Microbiology- Unknown Bacteria of throat
Lab Report for the Identification of Bacteria Associated with the Throat
Directions: Your throat unknown is one of the following bacteria: Staphylococcus aureus or Staphylococcus epidermidis. Your lab report will consist of the following:
1- A Table (25 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. (meaning what reaction took place resulting in an observable change)
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. You need to include all of the organisms that give the result you listed in (b).
e) For your report, you will submit a typed version of your table.
2- A Written Report- Discussion
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. Do not include information about the procedures you conducted. The steps for writing your discussion are:
a) List the possible unknown throat bacteria used in this laboratory exercise. (5 points)
b) Discuss of 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) Discuss the tests that clearly identify your unknown, giving reasons why certain organisms are excluded (eliminated) as your unknown, and how you reached your specific decision on the identity of your unknown. Begin with the blood agar, mannitol salt agar, & DNase agar test results for a presumptive identification of the unknown. (30 points)
Note: you do not have to include catalase in your written discussion. IN addition, once you have eliminated a possible organism, you do not need to continue to discuss it in your report.
d) Use the coagulase test to make the critical diagnostic decision for the identity of your unknown. (10 points)
e) State unknown number and the identity of your unknown. (10 points)
f) Conclude your report with a summary statement of one to two sentences of how you were able to identify your unknown. Include specific test results that revealed the identity of your unknown. (10 points)
