BACTE LAB LA12

Question 1

used to detect the presence of the catalase enzyme which breaks down hydrogen peroxide into water and oxygen

Answer 1

CATALASE TEST

Question 2

use to differentiate staphylococci from streptococci

Answer 2

CATALASE TEST

Question 3

Positive Result for CATALASE TEST

Answer 3

Presence of Bubbling

Question 4

A small amount of bacterial culture is placed on a microscope slide, and a drop of 3% H2O2 is added

Answer 4

SLIDE (DROP) METHOD Catalase Test

Question 5

A Bacterial sample is placed in a test tube containing 3% H2O2

Answer 5

TUBE METHOD Catalase test

Question 6

A heavily inoculated agar slant is flooded with 3% H2O2, and bubble formation is observed against a dark background

Answer 6

TUBE (SLANT) METHOD Catalase Test

Question 7

Test that differentiates Staphylococcus aureus from other Staphylococcus species

Answer 7

Coagulase Test

Question 8

A suspension of bacteria in EDTA-treated rabbit plasma is examined for clumping, which indicates the presence of bound coagulase

Answer 8

Slide Coagulase Test

Question 9

Bacteria are mixed in rabbit plasma and incubated. Clot formation within 24 hours indicates positive result. Used to free coagulase

Answer 9

Tube Coagulase Test

Question 10

Organism that may show coagulase positive

Answer 10

S. aureus

Question 11

selective and differential for Staphylococcus species. Containing 7.5% NaCl, which inhibits most non-staphylococcal bacteria, and mannitol a fermentable sugar

Answer 11

Mannitol Salt Agar Test

Question 12

pH indicator for Mannitol Salt Agar Test

Answer 12

Phenol red

Question 13

a supplemental test for S. aureus

Answer 13

DNAse test

Question 14

result: Mannitol fermentation with yellow colonies

Answer 14

Suggestive of S. aureus which ferments mannitol

Question 15

result: growth with pink/ red colonies

Answer 15

Suggestive of other staphylococcal species, which do not ferment mannitol

Question 16

this test differentiates coagulase-negative staphylococci based on their susceptibility to the antibiotic novobiocin

Answer 16

Novobiocin Susceptibility Test

Question 17

Plate used for Novobiocin Susceptibility Test

Answer 17

Mueller-Hinton agar plate, BAP

Question 18

The amount of time for the culture with Novobiocin disk is incubated before ZOI is measured

Answer 18

18-24 hours

Question 19

Novobiocin ZOI of greater than 16mm

Answer 19

Susceptible (S. epidermidis, S. lugdunensis)

Question 20

Novobiocin ZOI of lesser than or equal to 16mm

Answer 20

Resistant (S. saprophyticus)

Question 21

This test differentiates B-hemolytic Group A strep from other B-hemolytic strep based on susceptibility to bacitracin

Answer 21

Bacitracin susceptibility test

Question 22

Plate used for Bacitracin susceptibility test

Answer 22

BAP

Question 23

_____ units of bacitracin disk is placed on the heaviest growth areas and incubated at _______ for _______

Answer 23

0.04 units

35-37 deg C

18-24 hours

Question 24

Bacitracin ZOI of greater than 10mm

Answer 24

Susceptible (S. pyogenes)

Question 25

Bacitracin no ZOI present

Answer 25

Other B-hemolytic streptococci

Question 26

used for differentiating Streptococcal based groups based on their resistance or susceptibility to trimethoprim-sulfamethoxazole

Answer 26

SXT Susceptibility Test

Question 27

Resistant to SXT but susceptible to bacitracin

Answer 27

Group A Strep

Question 28

Resistant to both SXT and bacitracin

Answer 28

Group B Strep

Question 29

Susceptible to SXT

Answer 29

Other B-hemolytic streptococci

Question 30

Differentiates Streptococcus pneumoniae from other alpha-hemolytic streptococci

Answer 30

Optochin Susceptibility Test

Question 31

______________ organism is optochin sensitive forming a > 14mm ZOI around the optochin disk

Answer 31

Streptococcus pneumoniae

Question 32

Detects the pyrrolidonyl arylamidase enzyme, which hydrolyzes the PYR substrates, producing a red color

Answer 32

PYR Test

Question 33

PYR positive microorganisms

Answer 33

Group A Streptococci, Enterococcus spp., Some staphylococcus and enterobacteriaciae

Question 34

PYR negative microorganisms

Answer 34

Group B Streptococci, and other non-group A, B, D streptococci

Question 35

Identifies bile-esculin positive bacteria like Group D Streptococci and Enterococcus spp

Answer 35

Bile Esculin Agar Test

Question 36

Positive reaction for Bile Esculin agar test

Answer 36

Dark brown/ black coloration

Question 37

Distinguishes S. pneumoniae from other A-hemolytic streptococci

Answer 37

Bile Salt Solubility test

Question 38

Turner and Schwartz +1 on Coagulase test

Answer 38

have small unorganized clots

Question 39

Turner and Schwartz +2 on Coagulase test

Answer 39

have a small organized clot

Question 40

Turner and Schwartz +3 on Coagulase test

Answer 40

feature a large organized clot

Question 41

Turner and Schwartz +4 on Coagulase test

Answer 41

entire contents of the tube coagulated & unable to be displaced when the tube is inverted

Question 42

_______________ wire loops will cause false positive on Oxidase Test

Answer 42

Steel and nickel

Question 43

Oxidase Test must be used not older than ________________

Answer 43

1 week

Question 44

PYR Positive result will have the development of a ______________________ color within a minute of addition of the reagent

Answer 44

deep cherry red

Question 45

PYR test stands for

Answer 45

L-Pyrrolidonyl- β-naphthylamide

Question 46

A positive reaction ninhydrin test is indicated by the appearance of a ___________________ within 30 min

Answer 46

deep blue color (about the shade of crystal violet)

Question 47

The addition of bile salts also activates the ______________ and accelerates the natural lytic reaction observed with cultures of pneumococci.

Answer 47

autolysins