3.3.2: SIM Medium Test Activity

In this activity you will test five bacterial samples.

1. Turn on the Bunsen burner and sterilize the inoculating needle by passing it through the flame of the burner.
2. Gently raise the lid to the agar plate containing the bacterial culture to be sampled and touch the inoculating needle to a bacterial colony to obtain a bacterial sample.
3. Pick up the SIM tube to which the sample is to be transferred. Remove the cap and pass the mouth of the tube through the flame of the Bunsen burner.
4. Insert the inoculating needle by stabbing straight down into the media all the way to the bottom of the media, and then gently remove the inoculating needle so as not to disturb the stab mark.
5. Pass the mouth of the SIM tube through the flame and recap it, and return it to the test tube rack.
6. Sterilize the inoculating needle by flaming the loop in the flame of the Bunsen burner. Repeat steps 1 - 8 for the other four bacterial species and SIM tubes to be inoculated.
7. Incubate the inoculated SIM tubes at 37°C for 24 hours.
8. At 24 hours add 5 – 6 drops of Kovac’s reagent to each of the incubated SIM agar tubes.
9. After approximately 1 minute observe the SIM tubes for color changes, precipitation formation, and cracks in the media. Use the chart as a guide and record your results in the table below.

In the table below write the name of the species tested and the results for each of the tests performed.

Experimental Results

Bacterial Species	H2S Production (Color and Test Result)	Indole (Color and Test Result)	Motility Test (Growth pattern and Test Result)

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