VU Lab M12 – Unknown Identity: GI Infection
Before starting this lab, make sure you have completed and understand all of the activities in
the previous labs.
Lab M12 Activities:
1. Open the Virtual Unknown Software.
2. Select and name a new unknown with the subgroup Digestive 2.
3. Read through the case and assign the Gram stain status.
4. Identify the unknown organism using the following guidelines:
* If the bacteria is Gram negative, start with the IMViC series covered in lab #M9
* If the bacteria is Gram positive, start with whichever of the following tests will eliminate the
most possibilities – OF Glucose, Growth in NaCl, or Blood Hemolysis
* When choosing tests, try to avoid tests that give results of [+] or d since they may not give
accurate results for all samples
* Continue to do tests until only one possible organism remains. If at any point you eliminate
all possibilities, return to the test that says “Remaining {0}” and redo that test.
* You can start over at any time by choosing “New Unknown”.
5. If you forget how to do a test, or you want to do a test not previously covered, use the T?
and M? buttons at the top of the lab page for directions.
6. Identify the unknown bacteria for subgroup Digestive 2. Once you identify the unknown,
save your .pdf report to upload to the dropbox.
7. Next, repeat the process for a new unknown for subgroup Digestive 3.
8. Identify the unknown bacteria for subgroup Digestive 3. Once you identify the unknown,
save your .pdf report to upload to the dropbox.
Answer each of the following questions and upload the answers to the dropbox in a
Word document, along with your two .pdf lab reports.
1. Digestive 2 identity: ________________________ Case study # _____________
Digestive 3 identity: __________________________ Case study # _____________
2. For Digestive 2: Click on the B? button at the top of the lab page then click on
Reference Books and either the Gram Positive or Gram Negative folder (whichever applies).
Find the bacteria in the list that matches the “Assigned Unknown” listed on your lab report.
a. What symptoms does infection by this bacteria normally cause?
b. This organism produces coagulase. Research the role of this enzyme and explain (in your
own words) how it helps the bacteria increase infection.
c. What details listed in the case study give clues to how this infection occurred? (You may
have to think outside the box for this last answer – remember, this program is not just used in
nursing programs, it is also used in vet programs).
3. For Digestive 3: Click on the B? button at the top of the lab page then click on
Reference Books and either the Gram Positive or Gram Negative folder (whichever applies).
Find the bacteria in the list that matches the “Assigned Unknown” listed on your lab report.
a. What symptoms does infection by this bacteria normally cause?
b. In cases of gastrointestinal illness, is this bacteria more likely to infect the upper or lower
gastrointestinal system? Explain your reasoning.
c. What details listed in the case study give clues to how this infection occurred? (You may
have to think outside the box for this last answer – remember, this program is not just used in
nursing programs, it is also used in vet programs).
4. The GI system is exposed to bacteria through the items we eat and drink. Describe two
nonspecific defenses the GI system uses to prevent most infections.
5. Research the disease "Hemolytic Uremic Syndrome". Explain, in your own words, how
bacteria cause this illness and what systems are most impacted.