A second isolation was completed and when observed there were only two bacteria’s growing.
After isolating one of the bacterium a Gram stain was performed.
The next biochemical test that was performed was a H2S test.
After observation, the H2S test had a negative result, which pointed to Escherichia coli.
The proper procedure for all of these tests can be found in the laboratory manual.
Table 1 lists the test, purpose, reagents and results for culture #1.The second culture’s results were also found with the help of the unknown chart, handed out by the instructor.However, like stated earlier, a problem was faced after the isolation was incubated.The two microorganisms were identified; one was a Gram-positive bacteria, the other was a Gram-negative bacteria.A series of biochemical tests were performed based on the results of the Gram stains.A third test was done in order to confirm that Escherichia coli is the unknown.The Urea test also had a negative result, which confirmed that the unknown #1 is Escherichia coli.The laboratory manual, by Mc Donald, includes all the procedures used for these methods (1). This was completed by taking an inoculating loop and spreading the unknown out on to a Nutrient Agar plate.This was done using the streak plate method, which is described in the lab manual.Table 2 lists the test, purpose, reagents and results for culture #2.All of the following tests were performed on culture #1: RESULTS: In unknown tube #125 culture #1 appeared to be a white cloudy streak on the plate. Culture #2 appeared to be solid white dots spread out on the plate. The results of the Gram stain determined which biochemical test to use in order to identify the microorganisms.