Microbiology Lab Report

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To determine the unknown’s morphology is the first step in narrowing down possible organisms. A MacConkey and Mannitol Salt Agar tests were conducted on the organism and revealed the following. No growth on the MacConkey plate resulting in a gram positive bacteria and the Mannitol Salt Agar result showed it could be Staphylococcus or Micrococcus. (1) A gram stain test was used in determining the shape, size and arrangement of the unknown bacteria (1). The unknown organism is heat fixed onto the slide, in order for the organism to be stained. The two stains, crystal violet and safranin are used to differentiate Gram positive and gram negative cells via their cell walls. Gram Negative cells turn red due to safranin and gram positive remain purple. Through microscopic examination, oil was added onto the 400x magnification. The unknown remained purple …show more content…
S. Aureus is an opportunistic pathogen and is resistance to immune response and antimicrobial agents via the production of coagulase enzyme (1). The coagulase enzyme can occur as either Free or bound coagulase. Free coagulase is an extracellular (within the cell) enzyme that reacts with coagulase reacting factor. This results in a similar to the conversion of prothrombin and fibrinogen in normal clothing (1). Bound coagulase is attached to the bacterial cell wall and reacts to fibrinogen in the plasma. The Fibrinogen participates, causing the cells to clump (1). There are two forms of the coagulase test consisting of test tube and slide test, the test tube test is used for the unknown experiment. An organism is taken from the unknown broth through aseptic technique and placed into the test tube; containing rabbit plasma (6). The test tube should be placed onto an incubator for no more than 24 hours; results of clumping should show within 3 hours.
Agar Deep

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