“selective /differential media”

If we carried out the “selective /differential media” exercise in lab, we would have been inoculated the following 8 bacteria on to tryptic soy agar, sheep blood agar, MacConkey agar, Hektoen (enteric) agar and Mannitol Salt agar. You would be working in groups and each group assigned a bacterium and then you would be asked to streak plate these microorganisms on the above 5 media. Then you would be asked to observe all of the plates, with some having more importance than others.

The bacteria would be:
Gram neg.: Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa and less important for this exercise, Enterobacter aerogenes.
Gram pos.: Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus and less important for this exercise, Enterococcus faecalis.

Exercises 4-1, 4-5, 4-65/20 (formerly Ex. 20) Document
Reminder: On trypticase soy agar – Staph. aureus and Micrococcus luteus colonies were somewhat golden in color and opaque. E. coli and Proteus vulgaris were creamy white in color and somewhat transparent.
Look at Exercise 7 photos of Staph. aureus, M. luteus and E. coli for a reminder.

Sample Solution

ACED ESSAYS