Lab Final Exam Flashcards
How is the Catalase Test performed?
What does it test for?
a) Place bacteria on a glass slide and add a drop of hydrogen peroxide
b) This test is used to differentiate between gram positives
What will a positive reaction for Catalase look like?
A negative reaction?
+ Catalase - Bubbles
- Catalase - No reaction
How is the Lactose, Sucrose, and Dextrose Test performed?
What does it test for?
a) Obtain a lactose, sucrose, and dextrose tube, inoculate each type of broth
b) This tests for acid production and gas production
What will a positive reaction for Lactose, Sucrose, and Dextrose look like?
A negative reaction?
+ Acid production - Yellow
- Acid production - Red
+ Gas production - Bubbles
How is the TSI Test performed?
What does it test for?
a) To perform this test, aseptically use an inoculating needle to stab and streak TSI agar slants with the bacteria given before incubating.
b) TSI tests for sugar fermentation and hydrogen sulfide production.
What will a positive reaction for TSI look like?
A negative reaction?
+ Sugar Fermentation - Yellow
- Sugar Fermentation - Red
+ Hydrogen Sulfide - Black
- Hydrogen sulfide - No color
How is the Blood Test performed?
What does it test for?
a) This test is performed by aseptically transferring bacteria onto blood agar plates. This should be done with an inoculating loop.
b) This tests for the enzyme hemolysin.
What will blood Hemolysis results look like?
Beta hemolytic - Clear ring is formed around the
colonies
Alpha Hemolytic - Discoloration, green pigment. Do not
produce hemolysin
Gamma hemolytic (y-hemolysis) - No Change
How is the Mannitol Salt Test performed?
What does it test for?
a) A streak plate is prepared aseptically using an inoculating loop to transfer bacteria.
b) This tests for whether or not a species of bacteria can ferment sugar mannitol.
What will a positive reaction for Mannitol Salt look like?
A negative reaction?
Red - Negative Mannitol fermentation
Yellow - Positive Mannitol fermentation
How is the Eosin Methylene Blue Test performed?
What does it test for?
a) Prepare a streak plate using an inoculating loop, transfer bacteria aseptically, and incubate.
b) Differentiates enteric bacteria based on lactose fermentation and acid production
What will a positive reaction for Eosin Methylene Blue look like?
A negative reaction?
+ Lactose fermentation - Dark purple colonies
- Lactose fermentation - Colorless colonies
+ Lactose fermentation - Metallic green colonies
AND + Acid production
How is the Citrate Test performed?
What does it test for?
a) Culture agar slant tubes, stab and streak
b) Tests for citrate carbon source
What will a positive reaction for Citrate look like?
A negative reaction?
- Citrate - Green
+ Citrate - Blue
How is the Methyl Red/Voges-Proskauer Test performed?
What does it test for?
a) Culture 2 MRVP broth tubes, separate into 4 after incubation and add 3 drops of MR to MR tubes. Add 15 drops of A and 5 drops of B into VP tubes.
b) Methyl Red (Acid production)
Voges-Proskauer (Acetoin production)
