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coppercattle386Lv1

6 Nov 2019

2,3,&4 please

2. List four possbe ources of contamination of culftures. 3. How does agar provide a solid culture medium for microbial growth? How might water on the surface of the agar cause a disruption of colony formation and growth? 4.
Show transcribed image text 2. List four possbe ources of contamination of culftures. 3. How does agar provide a solid culture medium for microbial growth? How might water on the surface of the agar cause a disruption of colony formation and growth? 4.

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Related questions

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

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. Decrease oxygen content

d. Bacteria from growing in wrong direction

e. Airborne contamination

If you see a yellow halo surrounding a colony on a MSA plate, which of the following is likely to be true?

Select one:

a. Glycolysis occurred

b. The organism is Staphylcoccus epidermidis

c. Colonies are not isolated

d. Fermentation occurred

e. Colony is Gram-negative

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

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.

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.

Considering the cultures to be used for inoculating each medium in this exercise, how many microbial types should you expect to see in/on each medium?

Select one:

a. 3

b. 0

c. 1

d. Several

e. 2

Which of the following is common to minimize airborne contamination?

Select one:

a. Make someone else do the experiment

b. Perform the experiment in a windy room

c. Keep a microscope nearby

d. Breathing in sample

e. Hold open tubes at an angle

How can a hot sterile flame loop be cooled quickly to use in the next streak?

Select one:

a. Put in sterile portion of agar plate

b. Blow on it

c. Stick the loop in ice

d. Set the loop on the lab bench

e. Pour tap water on the loop

True or false: Most colonies can been seen without aid (naked eye), and most single cells cannot be seen without a microscope.

Select one:

True

False

An isolated, single colony forms after incubation of a:

Select one:

a. Virus (viral particle arrangement in some cases)

b. Single cell (cell arrangement in some cases)

c. Sterile agar plate

d. Sterile flame loop

e. Liquid mixed culture

These are commonly used for growing stock cultures that can be refrigerated for several weeks:

Select one:

a. Broth tubes

b. Cotton swabs

c. Gym socks

d. Agar slants

e. Petri dishes

Beginning at the base of the slant surface and gently moving the loop back and forth as you withdraw is called:

Select one:

a. Slant mixing

b. Fishtail inoculation

c. Zig-zag streaking

d. Squirrel inoculation

e. Quadrant streaking

If you are going to mix a broth culture prior to transfer, what is a safe way to do this without special equipment?

Select one:

a. Tap the tube with your fingers

b. Vortex it

c. Use a inoculating loop

d. Stick the tube in the outer cone

What is the primary purpose of the streak plate method?

Select one:

a. Quantify CFUs

b. Isolate an individual colony

c. Quantify the cell count of a mixed culture

d. Inoculate a culture on a plate

e. Confirm the identity of an unknown genus

You are working in a food safety lab and were given some samples to evaluate for microbial contamination. The particular sample youâre working with today is a potato purchased at local farmerâs market booth. This farm does not use organic growth techniques. You swabbed the potato and performed a T-streak on MacConkey agar. From this you isolated several different colony morphologies, but one was of particular interest. The colonies were round and very glossy. On MacConkey agar they develop a reddish color.

You amplified one of these colonies for further analysis.

1. You prepare a wet mount and observe the microorganism under high magnification. You find that it has a rod shape and is non-motile.

2. You inoculate a thiolglycolate tube with this organism and incubate it overnight. Results are shown below.

Growth in Thiolglycolate (it is cloudy all the way to the bottom)

3. You inoculate a BD Enterotube with your unknown isolate. The results are shown below.

1 2 3 5 6 7 8 9 11 12

Glucose Lysine Ornithine Adonitol Lactose Arabinose Sorbitol V/P Urea Citrate

Color Yellow Purple Yellow orange yellow yellow yellow red pink blue

Gas? Yes

Note: I left out chambers 4 and 10 since you have no experience reading them and interpreting the results. The organism is negative for Indole, H2S, Dulcitol, and PA.

Case Study 4

Name: ____________________________________

Questions:

1. How would you classify this organism based on oxygen tolerance?

2. What is the scientific name of your microbe?

3. Describe the process you used to come to this result.

4. Is this a microbe that would be expected on produce?

5. Is this microbe a pathogen? Is it an opportunistic pathogen?