Examination of Bacteria and Creating a Pure Culture

Astonishing! After two days in the incubator, our agar plates are unrecognizable. Something mysterious is thriving! Lets take a deeper look and see what we find!

This is what we observed at first glance.  The first picture is the bacteria that lives on the handle entering the women's restroom.  The latter is the bacteria that was isolated from the spout of a drinking fountain.

Examination of Bacteria:
Both samples of bacteria looked very different when viewing them under a microscope.
The bacteria on the door handle:

The bacteria found on the door handle is a cream color, even though it is hard to see that from the pictures above.  We noticed the colonies are puntiform and they are raised off the agar medium.  As seen in the picture, they are opaque; however, even though it is unable to observe in the photographs, the colonies also have a glistening appearance.  The colony margin has an irregular arrangement. This bacteria is the one we decided to use for our pure culture.

The bacteria found on the spout of the drinking fountain:

The color on this specimen varies from cream to yellow throughout the arrangement; this indicates that there is more than one bacteria found growing on the spout. Since there are so many different types, the shapes vary throughout the sample as well. The first one we discovered is puntiform and cream colored, and it is raised off of the agar medium. The second bacteria is yellow in color; its colony has a spindle form shape that is rough and embedded in the agar. This colony is flat and irregular. The last and most fascinating of the colonies is a cream concentric form bacteria. The translucent bacteria is also crateriform, being of all different levels. This particular bacteria is found in the first photograph, and we separated it for our pure culture.

Creating a Pure Culture:

After thoroughly examining our bacteria, we created a pure culture of a single colony from each sample. In order to do this we followed this process:

First, we lit the Bunsen burner and sterilized the inoculating loop.

Next, we chose a particular colony and carefully touched the tip of our inoculating loop to it, making sure not to kill the bacteria with the heated tool or intermingling it with other colonies.

After this, we streaked a single colony on a new agar plate in four different, precise motions.  They are as pictured:

Between each section we sterilized the the inoculating loop and selected the bacteria again with the tip of it once the loop had cooled.

After, we marked the new agar plate with a China marker and placed it back in the incubator to grow.  The original samples were placed in the refrigerator to remain fresh but to stunt growth.  We cannot discard them yet in case there is a misfortune with our pure cultures.

What will we find next week? Hopefully a Pure Culture of one bacteria.  Tune in to see!