Microbiology
Clinical Unknown #3
Identification of Bacteria Associated with the Urinary Tract
Directions: Your urinary tract unknown is one of the following bacteria: Enterococcus faecalis, Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa or Staphylococcus epidermidis. Your lab report will consist of the following:
1- A Table (30 points)
a) Record your observations in the table for each test performed to identify your unknown. In the column labeled “Observations” write what you saw (for example, a color change, the presence or absence of growth, a particular growth pattern).
b) Record your results in the table for each test performed to identify your unknown. In the column labeled “Result” write whether your unknown is either positive or negative for a particular enzyme or metabolic activity.
c) In the column labeled “Explanation of Observation/Result”, write a brief explanation of the reaction observed.
d) In the column labeled “Organism(s) Indicated”, write the name(s) of all the organism(s) indicated by the result you wrote on your table.
e) For your report, you will submit a typed version of your table.
2- A Written Report
You will attach a discussion of your results to the table. This is the most important part of your unknown identification project.
This portion of your report is to be typed, double spaced, and submitted by the next lab session.In your discussion, focus on how you identified your unknown based on a process of elimination.
The steps for writing your discussion are:
a) List all possible UTI bacteria used in this laboratory exercise. (5 points)
b) Discuss your Gram staining results; describe if your Gram staining results allowed you to eliminate any of the possible bacteria as your unknown. (10 points)
c) Describe the observations and results for lactose fermentation using MacConkey and EMB. Distinguish fermenters from non-fermenters. Based on your results, explain what bacteria can be excluded & included as your UT unknown. (20 points)
d) Discuss several tests that clearly allowed you to identify your unknown. Give reasons why certain organisms are excluded, and how you reached your specific decision on the identity of your unknown.
Do not include a description of all the tests you performed.
Include only the most relevant tests, how they allowed you to eliminate the remaining bacteria that were not previously excluded and determine the identity your unknown. (20 points)
e) State the unknown number and the identity of the unknown. (10 points)
f) Conclude your report with a summary statement. (5 points)
