F, Lab(biochemtest Gram+ Cocci)

Question 1

used to differentiate Staphylococcus
aureus (positive) from coagulase-negative
staphylococci (negative).

Answer 1

Coagulase test

Question 2

Bound also known as

Answer 2

Clumping factor

Question 2

S. aureus produces two forms of coagulase

Answer 2

bound
and free

Question 3

The clotting mechanism involves activation of a
plasma

Answer 3

coagulase-reacting factor (CRF)

Question 4

Positive for slide coagulase test

Answer 4

Macroscopic clumping in 10 sec

Question 5

Tube coagulase test

Answer 5

Emulsify several colonies of the unknown clinical
isolate in

Question 6

0.5 mL of rabbit plasma (with EDTA)

Answer 6

Tube coagulase test is incubated at

Question 7

Tube coagulase test Emulsify several colonies of the unknown clinical
isolate in

Answer 7

0.5 mL of rabbit plasma

Question 8

Coagulase tube test Incubate tube at

Answer 8

35°C-37°C in ambient air for 1-4
hours.

Question 9

Positive for TUBE COAGULASE TEST

Answer 9

Clot of any size

Question 10

This test is used to differentiate organisms based on
the production of deoxyribonuclease. It is used to
distinguish S. aureus (positive) from other species.

Answer 10

DNAse TEST AGAR

Question 10

DNAse TEST AGAR used to differentiate organisms based on
the production of

Answer 10

deoxyribonuclease

Question 11

test is used to determine the ability of an
organism to hydrolyze DNA.

Answer 11

DNAse TEST AGAR

Question 12

Color of medium form DNAse TEST AGAR

Answer 12

Pale green

Question 13

Color of medium form DNAse TEST AGAR

Answer 13

Pale green

Question 14

DNAse TEST AGAR The medium is pale green because of the

Answer 14

DNA-
methyl green complex.

Question 15

DNAse TEST AGAR must be incubated

Answer 15

aerobically at 35°C-37°C for 13-24 hrs

Question 16

Positive for DNAse TEST AGAR

Answer 16

medium colorless around the test
organism.

Question 17

Negative for DNAse TEST AGAR

Answer 17

medium stays green

Question 18

used to differentiate Gram-positive,
catalase-positive cocci (Micrococci from
Staphylococci).

Answer 18

MICRODASE TEST - Modified Oxidase Test

Question 19

The Microdase test is a rapid method to differentiate
Staphylococcus from Micrococcus spp. by
detection of the enzyme oxidase, In the presence of
atmospheric oxygen, the oxidase enzyme reacts
with the oxidase reagent and cytochrome C to form
the colored compound

Answer 19

Indophenol

Question 20

For modified oxidase test rub a small
amount of several colonies of an

Answer 20

18-24 hr pure
culture grown on BAP

Question 21

Modified oxidase test positive

Answer 21

Dev’t of blue to purple color

Question 22

This test differentiates catalase-positive
micrococcal & staphylococcal species from
catalase-negative streptococcal species

Answer 22

CATALASE TEST

Question 23

Aerobic & facultative anaerobic organisms produce

Answer 23

H202 and superoxide radical (O2-)

Question 24

Catalase test positive

Answer 24

Copious bubbling

Question 25

This test is used for the presumptive identification of enterococci and organisms in the Streptococcus bovis group. The test differentiates enterococci and group D streptococci from non- group D viridans streptococci.

Answer 25

BILE SOLUBILITY TEST

Question 26

BILE SOLUBILITY TEST positive

Answer 26

Growth and blackening of the agar slant

Question 27

BILE SOLUBILITY TEST negative

Answer 27

Growth and no blackening of the medium

Question 28

Other term for NEUFELD QUELLUNG TEST

Answer 28

precipitin test"

Question 29

This microscopic "precipitin test" can be used to identify pneumococci or to determine the capsular serotype of individual pneumococcal isolates. (S. pneumoniae, N. meningitidis, H. influenzae, K. pneumoniae)

Answer 29

NEUFELD QUELLUNG TEST

Question 30

capsule so that it appears "swollen" and more visible.

Answer 30

NEUFELD QUELLUNG TEST

Question 31

NEUFELD QUELLUNG TEST positive

Answer 31

capsule appears as a sharply demarcated halo around the dark blue stained cell

Question 32

NEUFELD QUELLUNG TEST negative

Answer 32

no appearance of a clear, enlarged halo surrounding the stained cell

Question 33

This test is used to determine the effect of optochin on an organism.

Answer 33

OPTOCHIN SUSCEPTIBILITY TEST

Question 34

OPTOCHIN SUSCEPTIBILITY TEST positive

Answer 34

Zone of inhibition at least 14 mm in diameter with 6-mm disk

Question 35

OPTOCHIN SUSCEPTIBILITY TEST negative

Answer 35

No zone of inhibition

Question 37

This test is used for presumptive identification & differentiation of B-hemolytic group A streptococci (S. pyogenes-susceptible) from other B-hemolytic group A streptococci. It is also used to distinguish staphylococci species (resistant) from micrococci (susceptible).

Answer 37

BACITRACIN SUSCEPTIBILITY TEST

Question 38

BACITRACIN SUSCEPTIBILITY TEST positive

Answer 38

Any zone of inhibition greater than 10 mm; susceptible

Question 39

used to differentiate group B streptococci (Streptococcus agalactide-positive) from other streptococcal species.

Answer 39

Christie, Atkins, and Munch-Peterson (CAMP) test

Question 40

BACITRACIN SUSCEPTIBILITY TEST negative

Answer 40

No zone of inhibition

Question 41

also produces a positive CAMP reaction.

Answer 41

Listeria monocytogenes

Question 42

Camp positive

Answer 42

Enhanced hemolysis is indicated by an arrowhead-shaped zone of beta-hemolysis at the juncture of the two organisms.

Question 43

Camp negative

Answer 43

No enhancement of hemolysis