““The World We Create”The World We Create”NATS 101NATS 101Section 6Section 6

Project 4!

Due Tuesday May 4th

Final Exam!

Week April 27-29!

UNIT 4:A world of drugs, a blessing or a curse?

Antibiotics

• Explain what antibiotics are and how they work;

• Make decisions about when to take antibiotics;

• Diagram the process of bacterial resistance;

• Understand the consequences of bacterial resistance.

Expected Learning Outcomes:

Case Scenario #1

You tell her:– A. “You need to get to a doctor! They

will give you some antibiotics to make you feel better.”

– B. “You should take some Tylenol to make the pain go away.”

– C. “You should just rest and try using some throat spray or cough syrup. Make sure you have good soft tissues.”

Sore Throat!

Runny nose!Coughing up phlegm!

Ugh!

Headache!

– A. “I need to get to a doctor! They will give me antibiotics that will make me feel better.”

– B. “When I get home, I will try taking some Tylenol to make the pain go away.”

– C. “It’s probably nothing. Maybe I’m just nervous that Vicente will give us a pop quiz. I’m sure it will go away soon.”

Case Scenario #2I have to go! I can’t go!

It burns!My urine is cloudy!?

A. “First thing in the morning, I am getting myself into the doctor. They will give me some antibiotics to make me feel better.”

B. “I should take some Tylenol.” C. “It’s probably nothing. Maybe I am over-worked from

being so busy yesterday. I’m sure it will go away soon.”

Case Scenario #3

Headache!

Fever!

Vomiting!

Muscle Aches!

What did you decide?

Scenario 2

Antibiotics, Tylenol, Take no action

Scenario 3

Antibiotics, Tylenol, Take no action

Scenario 1

Antibiotics, Tylenol, Cough Syrup/Throat Spray

Would I Take Antibiotics For…?Urinary Tract Infection

Bladder Infection

Common Cold

Flu

Herpes

Broken armDog Bite

Strep ThroatYeast Infection

Pneumonia

Pink Eye

• When do doctors prescribe antibiotics?

• What instructions are given when antibiotics are prescribed?

• How important are these instructions? Do we need to follow all of them?

What do antibiotics do?

- Antimicrobial drugs can work against protozoa, bacteria or fungus.

- Antibiotics specifically work against bacteria.

**They don’t stop viruses** X

How do Antibiotics work? Different Mechanisms:

- Weaken the cell wall, causing cells to lyse;- Block DNA transcription; - Stop protein synthesis so the cell can’t make essential components such as flagella- Enhance immune system

Bacteria or Virus?

Would an antibiotic work?

Urinary Tract Infection Bladder Infection

Common Cold Flu Herpes

Broken armDog Bite Strep ThroatYeast Infection

Pneumonia

Pink Eye

Bacteria Virus

Why do we have to be careful?- Why do Doctors tell us we MUST TAKE ALL of our prescribed antibiotics?

- What are the consequences of not doing this?

Let’s See What Happens… We are going to pretend that we are all different types

of bacteria! If you are a blue, green, or yellow bacteria, you are

considered a “good” bacteria; red is considered a “bad” bacteria.

Each row represents a new day in the life of our host body.Each new day, we are analyzing a sample of the total bacteria present in our host body.

Day 1

Day 2

Day 3

Day 4

Day 5

Day 6

Day 7

Day 8

Day 9

Day 10

Day 11

Day 12

Day 13

Day 14

So, What Happened?

What did you observe?(What happened to the good bacteria?

The bad bacteria? At the end of treatment?)HOW CAN THIS BE EXPLAINED?

Is this bad? Why?

Why do we have to be careful?When taking antibiotics…

- “Feeling better” does not necessarily mean that all of the harmful bacteria is gone.

- There is a vast amount of variation within bacteria populations.

- Individual bacterium have different levels of resistance to certain antibiotics.

- As a result, some bacteria can withstand a higher concentration of antibiotics.

Why do we have to be careful? Antibiotic Resistance: The ability of bacteria to resist

or overcome the effects of an antibiotic.

Within a species, bacteria can be grouped based on their variable resistance. These are called strains.

Antibiotic resistance arises through the process natural selection.

Natural Selection

Some variations give certain individuals a better chance of survival and/or a higher reproduction rate under certain “environmental pressures.”

Individuals in a population are variable

Natural SelectionThese variations are heritable, meaning they get

passed on to any offspring the individual has.

Those individuals with a variation that let them survive better and

produce more offspring will represent a higher proportion of the final population than they did in the

original population.

Antibiotic Resistance

21 3

1 Antibiotic kills susceptible bacteria in population;

2 Resistant strains survive;3 Less competition = easier life = lots of

reproduction = higher percentage ofresistant strains in final population.

Resistance: A Growing ProblemBacteria divide very rapidly

-Once every 20 minutes! If you start with a single resistant bacteria… 1 hour 6 hours 12 hours 24 hours

8 262144 6.871 x1010 4.722 x 1021

Resistance can spread through a population very quickly!

Why is this a problem?This speeds up the process of natural selection and evolution through mutation!

Resistance: A Growing Problem

1967: “It is time to close the book on infectious diseases. The war against pestilence is over.”

1998: “Infectious Diseases a Rising Peril – Death Rates up 58% in US since 1980”

2002: World data from the CDC reports respiratory infections (influenza, pneumonia) as the #4 cause of death

That’s 3.9 million people!

Resistance: A Growing Problem

The useful lifespan of an antibiotic is

limited due to the increasing prevalence of

resistance.

MRSACDC estimated that 94,360 invasive MRSA infections occurred in the United States in 2005; 18,650 of these were associated with death.

How we’re contributing to the problem

So why has resistance risen so dramatically in the past 20 years?

What are the potential consequences (social, economical) of this problem?

Over-prescription of antibiotics; Overuse of antibiotics in animal feed; Scarce research and development in the field of antibiotic pharmaceuticals; Advances in medicine & society.

Causes?

What Are the Consequences?

More Infection

New Treatments

New Drugs Stronger Drugs

Unknown Consequences $$$ Worse Side Effects

Bacterial Resistance

More Carriers

Why All These Rules?• Take only those antibiotics that are prescribed for you—don't

take someone else's antibiotics, or antibiotics that you find around the house.

• Don’t ask for a stronger antibiotic.• When a doctor prescribes an antibiotic for you, take all of it

as directed.• When you’re sick, rest. Don’t go back to your normal routine

just because you think the antibiotic will handle the problem.

In your groups, determine the rationale behind each of the guidelines given with a prescription for antibiotics. Why do doctors tell you these things?

You have 5 minutes