ASSIGNMENT
Day 1.
Choose an “Unknown Culture” and do the following:
1. Write down the number of your unknown on a fresh page in your notebook.
2. Prepare a smear and do a Gram Stain
a. Write the results of the Gram stain under your unknown number in your notebook and take a picture.
b. Show the instructor your Gram Stain at 1000x magnification.
3. Inoculate the following plates for isolation:
a. Blood Agar Plate (BA)
b. Mac Conkey Agar Plate (MAC)
c. PEA Agar Plate
d. Nutrient Agar Plate
e. Mannitol Salt Agar Plate (MS)
Day 2.
Observation of Cultures:
1. Describe the colonies seen on
a. Blood Agar Plate
b. Mac Conkey Agar Plate
c. PEA Agar Plate
d. Nutrient Agar
e. Mannitol Salt Agar Plate
2. For organisms growing on a Mac Conkey Agar Plate, after describing the colonies, circle one isolated colony and inoculate the following media:
a. TSI Agar Slant – remember to stab the medium first then inoculate the slant
b. SIM medium – remember this is semisolid and is inoculated by stabbing the medium only
c. Simmon’s Citrate medium – inoculate the slant only
d. MR/VP broth
e. Urea broth
f. Nitrate Broth
3. For organisms growing on PEA agar plate, after describing the colonies, choose an isolated colony and do the following:
a. Inoculate a Bile Esculin Agar Slant – slant only
b. Inoculate Phenol Red Broth with Glucose
c. Do a catalase test – remember to choose isolated colonies (take a picture)
d. Do an oxidase test – choose cells from an isolated colony (take a picture)
4. Take a picture of each plate.
Day 3.
a. Prepare two charts (handwritten or printed) – one for recording the results from the Mac Conkey Agar Plate and one to record the results from the PEA Agar Plate: You are required to make notes on the chart on what and how much reagents you are going to add to the appropriate media.
b. Add all the reagents first. Once you record the results, line up the tubes you inoculated from the Mac Conkey Agar plate and take a picture of it – make sure you line up the tube so that your unknown number and the color change, if any, are clearly seen
c. Take pictures of PEA plate test results for bile esculin agar, and phenol red broth
