The purpose of this lab was to determine which carbohydrates a bacterium can use on
three different specimens. The acid from glucose test is done to see if the microbe can ferment
the glucose a carbon source. The lactose fermentation test was performed to see if the microbe
can ferment lactose as a carbon source and the sucrose fermentation test was performed to see if
the microbe can ferment sucrose as a carbon source. I tested each of the bacterium for glucose,
lactose and sucrose as carbon sources. In the first case study I was presented with water from the
Baker ranch that was provided from a pond that they used to give the cattle to drink as the
earthquake had opened up a natural spring. The tests I conducted came back positive for glucose,
sucrose, and lactose. It was negative for gas, and contained a gram negative rod stain. The
second case was a boy dropped a slice of watermelon on the ground of the barn and rinsed it off
with water then proceeded to try to eat it when the nurse in charge took it away from him
because it was not good to eat it and wanted to test it to prove that fact. The tests I conducted
came back positive for glucose, sucrose, and lactose. It was negative for gas, and contained a
gram negative rod stain. The third case was a flight attendant who presented with a cold,
followed by fever and joint paint the following day. The tests I conducted came back positive for
glucose. It was negative for lactose, sucrose, and gas. It was also a gram negative rod stain. The
fourth case I was given was a cow who had red, swollen udders. The tests I performed were
positive for glucose, negative for sucrose, lactose, and gas. It was also a gram negative rod stain.
Procedure: Part 1 –
Conduct four biochemical tests on bacterium sample, TestBacterium1.
Conduct Acid from Glucose and Gas from Glucose Tests:
1. Click on the New Unknown button and type TestBacterium1 in the “enter a label” field. Select
Media Tests 1 from the Subgroup dropdown menu. Select the box allowing autoinoculation.
2. Record your Case Study.
, 3. The Gram Stain window will open. Record the results of the Gram Stain.
4. Open the Biochemical Tests Reference Book. (You can find this resource in two way; you can
click on the T? button or select the Reference Books from the Help dropdown menu.)
5. Open the Acid from Glucose test. Review the steps of the test and determination of test results
before you begin your experiment.
6. From the Media dropdown menu, select Phenol Red Glucose Broth Durham Tube. The Media
dropdown menu is to the far right of the New Unknown button.
7. Enter Phenol Red Glucose in the Medium Label window to label your sample. Click OK. Two
tubes will appear on your workbench. Take a careful look at the sample tube (the one on the
right.) Is there media in the Durham Tube (this is the tube that is upside down in the medium.)
8. Turn on Bunsen burner by right clicking on the Bunsen burner and hitting on. You will see the
flame of the Bunsen burner.
9. Select Loop from the Tool dropdown menu. Flame the wire in the flame of the Bunsen burner
until it glows red.
10. Bring wire over to Inoculum sample (the sample on the left). Right click on sample and
select Inoculate.
11. Check the Traffic Signals in the upper right hand corner of the lab. Check to see that you
have successfully inoculated your sample and that no contamination was introduced.
12. Turn off Bunsen burner.
13. Select Pointer tool from Tool menu.
14. Put cursor, with your Pointer tool, over your inoculated sample, drag it, and place it in the 37
degree incubator. You will also see that your inoculum sample will “disappear” from the
workbench.
15. Click the New Day button. Notice that the Virtual Days counter now reads 2.
16. Put cursor over the incubator. Right click and select your sample, Phenol Red Glucose. Your
sample tube will appear on your workspace.
17. Right click on tube and select Record Results. NOTE: You will record results for two tests –
Acid from Glucose and Gas from Glucose. NOTE: Is there media in the Durham Tube?
Making note of this is important in recording the correct results. Refer to the Gas from
Glucose Test in the Biochemical Test Reference Book.
18. After you record your results, the sample tubes are automatically disposed of in the
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