Evolution 6-Antibiotic Resistance

Question 1

What is there trillions of?

Answer 1

There are trillions of tiny bacteria around us.

Question 2

What were some of the first life forms to appear on Earth?

Answer 2

Microorganisms called bacteria.

Question 3

What has a total biomass greater than that of all plants and animals combined?

Answer 3

Though bacteria consist of only a single cell, their total biomass is greater than that of all plants and animals combined.

Question 4

Where do bacteria live?

Answer 4

Virtually everywhere-On the ground, in the water, on your kitchen table, on your skin, even inside you.

Question 5

Generally, are bacteria good or bad? (2 points)

Answer 5

-Many bacteria are harmless or even beneficial, helping digestion and immunity.
- But there are a few bad ones that can cause harmful infections.

Question 6

What is designed to fight bacterial infections? What do they do? (3 points)

Answer 6

• Fortunately, there are amazing medicines designed to fight bacterial infections.
• Synthesized from chemicals or occurring naturally in things like mold, these antibiotics kill or neutralize bacteria by interrupting cell wall synthesis or interfering with vital processes like protein synthesis, all while leaving human cells unharmed.
• The deployment of antibiotics over the course of the 20th century has rendered many previously dangerous diseases easily treatable.

Question 7

In today’s time? What is happening?

Answer 7

More and more of our antibiotics are becoming less effective.

Question 8

What made antibiotics stop working? (4 points)

Answer 8

-The bacteria they were made to fight; the reason lies in Darwin’s theory of natural selection.
- Just like any other organism, individual bacteria can undergo random mutations.
- Many of these mutations are harmless or useless, but every now and then, one comes along that gives its organism an edge in survival.
- And for a bacterium, a mutation making it resistant to a certain antibiotic gives quite the edge.

Question 9

What happens as non-resistant bacteria are killed off? (6 points)

Answer 9

-Happens especially quickly in antibiotic-rich environments, like hospitals.
- There is more room and resources for the resistant ones to thrive, passing along only the mutated genes that help them do so.
- Reproduction isn’t the only way to do this.
- Some can release their DNA upon death to be picked up by other bacteria.
-Others use a method called conjugation, connecting through pili to share their genes.
- Over time, the resistant genes proliferate, creating entire strains of resistant super bacteria.

Question 10

How much time do we have before bacteria take over? (2 points)

Answer 10

• Well, in some bacteria, it’s already happened.
• For instance, some strands of staphylococcus aureus, which causes everything from skin infections to pneumonia and sepsis, have developed into MRSA, becoming resistant to beta-lactam antibiotics, like penicillin, methicillin, and oxacillin.

Question 11

What does MRSA do? (2 points)

Answer 11

• Thanks to a gene that replaces the protein beta-lactams normally target and bind to, MRSA can keep making its cell walls unimpeded.
• Other super bacteria, like salmonella, even sometimes produce enzymes like beta-lactams that break down antibiotic attackers before they can do any damage, and E. coli, a diverse group of bacteria that contains strains that cause diarrhea and kidney failure, can prevent the function of antibiotics, like quinolones, by actively booting any invaders that manage to enter the cell.

Question 12

Is there any good news? (3 points)

Answer 12

• There is good news.
• Scientists are working to stay one step ahead of the bacteria, and although development of new antibiotics has slowed in recent years, the World Health Organization (WHO) has made it a priority to develop novel treatments.
• Other scientists are investigating alternate solutions, such as phage therapy or using vaccines to prevent infections.

Question 13

What is the most important thing we can do to prevent antibiotic resistance from happening? (5 points)

Answer 13

• Curb the excessive and unnecessary use of antibiotics, such as for minor infections that can resolve on their own
• And Changing medical practice to prevent hospital infections can have a major impact
  -By keeping more non-resistant bacteria alive as competition for resistant strains.
• In the war against super bacteria, de-escalation may sometimes work better than an evolutionary arms race.

Question 14

What do antibiotics do? (3 points)

Answer 14

• Behind the scenes, they enable much of modern medicine.
• We use them to cure infectious diseases, but also to safely facilitate everything from surgery to chemotherapy to organ transplants.
• Without antibiotics, even routine medical procedures can lead to life-threatening infections.

Question 15

What are we at risk of?

