Midterm: Selective Differential Media

Question 1

What type of microbe is a MSA designed to cultur?

Answer 1

Staphylococci

Question 2

What species is MSA designed to differentiate?

Answer 2

Staphylococcus aureus

Question 3

What is the selective agent of MSA?

Answer 3

High salt concentration

Question 4

What type of microbe is EMB Agar designed to culture?

Answer 4

Gram- negative bacteria

Question 5

What are the selective agents of EMB agar?

Answer 5

Eosin Y and methylene blue

Question 6

What are the differential agents of EMB Agar?

Answer 6

Lactose, eosin Y, methylene blue

Question 7

How is MacConkey Agar similar to EMB media?

Answer 7

They both are selective for gram-negative bacteria and differentiate based on lactose fermentation

Question 8

What type of microbe is PEA designed to culture?

Answer 8

Gram-positives

Question 9

When would PEA be used in a clinical setting?

Answer 9

Preventing the growth of common contaminants such as E. coló and Proteus species, commonly found alongside the staph and strep species from clinical specimens.

Question 10

What is the selective agent in PEA?

Answer 10

Phenylethyl alcohol

Question 11

How do fungi and bacteria look distinctively different when grown on a Petri dish?

Answer 11

Fungus looks fuzzy and bacteria look mucoid