VU Lab M10 – Determining an Unknown Identity

Before starting this lab, make sure you have completed and understand all of the activities in
labs M1-M9.  You will need to understand how to choose and complete the tests from the
previous labs to successfully complete the rest of the VU labs this term.

Lab M10 Activities:

1.  Open the Virtual Unknown Software.

2.  Select and name a new unknown with the subgroup
Epidemiology 1 (make sure it is #1
or the directions will not work correctly).

3.  If you are confident that you have memorized the tube to tube inoculation procedure and
you do not need more practice transferring from tube to tube, you may click the “autoinoculation”
box from this point forward.  This will allow the computer to carry out the transfer procedure for
you after the loop tool is selected.  When the option is available, right clicking on the media tube
will show “inoculate” as an option.  If that option is not shown, make sure you have the loop
selected.  NOTE: If you remove the caps before selecting “inoculate” the computer will not
autoinoculate, you’ll have to do the whole flame and transfer procedure yourself.

4.  Read through the case and assign the
Gram stain status.

5.  Now, your job in all of the following labs is straight forward:  Identify the unknown bacterial
identity.  To complete this, you will need to make use of the Identification Matrix to choose your
tests wisely to narrow down the identity as quickly and efficiently as possible.  

* Before going any further, watch the Identification Video at the top of this page:
http://www.virtualunknown.com/vumie/help/index.htm#VUMICRO/Bacterial_Identification.htm

6.  When identifying unknowns, use 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”.  (Starting with this lab and for all
future labs, you will lose points if your identity for the unknown is incorrect.)

7.  If you forget how to do a test, or you want to do a test not previously covered, use the
directions in the T? and M? sections at the top of the lab page for directions.

8.  Identify the unknown bacteria for subgroup
Epidemiology 1.  Once you identify the
unknown, save your .pdf report to upload to the dropbox.  

9.  Next, repeat the process for a new unknown for subgroup
Epidemiology 5 (make sure
to choose #5).

10.  Identify the unknown bacteria for subgroup
Epidemiology 5.  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.  Epidemiology 1 identity: ________________________  Case study # _____________
Epidemiology 5 identity: __________________________  Case study # _____________

2.  For Epidemiology 1:  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.  What type of organism is normally infected by this bacteria?  

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 Epidemiology 5:  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.  What type of predisposing factors increase the chances of infection by this organism?  

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.  Research the term “nosocomial infection”.  Which of the above cases is most likely to
cause a nosocomial infection?  Explain your reasoning.

5.  Look over your lab reports for any errors.  Explain any errors you made and what you will
do to correct them in future labs.