Part 3: How do bacteria become resistant to multiple antibiotics?

Scroll down to read through the comic, complete all activities, and answer Questions 9-15 before clicking "Next Page"

The Story:

Cartoon Summary

Ajay knows that mutations could cause new traits to appear. However, he also knows that mutations are rare and random events. He asked his biology teacher “How could Salmonella bacteria become resistant to many different antibiotics?”

You and your classmates will model how Salmonella living in the intestines of a chicken may acquire antibiotic resistance genes from other bacteria around it.

The intestines of a chicken are crowded with millions of bacteria that may contain different antibiotic resistance genes—genes that enable them to survive exposure to specific antibiotics.

Activity: Mutation Roulette

Part 1: Press and hold the arrow above the color wheel to make the wheel spin. To make the wheel stop, let go of arrow. Whatever color you land on is the resistance gene you have acquired! Perform this 4 times. Keep track of the colors you get in your lab notebook!

Notice how mutations are acquired through random events.

Color Wheel

Key for Color Wheel

Yellow = No Mutation.

Blue = Tetracycline Resistance Gene

Black= Erythromycin Resistance Gene

Green = Ciprofloxacin Resistance Gene

Pink = Penicillin Resistance Gene

Red = Cephalosporin Resistance Gene

CLICK HERE to read Question 9a.

What color(s) did you get on the color wheel?

(Record all attempts in your Digital Lab Notebook)

Part 2: Roll the dice by clicking (computer) or tapping (phone/tablet) on the dice. Perform this 4 times.

Use the Key for Dice Roll below. If you rolled a 1 or 6, you did not get a mutation. If you roll a 2, 3, 4, or 5, you got a mutation! Keep track of the numbers you get in your lab notebook!

Read about the method that the mutation was acquired. Notice how mutations are acquired through random events.

Dice (Die)

Key for Beads

Blue = Tetracycline Resistance Gene

Black= Erythromycin Resistance Gene

Green = Ciprofloxacin Resistance Gene

Pink = Penicillin Resistance Gene

Red = Cephalosporin Resistance Gene

CLICK HERE to read Question 9b.

What number(s) did you roll?

(Record all attempts in your Digital Lab Notebook)

Using the mutations you identified in Part 1 and Part 2, drag and drop the resistance genes you got into your Simulated Salmonella bacteria cell. Each colored bead represents a resistance gene mutation.

Simulated Salmonella Bacteria Cell

in Chicken Intestine

Click Steps 1-4 and read questions below. Record answers in your Digital Lab Notebook.

Steps 1-4

You will use either dice rolls or a color wheel along with beads to model how bacteria can become resistant to multiple antibiotics. To identify the resistance genes you can roll dice and follow the steps below or spin the color wheel with the Key for Color Wheel to make a model of your own to show the randomness of having a resistant gene. The Simulated Salmonella Bacterial Cell in Chicken Intestines contains beads that represent antibiotic resistance genes from other bacteria that live in the chicken’s intestines.

Step: 1

Roll the dice. Follow the instructions on the Key for Dice Roll to determine what happens to the Salmonella bacteria. Did the Salmonella bacteria get a new antibiotic resistance gene, if so, what resistance gene did the Salmonella receive?

NO - Go to Step 2

YES - Answer the next two bullets:

• On the Key for Beads above, identify the name of the antibiotic resistance gene that is now present in your model bacteria.

• What process was used to acquire this resistance gene? Describe the process by which the bacteria obtained the new gene.

Step 2:

Roll the dice again. Follow the instructions on the Key for Dice Roll to determine what happens to the Salmonella bacteria. Did the Salmonella bacteria get a new antibiotic resistance gene, if so what resistance gene did the Salmonella receive?

NO - Go to Step 3.

YES - Answer the next two bullets:

• On the Key for Beads, identify the name of the antibiotic resistance gene that is now present in your model bacteria.

• What process was used to acquire this resistance gene? Describe the process by which the bacteria obtained the new gene.

Step 3:

NO - Go to Step 4

YES - Answer the next two bullets:

• On the Key for Beads, identify the name of the antibiotic resistance gene that is now present in your model bacteria.

• What process was used to acquire this resistance gene? Describe the process by which the bacteria obtained the new gene.

Step 4:

NO - Go to Question 9

YES - Answer the next three bullets:

• On the Key for Beads, identify the name of the antibiotic resistance gene that is now present in your model bacteria.

• What process was used to acquire this resistance gene? Describe the process by which the bacteria obtained the new gene.

• How many attempts did it take to become multi-drug resistance? What is it resistant to?

Question 9

Multidrug-resistant bacteria are resistant to more than one antibiotic. Is your Salmonella bacteria model multidrug-resistant? If so, list the antibiotics that it is resistant to.

Question 10

If a person becomes infected with Salmonella bacteria like the one that you modelled, what kinds of antibiotics would be effective for treating the infection? Explain how you can tell.

Question 11

If you are working with other students who have made Salmonella bacteria models, explain how you would identify the Salmonella bacteria model that would be most likely to survive and reproduce in an environment where multiple antibiotics are present.

Question 12

Ajay wanted to know how Salmonella bacteria could become resistant to many different antibiotics. Explain how it is possible for bacteria to acquire resistance to multiple antibiotics without relying on the rare and random process of mutations.