Identifying a bacteria based off of physical characteristics is almost impossible due to the commonality of shapes and physical features. Because of this, a wide range of biochemical tests were preformed in order to better identify the bacteria. Being able to identify an unknown was the most interesting part of the microbiology lab this semester, as well as, being able to preform the various tests. Proper aseptic technique was used throughout the semester and followed during all biochemical tests preformed, which are described throughout the paper beginning with a streak plate. A streak plate was completed first in order to isolate colonies of the unknown bacteria. This was done by pouring nutrient agar into a plate, waiting for it to solidify,
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The urea is filtered and phenol red is used as the pH indicator. When a bacterium produced urease, it can break down the urea protein into water, carbon dioxide gas, and ammonia. The urease test is used to determine ammonia production, which would appear as a bright pink color. In the phenylalanine deaminase test, phenylalanine agar was poured into a small plate and a streak was done after it had solidified. This test is used to detect amino acid breakdown and will use the energy from deaminating amino acids. Phenylalanine becomes phenylpyruvic acid and is detected by acetic iron chloride, which turned the plate green when added. If the bacteria have the phenylalanine deaminase enzyme, the bacteria will become green and considered a positive result. Although not actually done in class, the oxidase is also an important test in microbe identification. In this test, cytochrome c oxidase is used as an electron carrier and become oxidized by donating electrons to oxygen. The reagent used in this test is tetramethylphenylenediamine. When two electrons are donated, the reagent turns …show more content…
In the Kirby-Bauer test, the antibiotics chosen were rifampin, erythromycin, cefepine, chloramine, and kanamycin. The zones of inhibition showed that the bacterium was resistant to both rifampin and erythromycin and susceptible to the other three. The antiseptics used were Neosporin, Claire’s antiseptic, dial soap, contact solution, and acne cream. The bacterium was most susceptible to the Neosporin, Claire’s antiseptic, and the dial soap. While looking at many charts and dichotomous keys, I began thinking it was Escherichia Coli, but that was not one given to the class as an unknown, which narrowed it down to 4: Enterobactor aerogenes, Klebsiella oxytoca, Klebsiella pneumonia, or Serratia marcescens. A different key online allowed me to plug in all of my tests online and give a percent change for each bacterium. The bacteria it gave were Serratia liquefaciens with an 84.96% chance, Serratia marcescens with a 12.54%, and Enterobactor agglomerans with 2.5%. This leads me to believe after so many dichotomous keys that the genus would be
The urea is filtered and phenol red is used as the pH indicator. When a bacterium produced urease, it can break down the urea protein into water, carbon dioxide gas, and ammonia. The urease test is used to determine ammonia production, which would appear as a bright pink color. In the phenylalanine deaminase test, phenylalanine agar was poured into a small plate and a streak was done after it had solidified. This test is used to detect amino acid breakdown and will use the energy from deaminating amino acids. Phenylalanine becomes phenylpyruvic acid and is detected by acetic iron chloride, which turned the plate green when added. If the bacteria have the phenylalanine deaminase enzyme, the bacteria will become green and considered a positive result. Although not actually done in class, the oxidase is also an important test in microbe identification. In this test, cytochrome c oxidase is used as an electron carrier and become oxidized by donating electrons to oxygen. The reagent used in this test is tetramethylphenylenediamine. When two electrons are donated, the reagent turns …show more content…
In the Kirby-Bauer test, the antibiotics chosen were rifampin, erythromycin, cefepine, chloramine, and kanamycin. The zones of inhibition showed that the bacterium was resistant to both rifampin and erythromycin and susceptible to the other three. The antiseptics used were Neosporin, Claire’s antiseptic, dial soap, contact solution, and acne cream. The bacterium was most susceptible to the Neosporin, Claire’s antiseptic, and the dial soap. While looking at many charts and dichotomous keys, I began thinking it was Escherichia Coli, but that was not one given to the class as an unknown, which narrowed it down to 4: Enterobactor aerogenes, Klebsiella oxytoca, Klebsiella pneumonia, or Serratia marcescens. A different key online allowed me to plug in all of my tests online and give a percent change for each bacterium. The bacteria it gave were Serratia liquefaciens with an 84.96% chance, Serratia marcescens with a 12.54%, and Enterobactor agglomerans with 2.5%. This leads me to believe after so many dichotomous keys that the genus would be