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Biology LibreTexts

2.3: Results

  • Page ID
    15960
  • Record the results of your experiments in the tables below.

    A. Observation of growth characteristics on selective and differential media

    Mannitol salt Agar
    Bacteria Growth (+/-) Describe growth characteristics Interpretation
    S. aureus
    E. coli
    P. aeruginosa
    M. luteus
    EMB Agar
    Bacteria Growth (+/-) Describe growth characteristics Interpretation
    S. aureus
    E. coli
    P. aeruginosa
    M. luteus

    B. Inoculation for single colony isolation

    Tryptic Soy Agar
    Bacteria Growth (+/-) Describe growth characteristics
    S. aureus
    E. coli
    P. aeruginosa
    M. luteus

    C. Isolation of single colonies from mixed cultures

    Unknown A: Describe growth characteristics on MSA and make a sketch in the circle below.

    circle.png

    Unknown B: Describe growth characteristics on EMB and make a sketch in the circle below.

    circle.png

    Based on your results, answer the following questions:

    1. How effective was the streaking procedure in separating the different types of bacteria?

    2. What conclusions do you have regarding the types of bacteria in the unknowns?

    Unknown A

    Unknown B

    D. Environmental Sample

    Record the results of your own environmental sample and the other sample at your bench in the two tables below.

    Your environmental sample from ______________________________________

    Growth (+/-) Describe growth characteristics
    TSA
    EMB
    MSA

    Lab partner environmental sample from ____________________________________

    Growth (+/-) Describe growth characteristics
    TSA
    EMB
    MSA

    Answer the following questions and provide evidence to support your answers.

    1. Did you detect any Staphylococcus species in your environmental sample?

    2. Were Gram-negative bacteria present?

    3. Were there any coliforms present? Was E. coli present?

    4. Was S. aureus present?

    5. Was there evidence for organisms other than bacteria? (Ask your instructor.) Your instructor may ask you to save some of your environmental samples for further analysis.