Lab Research for Mini Session Microbiology at Franciscan University : Day 9: 5/27

MR-VP Test:

Today we kicked off Lab by redoing the MR-VP test. Due to our blunder of the following lab we had to reinnoculate a tube of broth for these two tests. We separated the broth into two tubes using a pipet for the two tests.

For the Methyl Red test (MR) we added 5 drops of methyl red into one of the tubes. Immediately we observed and the results were negative, signaled by a yellow-orangish color of the broth. This test was to determine the ability of our bacteria to ferment glucose via mixed acid fermentation. These acids lower the pH of the medium to below 5 and when the methyl red was added it was changed in our broth because the pH was higher due to lack of acid fermentation and less acid is present, therefore our broth turned yellow. Our test was negative.

For Part two of this test, the Vogues-Prokauer test, we tested to see how our bacteria ferments glucose via buntanediol fermentation. To the second tube we added 15 drops of Barrit's reagent A ( 1% alpha-naphtol in ethanol) and 5 drops of Baritt's reagent B (40% KOH).

These two reagents will react with acetone produced during glucose fermentation in the presence of oxygen and form a red precipitate. A red color means a positive test. After waiting thirty minutes our test was positive, meaning our bacteria uses butanediol during glucose fermentation.

Swabs and Urine:

Next we did a Throat Swab, Nasal nares swab, and Urine sample
For the Throat swab Eleni used a tongue depressor and a sterol cotton swab and touch the back of Theresa's throat (touching the uvula and avoiding contact with the tongue) and then she inoculated a Blood agar plate to test for Streptococcus aurelis (maybe Theresa still has it? we'll find out)

Theresa's Previous Throat Culture Sample

Then for the Nasal nares swab Theres took a cotton swab and after dipping it in saline solution because a dry swab would not be effective. Then Theresa inoculated a Mannitol salt plate to test for MRSA.

Finally Eleni graciously supplied us with a urine sample and using a 50 microliter pipet placed the urine onto a EMB sample. Using a sterilized loop (thanks to the trusty Bunsen Burner) spread the urine over the plate.

We placed all three of these plates into the 37 Celsius incubator to see what unfriendly microorganisms are growing in our friends.

Kirby-Bauer Test:

This test was to see the results of antibiotics and home remedies on our bacteria
After inoculating a nutrient agar plate with the still unknown bacteria "N"

We added the following antibiotics to the nutrient agar plate:
1. Penicillin (which effects the cell wall)
2. Tetracycline (protein synthesis)
3. Neomycin (protein synthesis)
4. Cinnamon oil (yum)
5. Lemon oil (also yum)
6. Augmentin

For the first three drugs we used small forceps, a small beaker filled with ethanol and a bunsen burner to sterilize the forceps. After marking a chart of where each antibiotic was, we placed three paper discs of the drug onto the plate with the sterilized forceps (that had been dipped in the alcohol and placed over the bunsen burner flame) .