Mannitol salt agar (MSA) only allows the growth of halophiles (salt-loving microbes). Among the halophiles, mannitol fermenters
release acid that turns the pH indicator yellow; mannitol nonfermenters leave the medium red. Onto MSA you inoculate a halophilic mannitol nonfermenter and a nonhalophilic mannitol nonfermenter. Here the medium acts as a __________ medium. A. selective
B. differential
C. selective and differential
D. enrichment
The culture medium is a chemical preparation that has the necessary nutrients for microorganisms of a given biological sample to multiply, allowing its study, identification and analysis. The main components of a culture medium are sources of carbon, energy (sugars), nitrogen, phosphorus and minerals.
There are several types of culture medium, among them we can mention the differential culture medium, which is the type of medium that is being used in the experiment shown in the question above. The differential culture medium allows the distinction between various genera and species of similar microorganisms. This distinction is possible because this type of culture medium has substances that allow for a presumptive differentiation, evidenced by the color change or the morphology of the colonies.
