Microbiology lab practical exam 2
The gram stain showed clear purple gram positive cocci.
MICROBIOLOGY LAB PRACTICAL EXAM 2 MANUAL
A sample was taken from the isolated nutrient agar and a gram stain was done as directed by the lab manual (1). After incubation, this nutrient agar had great results with many isolated colonies. A sample was taken from this colony and transferred to a nutrient broth agar to further isolate it. This test was also incubated at 37 degrees Celsius for 48 hours and returned a good isolated colony. Professor Snaric advised to do another MSA agar from the original stock, but this time with a sterile swab instead of an inoculating loop. Upon return and observation, the MSA did not yield a good isolated colony. This MSA plate was incubated at 37 degrees Celsius for 48 hours. Returning to the original unknown stock 123, a quadrant streak plate was done with a sterilized inoculating look on a mannitol salt agar, which inhibits the growth of gram negative bacteria. After confirming the gram negative bacteria, the process of isolating the gram positive bacteria began. After observation there was a clear positive result, which showed the bacteria produced casease. The milk agar was incubated at 37 degrees Celsius for 48 hours. Upon reviewing the identification tables, the deciding biochemical test was the Casein test which tests for the production of the enzyme casease to break down the milk protein casein. From previous biochemical tests done in the semester, Pseudomonas aeruginosa was already suspected because of the green pigment of the original streak plate. To decipher between which biochemical tests to perform, the gram positive and negative tables handed out by the Professor, were referred to. The gram stain showed a result of red, gram negative rods. The gram stain procedure was performed as directed in the lab manual (1). As well as using the quadrant method to further isolate the colonies, a sample was taken from the best colony on the original streak and gram stained. After observation, a sample was taken from the isolated colony on the streak plate and another streak plate was done with that, trying to further isolate the colonies. There was only one colony that was apparent. Upon returning and observing the streak plate, there was an abundance of green across the plate. The streak plate was then incubated at 37 degrees Celsius for 48 hours. After removal with bacteria on the loop, the quadrant streak method was used. In order to do the streak method, an inoculating loop was sterilized with a Bunsen burner and put into the unknown specimen. The streak method was used to spread the bacteria across the nutrient agar in hopes of isolating a pure culture of one of the bacteria. In order to do this, a nutrient agar plate was used. The first step to figuring out the unknowns, was to separate the two bacteria. At this point everything that had been learned in microbiology lab and that had been explained in our lab manual (1) was put into action. The unknown number 123 handed out by the Professor on Macontained both a gram positive bacteria and a gram negative bacteria. These bacteria must be able to be identified in order to treat patients properly, efficiently and safely. In the medical field bacteria and infections of different kinds are the core of the practice. This will be a vital task to take with me into my profession for many reasons. In this paper I will discuss the processes of how I came to find my two unknown bacteria. Example of a Microbiology Unknown Lab Report by Taylor Autry