAMP (+) organism:

Answer 10

C. perfringens

Question 11

Alternative to CAMP; identify group B streptococcus

Answer 11

Hippurate Hydrolysis

Question 12

Hippurate Hydrolysis positive result:

Answer 12

Purple color after adding ninhydrin reagent