The Preparation of Tests, Tests, and more Tests!

Today, we prepared more tests to identify "F" even further. While, results were not analyzed today, the preparation was a very interesting procedure!

Test #1: Gelatin Hydrolysis Test


For this test, we first used the aseptic technique to isolate a colony from our pure culture into a gelatin agar slant. We used an inoculating needle in order to transfer the colony and proceeded to gently stab the gelatin 3/4 of the way through with the needle. After, we placed the specimen into the 37 degree Celsius incubator to grow.

This procedure was completed in order to determine whether our bacteria has the enzyme gelatinase and can therefore digest gelatin. After the agar is cooled to 4 degrees Celsius, if there is liquid present in the tube, our test will be positive for the presence of gelatinase.

Test #2: Fermentation of Carbohydrates


Using the aseptic technique, we inoculated our bacteria into phenol red-sugar broth tubes with a Durham Tube (used to trap gas bubbles) inside, each containing one of three sugars: sucrose, lactose, and glucose. After the inoculation we placed each of the tubes into the incubator (37 degrees Celsius) until next time.

This test was completed in order to determine "F"'s ability to ferment particular carbohydrates. We will be able to see this depending on the color of our broths. If the broth tube changes from red to yellow or gas bubbles are trapped in the Durham tube, fermentation of the particular carbohydrate had occurred.

Test #3: Methyl Red/ Voges-Proskauer Test


For this test we used an MR-VP broth and inoculated our bacteria into the broth using the aseptic technique. Later, we placed the sample into the incubator at 37 degrees Celsius.

This test determines the bacteria's ability to ferment glucose by means of butanediol fermentation. Voges-Proskauer in the broth reacts with the acetoin produced by the butanediol fermentation changing the color of the broth from yellow to red.

Test #4: Triple Sugar Iron Agar Test (TSIA) 


This test involves the usage of Triple Sugar Iron Agar slant and the aseptic technique (no surprises there;)). After inoculating the inoculating needle we injected the needle into the agar 3/4 of the way through, smearing the needle on the top of the agar at the injection site. This was then placed into the incubator at 37 degrees Celsius.

This test will determine our bacteria's ability to ferment glucose, sucrose, and lactose and to produce an acid as a result of fermentation. Also, it more clearly differentiates between the Gram Negative Enteric Bacilli.

Test #5: Litmus Milk Test 


Using a Litmus Milk based broth we inoculated our bacteria (DON'T FORGET THE USE OF THE ASEPTIC TECHNIQUE) and placed it into the incubator at 37 degrees Celsius.

This test will determine the bacteria's ability to utilize lactose, protein, and litmus that is found in milk. Results will be determined by the color and curd formation.

Tune in next time to see these exciting results!!

ps. Check out the New Disclaimer from Franciscan University of Steubenville.