Dichotomous Key Assignment Biochemical Test Results Acid-fast: positive Methyl Red (MR): positive Bacitracin: Motility: resistant Catalase: positive positive NO3 reduced to NO2: positive Citrate Utilization: negative Novobiocin: Coagulase Tube Test: negative Optochin: Facultative anaerobe: positive Ornithine decarboxylase: negative Glucose fermentation: negative PYR: Hemolysis: alpha Starch hydrolysis: Indole: Trehalose fermentation: positive positive susceptible sensitive positive positive Lysine decarboxylase: positive Voges Proskauer (VP): negative Mannitol fermentation: positive Xylose fermentation: negative Scenario #1: You are handed an unknown and after Gram staining determine the microbe is a Gram Positive Rod. a) b) c) d) What flowchart is to be used to identify the unknown? What is the first biochemical test that is to be performed? Using the results of the biochemical tests above, what is the unknown bacteria? If an error was made in the catalase test and it was instead negative, what now is the unknown bacteria? Scenario #2: You are handed an unknown and after Gram staining determine the microbe is a Gram Positive Coccus. Again, use the biochemical test results provided to answer the following questions. a) b) c) d) What flowchart is to be used to identify the unknown? What is the first biochemical test to perform once on this flowchart? What is the unknown bacteria? The key for the flowchart reminds students what exercise describes each of the biochemical tests. What exercise is Voges-Proskauer? Scenario #3: You are handed an unknown and after Gram staining determine the microbe is a Gram Negative Rod (Enterobacteriaceae). a) Enterobacteriaceae may use one of several charts. What test(s) must first be performed to determine what chart to use? (Hint: pg 557) b) Again using the biochemical test results provided, what flowchart is to be used to identify the unknown? c) What is the first biochemical test to perform? d) What is the unknown bacteria? e) If an error was made in interpreting the Xylose fermentation results and it was instead positive, now what is the unknown bacteria? Scenario #4: You have identified your unknown as Streptococcus mutans. What tests would you have had to perform in order to get this as your answer? List ALL of them in order of completion.