Lab for Exam 1

Question 1

Steps on Kirby-Bauer Method

Answer 1

1) Use a swab to create a lawn of the bacterial specimen to be tested onto the surface of a Mueller-Hinton agar plate

2) Place antibiotic discs onto the surface of the inoculated plate

3) After incubation measure the zones of inhibition of each antibiotic

4) Compare zones to interpretive table to determine susceptibility and resistance to each antibiotic

Question 2

What is the purpose of the LB agar plate?

Answer 2

It is a non-selective medium for bacterial growth

Question 3

What is the purpose of the LB/amp agar plate?

Answer 3

It is a selective medium containing an antibiotic to inhibit the growth of non-resistance cells

Question 4

What is the purpose of the LB/amp/ara agar plate?

Answer 4

It is a selective medium with an antibiotic which prevents growth of non-resistance cells and a sugar that allows for the expression of a plasmid gene

Question 5

Match the inoculated agar plates with their expected growth after incubation

+pGLO on LB/amp
+pGLO on LB/amp/ara
-pGLO on LB/amp
-pGLO on LB

Answer 5

+pGLO on LB/amp: White bacterial colonies

+pGLO on LB/amp/ara: Green fluorescent bacterial colonies

-pGLO on LB/amp: No growth

-pGLO on LB: Very dense white bacterial colonies