Answer 15

Losing antibiotics.

Question 16

Why are we at risk of losing antibiotics? (2 points)

Answer 16

• Antibiotics are chemicals that prevent the growth of bacteria.
• Unfortunately, some bacteria have become resistant to all currently available antibiotics.

Question 17

At the same time, what have we stopped doing?

Answer 17

Discovering new antibiotics.

Question 18

Is there hope that we can get out of the problem?

Answer 18

Still, there’s hope that we can get ahead of the problem.

Question 19

What was the first widely-used antibiotic?

Answer 19

Penicillin, discovered in 1928 by Alexander Fleming.

Question 20

In his 1945 Nobel Prize acceptance speech, what did Fleming warn would happen? Was he right or wrong? (2 points)

Answer 20

• Fleming warned that bacterial resistance had the potential to ruin the miracle of antibiotics.
• He was right: in the 1940s and 50s, resistant bacteria already began to appear.

Question 21

From then until the 1980s, what happened? (4 points)

Answer 21

• Pharmaceutical companies countered the problem of resistance by discovering many new antibiotics.
• At first this was a highly successful-and highly profitable-enterprise.
• Over time, a couple things changed.
• Newly discovered antibiotics were often only effective for a narrow spectrum of infections, whereas the first ones had been broadly applicable.

Question 22

Why is this not a problem? (3 points)

Answer 22

• This isn’t a problem in itself, but it does mean that fewer doses of these drugs could be sold, making them less profitable.
• In the early days, antibiotics were heavily overprescribed, including for viral infections they had no effect on.
• Scrutiny around prescriptions increased, which is good, but also lowered sales.

Question 23

At the same time, what was happening? (2 points)

Answer 23

• At the same time, companies began to develop more drugs that are taken over a patient’s lifetime, like blood pressure and cholesterol medications, and later, antidepressants and anti-anxiety medications.
• Because they are taken indefinitely, these drugs are more profitable.

Question 24

By the mid-1980s, what was discovered? (2 points)

Answer 24

• No new chemical classes of antibiotics were discovered.
• But bacteria continued to acquire resistance and pass it along by sharing genetic information between individual bacteria and even across species.

Question 25

Now, what is happening?

Answer 25

Now bacteria that are resistant to many antibiotics are common, and increasingly some strains are resistant to all our current drugs.

Question 26

What can we do about bacteria becoming more resistant? (4 points)

Answer 26

-Control the use of existing antibiotics
-Create new ones
-Combat resistance to new and existing drugs
-Find new ways to fight bacterial infections.

Question 27

Who is the largest consumer of antibiotics? (2 points)

Answer 27

• Agriculture
• Uses antibiotics not only to treat infections, but to promote the growth of food animals.

Question 28

What does using large volumes of antibiotics do? (2 points)

Answer 28

• It increases the bacteria’s exposure to the antibiotics.
• Therefore their opportunity to develop resistance.

Question 29

What can many bacteria that are common in animals, do? (4 points)

Answer 29

• Many bacteria that are common in animals, like salmonella,
• Can also infect humans.
• Drug-resistant versions can pass to us through the food chain
• And spread through international trade and travel networks.

Question 30

In terms of finding new antibiotics, what offers the most promising new compounds? (2 points)

Answer 30

• In terms of finding new antibiotics, nature offers the most promising new compounds.
• Organisms like other microbes and fungi have evolved over millions of years to live in competitive environments, meaning they often contain antibiotic compounds to give them a survival advantage over certain bacteria.

Question 31

What can we also do?

Answer 31

Package antibiotics with molecules that inhibit resistance.

Question 32

What is one way that bacteria develop resistance? What would packaging the antibiotic with molecules that inhibit resistance do? (2 points)

Answer 32

• Proteins of their own that degrade the drug.
• By packaging the antibiotic with molecules that block the degraders, the antibiotic can do its job.

Question 33

What are two other possible ways that we can combat bacterial infections? (2 points)

Answer 33

• Phages, viruses that attack bacteria but don’t affect humans, are one promising new avenue to combat bacterial infections.
• Developing vaccines for common infections, meanwhile, can help prevent disease in the first place.

Question 34

What is the biggest approach to all of these different ways?

Answer 34

Funding, which is woefully inadequate across the globe.

