An Unknown Microorganism Using Biochemical Tests

1943 WordsMay 5, 20168 Pages
Identifying microorganisms can provide information on diagnosing diseases and discovering the most beneficial treatment possible. The purpose of this assignment was to identify an unknown microorganism using biochemical tests and various methods that were practiced in the microbiology laboratory. In this paper, I will discuss the processes of how I came to identify my unknown microorganism. For this experiment, I utilized unknown number three which I later identified as Staphylococcus epidermis. I concluded that the unknown organism was Staphylococcus epidermis based on numerous tests performed in the laboratory which I will discuss in detail throughout this paper. One of the first tests performed was the Gram Stain. The Gram Stain differentiates bacterial organisms according to their cell wall structure. Gram-positive cells will stain blue to purple whereas Gram-negative cells will stain red to pink (Lab Handout; Gram Stain). Upon performing the Gram Stain on my unknown, I concluded that it was a Gram-positive cell due to the purple color when viewed under the microscope. I also determined the shape to be cocci as evidenced by the spherical shape of the bacterium. In the following picture viewed with an electron microscope, you can clearly see that Staphylococcus epidermis is a Gram-positive cocci (microbiologyglossary.wikispaces.com). The Gram- positive cocci are arranged in grape-like clusters and are non-motile. They also form cohesive, white and raised colonies
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