Simmons Citrate Test Pg95-96

Question 1

The ability of some bacteria to utilize citrate as a sole carbon source is tested for using

Answer 1

Simmons citrate

Question 2

Simmons citrate agar contains _______ as the sole carbon source, ammonium salt instead of amino acids as the sole nitrogen source and a pH indicator:____________

Answer 2

-contains citrate
- bromythmol blue

Question 3

Bromythmol blue is what color at neutral pH and turns what color above pH 7.6

Answer 3

Green at neutral pH
Turns blue above pH 7.6

Question 4

In a positive citrate test, heavy growth generally turns the bromythmol blue indicator in the medium to a….. (what color?)

Answer 4

Deep Prussian blue

Question 5

This occurs because growing bacteria produce alkaline products from the _________ in the medium

Answer 5

Ammonium salts

Question 6

What type of growth occurs in a negative reaction and what is the color of the agar?

Answer 6

There is little to no growth and the color of the agar remains unchanged (green)

Question 7

Sodium citrate equation

Answer 7

Citratase
Sodium citrate (Na C6H8O7)——————> Acetate (C2H4O2)+ Oxalacetate (C4H4O5)

Question 8

Procedure: what bacteria is being used with the Simmons citrate agar slants?

Answer 8

E. coli and E. aerogenes

Question 9

Procedure: how long are cultures incubated for at 37 degrees Celsius?

Answer 9

48 hours

Question 10

Results:

Answer 10

Medium: Simmons citrate agar
Substrate: citrate
Reagents post-incubation: bromythmol blue
+ End prods: acetate and oxalacetate
+ appearance: blue
- appearance: green

Question 11

Was the citrate utilized for E.coli?

Answer 11

Citrate was NOT Utilized.
(No heavy growth- remained dark green

Question 12

Was the citrate utilized for E.aerogenes?

Answer 12

Yes, heavy growth (+) turned royal blue