Bacteria identification through functional media | Homework Help
Bacteria Identification through Functional Media
Exercise: Comparison of Functional Media
A. Why is Mannitol Salt Agar (MSA) classified as a type of both selective and differential medium?
MSA is a selective as well as a differential media.
Mannitol is the differential part, it indicates organisms that ferment mannitol. If mannitol fermentation is occurring, lactic acid will be produced, and the pH will drop causing the MSA plate to turn yellow. The salt portion is selective for halophiles; organisms that cannot withstand a high salt content will be unable to grow well.
B. Were there any samples that showed no growth? If so, list the samples and media. Given that microorganisms are everywhere, would you expect to see growth on every plate? Why or why not?
C. Which sampling site and plate produced the most growth overall? Describe why you believe the most growth occurred here.
D. Did you note any color changes on the MSA plate? (A color change is when the bacteria appear as a different color than the media.) What can be concluded from this observation?
E. Did you note any color changes on the MAC plate? What can be concluded from this observation?
F. Did you note any color changes on the EMB plate? What can be concluded from this observation?
G. Many areas of the body support normal flora. Identify two areas of the body where a physician might be concerned if they found bacteria.