GRAM POSITIVE COCCI; CATALASE POSITIVE

Question 1

Identify:

Identify: (2)

Gram (+) Cocci; Catalase (+)

Answer 1

1. Staphylococci
2. Microccoci

Question 2

What is the positive test for catalase test?

Answer 2

Bubbling/Effervesence

Question 3

Reagent used for catalase test for gram positive cocci:

Answer 3

3% Hydrogen Peroxide (H2O2)

Question 4

Gram positive cocci with tetrad/cuboidal packets morphology:

Answer 4

Micrococci

Question 5

Gram positive cocci with grape-like clusters morphology:

Answer 5

Staphylococci

Question 6

Enumerate significant species in genus Staphylococci: (6)

Answer 6

1. S. aureus
2. S. epidermidis
3. S. saprophyticus
4. S. lugdunensis
5. S. intermedius

Question 7

Species in genus Staphylococci that are coagulase negative: (2)

Answer 7

1. S. epidermidis
2. S. saprophyticus

They are termed as CoNS or Coagulase Negative Staphylococci

Question 8

Coagulase variable Staphylococci: (2)

Answer 8

1. S. lugdunensis
2. S. intermedius

Question 9

Important identification tests for S. aureus: (3)

Answer 9

1. Coagulase test
2. Mannitol Fermentation test
3. DNase test/Thermonuclease test

Question 10

Which type of coagulase does slide method detect?

Answer 10

Bound coagulase/clumping factor

Question 11

Which type of coagulase does tube method detect?

Answer 11

Free coagulase

Question 12

Requirement for tube method in coagulase test:

Answer 12

Incubation at 37degC

Question 13

Reagent for coagulase test:

Answer 13

Rabbit’s plasma collected using EDTA

Question 14

What is the test result if citrated plasma was used in coagulase test?

Answer 14

False positive (+)

Question 15

Positive result for coagulase test:

Answer 15

Clot formation

Question 16

What does Mannitol Fermentation test detect?

Answer 16

Acid production

Question 17

Reagent and media for Mannitol Fermentation test: (3)

Answer 17

1. Mannitol Salt agar
2. 7.5% Salt
3. Phenol red

Question 18

What is the inhibitor of Mannitol Fermentation test:

Answer 18

7.5% salt

Question 19

What is the indicator of Mannitol Fermentation test:

Answer 19

Phenol red

Question 20

Positive result for Mannitol Fermentation Test:

Answer 20

Yellow halo around the colonies

Question 21

This is the only species that grows in MSA:

Answer 21

S. aureus