Selective Media

Mannitol salt agar is selective for ____________

• Gram positive bacteria

• Gram negative bacteria

• salt tolerance

• growth in the presence of bile

If a microbe grows well on Hektoen Enteric agar and produces colonies and change the agar to orange, you can conclude __________

• the bacteria is most likely Gram positive and ferments lactose

• the bacteria is most likely Gram positive and does not ferment lactose

• the bacteria is most likely Gram negative and ferments lactose

• the bacteria is most likely Gram positive and does not ferment lactose

In Hektoen Enteric media, black color results from _______.

• the hydrolysis of esculin

• the fermentation of sucrose

• the reduction of sulfur

• the oxidation of iron

If you want to select for a specific type of bacteria, what type of media would you use?

• Selective media

• Differential media

• Nutrient broth

• autoclave

The type of culture media that can turn bacteria different colors on a petri dish is called a ____ media

• selective

• natural

• differential

• broth

Regardless of the media type, the best temperature for most bacteria is

• 10 -15^o C

• 60^oC

• 25 - 40^oC

• 100^oC

MacConkey's agar will only grow bacteria that are...

• Gram-positive

• Gram-negative

• halophilic

• bacilli

If pink colonies grow on MacConkey agar, the bacteria are

• Gram positive and lactose fermenter

• Gram negative and lactose fermenter

• Gram positive and non-lactose fermenter

• Gram negative and non-lactose fermenter

If Mannitol Salt agar is growing bacteria, and the medium itself appears bright yellow, which species of bacteria is growing?

• Staphylococcus epidermis

• Staphylococcus aureus

• Escherichia coli

• Streptococcus pyogenes

If MacConkey's agar shows bacterial growth in colorless colonies, what can you know about the bacteria growing?

• Gram-positive lactose fermenter

• Gram-negative lactose fermenter

• Gram-positive non-lactose fermenter

• Gram-negative non-lactose fermenter