The Enterobacteriaceae and Other Related Enterobacteria

Question 1

On MAC:

Typical strong lactose fermenters produce

Answer 1

red colonies surrounded by a zone of precipitated bile

Question 2

On MAC:

Slow or weak lactose fermenters produce

Answer 2

light pink colonies or colonies that are clear at the periphery and have pink centers

Question 3

On MAC:

Non-lactose fermenters produce

Answer 3

colorless colonies or transparent colonies

Question 4

On EMB:

Typical strong lactose fermenters produce colonies that are

Answer 4

green-black with metallic sheen

Question 5

On EMB:

Slow or weak lactose fermenters produce

Answer 5

pink to purple colonies

Question 6

On EMB:

Non-lactose fermenters produce

Answer 6

colorless colonies or transparent colonies

Question 7

On SSA:

Slight growth of lactose fermenters that produce

Answer 7

pink or red colonies

Question 8

On SSA:

Salmonella and Proteus colonies are

Answer 8

colorless with black centers

Question 9

On SSA:

Shigella colonies are

Answer 9

colorless with no blackening

Question 10

1. Triple Sugar Iron Agar Reactions

is indicated by the retention of the original red color of

Answer 10

Alkalinization or nonfermentation of the carbohydrates

Question 11

designates alkaline reaction; designates acidic reaction

Answer 11

“K”; “A”

Question 12

indicated by a change in the color of the medium from red to yellow and this may be observed in the butt portion only or throughout the medium

Answer 12

Acid production from fermentation of carbohydrates

Question 13

indicated by gas bubbles or splitting of the agar in the butt portion

Answer 13

Gas production

Question 14

indicated by a black discoloration of the medium which first appears or remains confined in the butt portion

Answer 14

Hydrogen sulfide (H2S)

Question 15

alkaline slant and bua, no gas and H2S producTon

Answer 15

K/K

Question 16

alkaline slant, acid bua, with gas and H2S producTon

Answer 16

K/Ag + H2S

Question 17

acid slant and bua, with gas, no H2S producTon

Answer 17

A/Ag

Question 18

INDOLE TEST: Reagent

Answer 18

15 drops of Ehrlich’s (+ 1 ml of xylene or chloroform) or Kovac’s reagent

Question 19

INDOLE TEST: Positive result

Answer 19

Bright fuschia red color at the interface of the reagent and the broth (or xylene layer)

Question 20

INDOLE TEST: Negative result

Answer 20

Yellow color or no color change

Question 21

METHYL RED TEST: Reagent

Answer 21

5 drops of methyl red indicator

Question 22

METHYL RED TEST: Positive result

Answer 22

Red color on the surface of the medium

Question 23

METHYL RED TEST: Negative result

Answer 23

Yellow to orange color

Question 24

VOGES-PROSKAUER TEST: Reagent

Answer 24

0. 6 ml of 5% alpha-naphthol

0. 2 ml of 40% KOH

Question 25

VOGES-PROSKAUER TEST: Positive result

Answer 25

Red color

Question 26

VOGES-PROSKAUER TEST: Negative result

Answer 26

Yellow color or no color change

Question 27

SIMMON’S CITRATE UTILIZATION TEST: Positive result

Answer 27

Prussian blue or deep blue color

Question 28

SIMMON’S CITRATE UTILIZATION TEST: Negative result

Answer 28

No color change (retention of green color)

Question 29

Diffuse growth outward from the stab line or turbidity throughout the medium

Answer 29

Motility

Question 30

To detect indole production, add 3-4 drops of Ehrlich’s or Kovac’s reagent, and observe for a pink to red color

Answer 30

Indole production

Question 31

is detected in the butt by an alkaline (purple) slant

Answer 31

Lysine decarboxylation

Question 32

detected by a red slant

Answer 32

Lysine deamination

Question 33

detected by formation of a black precipitate

Answer 33

Hydrogen sulfide (H2S) production

Question 34

K/K

Answer 34

alkaline slant and butt, and NO H2S production

Question 35

K/K + H2S

Answer 35

alkaline slant and butt butt, and H2S producTon

Question 36

R/A

Answer 36

Red slant, acid butt, and NO H2S producTon

Question 37

K/A

Answer 37

alkaline slant, acid butt, and NO H2S producTon

Question 38

K/A + H2S

Answer 38

alkaline slant, acid bua, and H2S producTon