Transcript File
Enterotube Review and Practice MCB2010L 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 Metabolism S AA AA S Sulfur/ AA S = sugar metabolism AA = amino acid S S S S/ AA AA Enzyme activity (urease) 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. 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. 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 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 + Practice 1 #6 Assume the agar has swelled and pushed wax up in GLU-Gas chamber. Assume Indole Test is Negative. Practice 2 Assume the agar & wax position is unchanged in GLU-Gas chamber. Assume Indole Test Positive. Practice 3 Assume the wax separated from the agar, leaving an air space. Assume Indole Test is Negative. Practice 4 Assume gas production in GLU-Gas chamber. Assume Indole Test is negative. Answers to Practice Normally, you would be able to flip eneterotube over to look for gas in GLU-Gas chamber. #1 32341 #2 24540 #3 33007 Although sugar chambers appear pink, rather than orange, they are not considered the positive color change of yellow. #4 36261 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 RAF VP bacteria 1 + + bacteria 2 - + bacteria 3 V(70%) - 22161 5 digit code Possible bacteria 22161 bacteria 1 bacteria 2 bacteria 3 Confirmatory test 1 Confirmatory test 2 RAF + V(70%) VP + + - 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? Answers to Confirmatory Tests 1. Bacteria 3 2. Bacteria 1 3. Bacteria 2