Lab Exercise 2 - lab work PDF

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Lab Report 2 Name: __Michele Glantz__ Date: ___5/15/19_______

Aseptic Techniques Your Results and Observations 1. Describe and draw the growth of your organisms on the nutrient agar slants; be sure to include the organisms’ names. Organism

Describe (and draw if needed) the form or margin of the growth (see which part of figure 2.7 is most similar to your growth)

Staphylococcus aureus

Growth represented edge Characteristics of lobate

Bacillus cereus

Growth represented edge characteristics of lobate

Escherichia coli

Growth represented edge characteristics of entire

Micrococcus luteus

Growth represented edge characteristics of undulate

2. Describe the form of growth observed in the tryptone broth tubes of your organisms (terms you might use include turbidity, flocculent, sediment, ring, and pellicle). In the broth, Escherichia coli exhibited turbidity, meaning the tube was cloudy. In the broth containing Bacillus cereus, the growth, or sediment, has settled at the bottom. 3. Describe and draw the growth of your organisms on the Petri dish; be sure to include the organisms’ name. Bacillus cereus exhibited lobate edge characteristics.

Escherichia coli exhibited entire edge characteristics.

Lab Report 2 4. Would cultural characteristics like colony morphology be of value to a clinical microbiologist? How could they be used? Cultural characteristics would definitely be of value to a clinical microbiologist because they help to identify a certain bacterium so the appropriate treatment may be used. 5. Were your cultures consistent in appearance? How could you confirm your culture was a pure culture? Where during the process of aseptic transfers could contaminants be introduced? The cultures were consistent in appearance. The culture was pure because they had the same color, transparency, elevation and edge. The test tube cap is a source of contamination as well as not sterilizing the loop before and after transfer.

6. Jane was very careful in performing her Petri dish inoculation. When she examined her plate during the next lab period, a fuzzy white colony was growing on her plate, but not along her inoculation streak. What happened? Where did this colony come from? Contaminants were introduced. The colony came from somewhere on her plate cover possibly when she placed it down. 7. Jeffrey, Jane’s partner, inoculated a tryptone broth tube with E. coli. When he examined his broth tube during the next lab period, there was no growth at all. What could have gone wrong with his experiment? After sterilizing the loop, the loop may not have been cooled long enough. This may have killed the bacteria. 8. In the case file, the organism responsible for the patient’s death is a normal member of the human microbiota. How do you explain it causing the death of this patient? It was introduced into an area where the microbiota is not found. The microbiota is normally found in the oral cavity and intestinal tract. 9. What is the connection of the events described in the case file and today’s laboratory activity on aseptic technique? In the case file and the laboratory activity, aseptic techniques are used to prevent contamination. Bacteria are ubiquitous, meaning they are found everywhere. Using aseptic technique helps to both prevent and spread any contamination.

Lab Report 2...