Question: Is MSA Selective Or Differential?

How is MSA selective and differential?

Mannitol Salt Agar (MSA) is a selective and differential medium.

The high concentration of salt (7.5%) selects for members of the genus Staphylococcus, since they can tolerate high saline levels.

Organisms from other genera may grow, but they typically grow very weakly..

Is pea selective or differential?

Phenylethyl alcohol agar (PEA) is a selective medium used to cultivate Gram positive organisms. The active ingredient, phenylethyl alcohol, inhibits or markedly reduces growth of Gram negative organisms by interfering with DNA synthesis. PEA also prevents Proteus species from swarming across the surface of the agar.

Does E coli grow on MSA?

(A) Staphylococcus aureus, (B) Staphylococcus epidermidis, and (C) Escherichia coli streaked on a mannitol salt agar plate. … The growth of E. coli was inhibited by the high salt concentration.

What Bacteria grows on MSA?

Staphylococcus aureus and Staphylococcus epidermidis on mannitol salt agar. Mannitol salt agar is a commonly used growth medium in microbiology. It encourages the growth of a group of certain bacteria while inhibiting the growth of others.

What does a red color symbolize in a MSA plate?

Bacteria growing on mannitol salt agar are positive for mannitol fermentation if the culture medium under their colonies is changed from its normal red color to yellow, indicating acidic growth products. Bacteria unable to use mannitol usually change the medium to a magenta color in the vicinity of growth.

What substance makes MSA differential Why?

The substance that makes MSA differential is mannitol, because it can be effectively fermented by Staphylococcus aureus, but not other Staphylococcus species.

How is MSA a differential media?

Mannitol salt agar or MSA is a commonly used selective and differential growth medium in microbiology. It encourages the growth of a group of certain bacteria while inhibiting the growth of others. … If an organism can ferment mannitol, an acidic byproduct is formed that causes the phenol red in the agar to turn yellow.

Is TSA selective or differential?

TSA (Trypticase Soy Agar) and NA (Nutrient Agar) are General Purpose Media that are not selective or differential, their purpose is simply to grow many types of bacteria cheaply. Here we will use a general purpose media to compare the growth on the selective and differential media.

Can a media be both selective and differential?

Selective and differential media can be combined and play an important role in the identification of bacteria by biochemical methods. Another commonly used medium that is both selective and differential is eosin-methylene blue (EMB) agar. … Therefore, EMB is selective for gram-negatives.