1. Enterotube Review and Practice
MCB2010L

2. Aerobic vs. Anaerobic chambers
The first 4 chambers were sealed and contain anaerobic reactions.
The last 8 chambers contain a small window covered with plastic. We used the broken-off loop tip to puncture the plastic, allowing air to enter the chambers.
WINDOW

3. Metabolism S AA AA S S S S S/ AA AA Sulfur/ AA S = sugar metabolism
Enzyme activity (urease)
Sulfur/ AA
S = sugar metabolism
AA = amino acid

4. GLU-GAS, Chamber #1
The GLU Gas chamber MUST have a postive reaction change in color) or test is useless.
This test is for ENTERObacteria (ENTEROtube) and all have a positive reaction in chamber #1.

5. GLU-Gas: Gas production
The first 3 chambers have a wax layer to show if gas is produced.
Gas production:
The pressure of the gas caused the wax to separate from the agar.
Sometimes the gas bubble appears at the bottom, depending the position of tube during incubation.

6. Indole Test H2S/ IND chamber. Liquid indole injected.
This shows a positive result.
The test station would say:
“Assume indole test positive” or
“Assume indole test negative”.
Red color liquid

7. Reading Tube GLU/ Gas- GLU-Yellow is +, Orange is -
Gas is + if wax separates from agar, or is pushed up & swollen.
LYS- Any degree of purple is +
ORN- Any degree of purple is +
H2S/IND- H2S is the color. Dark Brown/ Black is +
IND is the injected drop. Red is +, no color change is - (you’ll be told result).
ADON, LAC, ARAB, SORB- Yellow is +, orange is - & pink is -
VP- Ignore. We don’t do this test.
DUL/PA- Green = dulcitol is - , PA is -
Yellow = dulcitol is +, PA is -
Brown/ Black = dulcitol is - , PA is +
UREA- Purple or Hot Pink is +
CIT- Blue is +

8. Practice 1
# 6
Assume the agar has swelled and pushed wax up in GLU-Gas chamber.
Assume Indole Test is Negative.

9. Practice 2
Assume the agar & wax position is unchanged in GLU-Gas chamber.
Assume Indole Test Positive.

10. Practice 3
Assume the wax separated from the agar, leaving an air space.
Assume Indole Test is Negative.

11. Practice 4 Assume gas production in GLU-Gas chamber.
Assume Indole Test is negative.

12. Answers to Practice #1 32341 #2 24540 #3 33007 #4 36261
Normally, you would be able to flip eneterotube over to look for gas in GLU-Gas chamber. # # #
Although sugar chambers appear pink, rather than orange, they are not considered the positive color change of yellow. #

13. Looking up code & Confirmatory tests
The next step is to look up the 5 digit code in the purple binder.
Confirmatory Tests are used to distinguish among possible choices for the same 5 digit number.
You will be given Confirmatory Test results & be able to choose.
5 digit code
Possible bacteria
Confirmatory test 1
Confirmatory test 2
22161
RAF VP
bacteria 1 +
bacteria 2 -
bacteria 3
V(70%)

14. 22161 RAF VP bacteria 1 + bacteria 2 - bacteria 3 V(70%) 5 digit code
Possible bacteria
Confirmatory test 1
Confirmatory test 2
22161
RAF VP
bacteria 1 +
bacteria 2 -
bacteria 3
V(70%)
1.) Confirmatory Tests show that RAF = V(70%) and VP = -. Which bacteria would it be?
2.) Confirmatory Tests show RAF = +, and VP = +. Which bacteria would it be?
3.) Confirmatory Tests show RAF = - and VP = +. Which bacteria would it be?

15. Answers to Confirmatory Tests
Bacteria 3
Bacteria 1
Bacteria 2