And My Bacterium Is....

       This week has been a crazy one since there is no school on Monday due to Veteran's Day. However, I still was able to identify my unknown bacteria. Last Friday I performed the SIM (Sulfide-Indole-Motility) test, and predicted that my unknown was Escherichia coli. For this test, you inoculate a sterile needle with your sample, and stab it through the testing media and incubate. Here are the results of the test.

SIM Test Results

To read the test, we look to see if there is any black coloration around the inoculation site. My sample did not, so it is negative for sulfur. Next is motility; when you first inoculate the medium, it is a clean line through. If there is a blurry cloud around the site, as is my sample, it is positive for motility. Therefore, negative sulfide and positive motility on the dichotomous key I was given indicates that my bacterium is....

Escherichia Coli!! 

I knew it!