Lab 6 bacterial identification Methods

Question 1

Sugar Fermentation Results

What are the types of sugars used?

Answer 1

Glucose

Lactose

Mannitol

Sucrose

Question 2

Sugar Fermentation results

(+) reaction: [two occurrences]

Answer 2

Positive:

1) color change from green to yellow due to acid production
2) Gas production

Question 3

Indole Production Results

1. What does it test for?
2. Reagent used? Why?
3. (+) reaction indication:
4. Medium used

Answer 3

1. Tests for the breakdown of amino acid Tryptone into Indole
2. Kovac’s Reagent; used for color indication
3. (+) indication: RED RING on top
4. Typtone broth

Question 4

MR-VP

1. What does MR-VP stand for?
2. For MR, add a few drops of_____ ______
3. For VP, add 5-8 drops of _______ and_______
4. How long you wait for VP reactions .]
5. Medium used

Answer 4

1. Methyl Red- Voges Proskauer
2. Methyl Red
3. alpha-napthol and KOH
4. 20 minutes
5. MR-VP

Question 5

What is the small tube used for gas production called?

Answer 5

Durham tube

Question 6

What does MR-VP test for?

Answer 6

intestinal gram-negative microoragnisms

Question 7

Nitrate Reduction

1. What does it test for?
2. reagents used
3. what is (+) indication for Nitrite NO₃^- ? NO₂^- ? N₂?
4. Medium used

Answer 7

1. Facultative anaerobic species
2. SA + DMN; Zinc dust
3. Red indication for NO₂ and NO_3; gas indication for N₂
4. Nitrate broth

Question 8

Urease Reaction

1. What does it test for?
2. Medium used
3. (+) indication

Answer 8

1. Detects the presence of the enzyme urease
2. urea broth
3. solution changes to hot pink

Question 9

Hydrogen Sulfide Test

1. What does it test for?
2. Medium used?
3. (+) indication

Answer 9

1. Production of hydrogen sulfide
2. SIM deep
3. medium turns black

Question 10

Gelatin Hydrolysis

1. What does it test for?
2. Medium used
3. (-) indication
4. (+) indication

Answer 10

1. Tests for the enzyme gelatinase
2. nutrient gelatin
3. solid
4. gelation hydrolyzed

Question 11

Citrate Utilization

1. What does it test for
2. Medium used
3. (+) indication

Answer 11

1. Ability to utilize citrate
2. Simmon citrate
3. color change to ocean blue

Question 12

Catalase Test

1. What is it testing for?
2. Medium used
3. What must be added in order to test for reaction?
4. (-) indication
5. (+) indication

Answer 12

1. Ability to produce the enzyme catalase
2. TGY agar plate
3. Must add drops of hydrogen peroxide
4. no bubbling
5. bubbling

Question 13

Starch Hydrolysis

1. What does it test for?
2. Medium used
3. What must be added in order to test for reaction?
4. (-) indication
5. (+) indication

Answer 13

1. Prescence of amylase enzyme
2. Starch agar plate
3. must add iodine
4. No zone forming
5. Zone forming

Question 14

Oxidase Test

1. What does it test for?
2. Medium used
3. What must be added in order to test for reaction?
4. How long does it take for the reaction to take place?
5. (+) indication

Answer 14

1. Prescence of oxidase enzyme
2. TGY agar plate
3. 5-10 drops of oxidase reagent
4. 2-3 minutes
5. dark blue color change

Question 15

Blood Agar Plate

1. What does it test for?
2. Medium used
3. What is Beta-hemolysis? (+) indication?
4. What is alpha hemolysis? (+) indication?
5. What is gamma hemolysis? (+) indication?

Answer 15

1. Detects hemolytic activity
2. Blood Agar plate
3. Complete breakdown of red blood cell–clear zone lysis
4. Partial breakdown of red blood cell–green/brown zone
5. No breakdown of red blood cell–no zone of lysis