If you were to make Columbia CNA with 5% sheep blood agar plates with twice as much colistin, how would the results likely be affected?
Select one:
a. Less Gram-positive growth, more Gram-negative growth
b. Less Gram-positive growth, no or even less Gram-negative growth
c. More Gram-positive growth, more Gram-negative growth
d. More Gram-positive growth, no or even less Gram-negative growth
e. Same Gram-positive growth, no or even less Gram-negative growth
2. In Mannitol Salt Agar lab, you were told to invert the plate before incubation. This is a common practice to avoid:
Select one:
a. Condensation drops
b. Increased smell
c. Decreased oxygen content
d. Bacteria from growing in the wrong direction
e. Airborne contamination
3. If you see a yellow halo surrounding a colony on an MSA plate, which of the following is likely to be true?
Select one:
a. Glycolysis occurred
b. The organism is Staphylococcus epidermidis
c. Colonies are not isolated
d. Fermentation occurred
e. Colony is Gram-negative
4. Which one of the following is found in MSA plates, but not in NA plates?
Select one:
a. Phenol red
b. Agar
c. Tryptose
d. Peptone
e. Beef extract
5. Why are the three organisms of Phenylethyl Alcohol Agar lab inoculated on the same plate?
Select one:
a. To avoid contamination
b. For easy viewing purposes
c. To save resources
d. To avoid fluctuations in medium content and environmental effects
6. For which reason would you most likely use a PEA plate for culturing after taking a sample from a patient?
Select one:
a. To isolate Streptococcus and Staphylococcus from other fecal bacteria
b. To detect Escherichia contamination on the skin
c. To find E. coli strains associated with food poisoning
d. To identify gram-negative anaerobes in the patient's flora