A Written Report
You will attach a discussion to your table. Your report is the most important part of the unknown identification process. In your discussion, focus on the results you obtained and how you identified your unknown based on a process of elimination. The discussion portion of your report is to be typed, double spaced. You will staple the table to the written report (table first followed by the report). Please do not include information about the procedures you conducted. The steps for writing your discussion are:
a) List all possible GI bacteria used in this laboratory exercise. (2.5 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. (5 points)
Note: once you have eliminated bacteria based on Gram staining, you do not need to continue to eliminate them.
c) Discuss the results for your Durham tube fermentation tests. Describe how you used the three fermentation tubes to rule out certain bacteria. You need to describe phenol red glucose, lactose and mannitol results as one series of tests; do not describe each sugar fermentation test separately. Be sure to clearly list which bacteria are included and/or excluded based on the series of Durham tube fermentation results and give clear reasons why. (10 points)
Note: once you have eliminated bacteria based on Durham tube fermentation, you do not need to continue to eliminate them.
d) Discuss several tests that clearly allowed you to identify your unknown (these are known as definitive tests). For this part of your report, you cannot include Gram staining and phenol red glucose, lactose and mannitol since you have already discussed them in parts b and c. Give reasons why certain organisms are excluded, and how you reached your specific decision on the identity of your unknown. You should describe how you excluded bacteria that remained as your possible unknown after Gram staining and Durham tube fermentation. Do not include a description of all the tests you performed. Include only the most relevant tests and explain how they allowed you to eliminate the remaining bacteria that were not previously excluded and determine the identity your unknown. (10 points)
e) State your unknown number and the identity of your unknown. (5 points)
f) Conclude your report with a summary statement of how you were able to identify your unknown. (2.5 points)