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Understanding antibiotic resistance
Understanding antibiotic resistance

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1.1 Using quorum sensing to treat infections

On its own, a single bacterium cannot cause an infection but, just like the bacteria in Activity 1, pathogenic bacteria use quorum sensing to coordinate their behaviour and attack together. Disrupting this coordinated response by blocking quorum sensing could help to treat infections, as you will see next.

Activity 2 Preventing infections by disrupting quorum sensing

Timing: Allow about 15 minutes

Watch part of the video in the following link in which Bonnie Bassler explains how quorum sensing antagonists (drugs that disrupt quorum sensing) can prevent infections by Vibrio cholerae.

Preventing infections by disrupting quorum sensing [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)] . Watch from 54:50 until 57:05.

Now answer the following questions, based on the video.

  1. What effect would a quorum-sensing antagonist have on bacteria?

a. 

a) It kills them


b. 

b) It blocks their ability to communicate with each other


c. 

c) It helps them to communicate with each other


d. 

d) It makes them grow faster


The correct answer is b.

Answer

The correct answer is (b) it blocks their ability to communicate with each other.

  1. What effect does the quorum-sensing antagonist have on the fluorescence of Vibrio fischeri bacteria?

a. 

a) It stops them fluorescing


b. 

b) It makes them fluoresce more


c. 

c) It does not have any effect


The correct answer is a.

Answer

The correct answer is (a) it stops them fluorescing.

  1. How many people die from Vibrio cholerae infections?

a. 

a) Less than 100 000 per year


b. 

b) 100 000 per week


c. 

c) Over 100 000 per year


The correct answer is c.

Answer

The correct answer is (c) over 100 000 people per year.

  1. What is the first step in a Vibrio cholerae infection?

a. 

a) Expression of a protein that causes the bacteria to fluoresce


b. 

b) Expression of a virulence protein that allows the bacteria to stick to the gut


c. 

c) Expression of a protein that makes the bacteria move faster


The correct answer is b.

Answer

The correct answer is (b) expression of a virulence protein that allows the bacteria to stick to the gut.

  1. How does blocking quorum sensing affect the expression of this protein and the Vibrio cholerae infection?

a. 

a) It increases protein expression and prevents the infection


b. 

b) It decreases protein expression and prevents the infection


c. 

c) It increases protein expression and increases the likelihood of infection


d. 

d) It decreases protein expression and increases the likelihood of infection


e. 

e) It has no effect on protein expression or infection


The correct answer is b.

Answer

The correct answer is (b) it decreases protein expression and prevents the infection.