Create a dichotomous key in the form of a flowchart using the information provided in the table. You must separate each bacterium from another using the lower number of test results possible.

Question

Background information:

You learned that in the laboratory we can perform testing to identify the identity of isolated bacteria. Laboratory technicians are very directed in their testing and create dichotomous keys based on expected test results to expedite the identification of isolated bacteria. 

The table below contains a short list of bacteria and the expected results for laboratory test such as Gram staining, capsule staining, acid fast staining, flagellar staining and endospore staining.

Instructions: Create a dichotomous key in the form of a flowchart using the information provided in the table. You must separate each bacterium from another using the lower number of test results possible.

Bacterial Name	Gram Stain Result	Cell Morphology	Capsule Staining: for the Presence of Capsule	Acid-Fast Staining: for the Presence of Mycolic Acid	Endospore Staining: for the detection of Endopores	Flagellar staining: for the presence of flagella
Staphylococcus hominis	Positive	cocci	No	No	None	None
Mycobacterium tuberculosis	Positive	bacilli	No	Yes	None	None
Bacillus thuringensis	Positive	bacilli	No	No	Yes	Yes, multiple
Campylobacter	coli	Negative	bacilli	No	No	None	Yes, multiple
Neisseria meningitidis	Negative	cocci	Yes	No	None	None

 

 

Answer 1

Gram Stain first will make it so you will have 3 positive and 2 negative organisms. Next Morphology will separate the two negative organisms. On the Gram positive side do morphology which will separate out S. hominis. You still have to separate tuberculosis and thuringensis. Use acid fast stain to separate those. If this doesn't make sense let me know and I will make a video.