lab 4 Flashcards
selective media
will inhibit the growth of different bacteria to allow for one specific type to grow
differential media
will allow growth of multiple types of bacteria, but they will look different on a plate
what is an example of both selective and differential
Mannitol Salt Agar
How is Mannitol Salt Agar selective ?
due to high salt concentration (7.5-10%) and used for the ISOLATION of gram + bacteria, pathogenic Staphylococci and non pathogenic Staphylococci. PREVENTS GROWTH OF GRAM -
How is Mannitol Salt Agar differential ?
it contains mannitol that can be fermented and PHENOL RED.
What color indicates fermentation ?
acidic and yellow
What is a sign of no fermentation ?
red color
How is MacConkey Agar selective ?
Bile salts isolate gram (-) bacteria by inhibiting gram (+) bacteria.
How is MacConkey Agar differential?
Lactose is used to differentiate bacteria based on their ability to ferment
In MacConkey Agar, what color indicates fermentation of lactose ?
pink
What color is it when fermentation does not occur ?
pale color
How is Vogel Johnson Agar selective ?
Selective for gram (+) by use of LiCl, tellurite, and glycine content
How is Vogel Johnson Agar differential?
Contains mannitol and phenol red indicator for differentiation (just like the
mannitol salt agar)
In Vogel Johnson Agar, which color indicates fermentation?
yellow
What can bacteria do differently in Vogel Johnson Agar>
Bacteria can reduce tellurite to tellurium = black
