A. Compare enriched complex, and synthetic (defined) media.
Enriched media - These media contain elements necessary for the growth of as many microbes as possible including the fastidious species of microbe. It contains animal tissue. It is used to grow all types of bacteria present in a specimen. The MRS medium an enriched medium that facilitates Lactobacillus acidophilus growth. A synthetic (defined) medium is a chemically defined media with all chemicals present known and contain no plant-animal tissue. It is used to grow specific types of microbes. Complex media is a chemically undefined media. It contains amino acids and sugar and other ingredients not exactly known, it targets the growth of specific types of bacteria. Mannitol Salt Agar is used for the isolation and identification of Staphylococcus. It is a complex medium since it contains ...view middle of the document...
Selective media allow certain types of organisms to grow, and inhibit the growth of other organisms. This is done in several ways. For example, microbes that can utilize a given sugar are easily noticed by making that sugar the available in the medium as the only food. (Gladwin, & Trattler, 2011).
C. Explain why it is necessary to use solid media to obtain a pure culture.
Solid media is used to obtain a pure culture because the pure growth of bacteria takes place at the thin ends of inoculation streak. This is not possible with liquid media. This is necessary because we need to be able to separate out individual cells of a particular microbe. The solid media provides a surface for the individual cells that become separated and isolated from the other microbial cells that could possibly be present in the original sample. The solid media has all the required nutrients as the broth media, but agar which is a solidifying agent, is added to the mixture. Agar is stronger than gelatin and will not be eaten by the bacteria. We can melt the agar so we can work with it easily until it cools off at a certain temperature. A petri dish is an example of a solid media (Gladwin, & Trattler, 2011).
D. Compare your results using the streak-plate and pour-plate methods of isolation
In streak plate method, it is easier to isolate individual colonies because different colonies proliferate independently along the streaks. In pour plate methods, colonies are concentrated within the same region making it difficult to isolate individual colonies.
E. Describe the size, shape, color and growth pattern of the colonies that grew from your S. epidermidis. S. epidermidis colonies are 1 to 2 mm in length that is white in color and slightly raised. The bacteria cells are arranged in clusters (Staphylococci).
Gladwin, M., & Trattler, B. (2011). Clinical Microbiology made ridiculously simple
Ramakrishnan, S., & Sulochana, K. N. (2012). Sankara Nethraylaya's manual of medical laboratory techniques. New Dehli, India: Jaypee Brothers Medical Publishers.