Question 35

Why have many large pharmaceutical companies stopped trying to develop antibiotics?

Answer 35

• Antibiotics are so unprofitable.

Question 36

What happens when smaller companies bring new antibiotics to market? (2 points)

Answer 36

• Smaller companies that successfully bring new antibiotics to market often still go bankrupt,
• Like the American start up Achaogen.

Question 37

What fundamental problem do new therapeutic techniques like phages and vaccines face?

Answer 37

New therapeutic techniques like phages and vaccines, face the same fundamental problem as traditional antibiotics: If they’re working well, they’re used just once, which makes it difficult to make money.

Question 38

What can we do to successfully counteract resistance in the long term? What is one possible solution to this? (2 points)

Answer 38

• To successfully counteract resistance in the long term, we’ll need to use new antibiotics sparingly, lowering the profits for their creators even further.
• One possible solution is to shift profits away from the volume of antibiotics sold.

Question 39

What country is testing a new model? What does this model involve? (2 points)

Answer 39

-The United Kingdom is testing a new model.
-Healthcare providers purchase antibiotic subscriptions.

Question 40

While governments are looking for ways to incentivize antibiotic development, what are these programs still in?

Answer 40

The early stages.

Question 41

What will countries around the world need to do? We can still get ahead of antibiotic resistance with what?

Answer 41

Countries around the world will need to do much more, but with enough investment in antibiotic development and controlled use of our current drugs, we can still get ahead of resistance.

Question 42

What is the world full of?

Answer 42

Accidental inventions that have had major impacts on our lives.

Question 43

What was the first antibiotic invented by?

Answer 43

Accident.

Question 44

What is a zone of inhibition?

Answer 44

A zone of inhibition is the area around an antibiotic disk where bacteria (microbes) can’t grow.

Question 45

What do zones of inhibition tell you?

Answer 45

How effective an antibiotic is at killing microbes.

Question 46

The bigger the zone of inhibition, the more effective it is at what?

Answer 46

The bigger the zone of inhibition, the more effective the antibiotic is in killing bacteria (microbes).

Question 47

The smaller the zone of inhibition, the less effective it is at what?

Answer 47

Killing bacteria (microbes).

Question 48

How do you know if an antibiotic is ineffective in killing bacteria (microbes)?

Answer 48

No zone of inhibition forms around a disk of that antibiotic when it is placed on a growth medium.

Question 49

Explain the “transformation” method of how bacteria get new antibiotic resistance genes.

Answer 49

Bacteria take up “free floating” genes that have been released from dead bacteria in their environment.

Question 50

Explain the “conjugation” method of how bacteria get new antibiotic resistance genes.

Answer 50

A simple mating process where antibiotic resistance genes can be transferred from one bacterium to another.

Question 51

Explain the “transduction” method of how bacteria get new antibiotic resistance genes.

Answer 51

Antibiotic resistance genes are transferred from one bacterium to another by a virus.

Question 52

What are extremely rare?

Answer 52

Mutations that create new antibiotic resistance genes.

Question 53

How can bacteria such as Salmonella bacteria become resistant to many different antibiotics?

Answer 53

All living things gain new traits through mutation, including antibiotic resistance.

Question 54

What is an example of how bacteria get introduced to these mutations? (5 points)

Answer 54

-Salmonella is a bacteria that is commonly found in the intestines of animals, including chickens.
-They live in a community with many other bacteria where they can interact, and in these communities, they can communicate and share information, like genes.
-Although they can interact, it is only by chance that they successfully share their genes, resulting in mutation.
-Some of these mutations can be nonsense, or they can assist the bacterium in gaining resistance to antibiotics or increase their fitness.
-So, in the case of Salmonella bacteria, there were enough exchanges between bacteria resulting in resistance.

Question 55

How do farmers prevent the spread of disease in chicken livestock by using different antibiotics? (4 points)

Answer 55

-To prevent respiratory disease in young chickens on his farm, farmers add an antibiotic called erythromycin to the water that chickens drink.
-When erythromycin is used, only bacteria that have erythromycin resistance genes will survive.
-To prevent intestinal disease in young chickens on the farm, farmers use chicken feed that contains an antibiotic called ciprofloxacin.
-When ciprofloxacin is used, only bacteria that have ciprofloxacin genes will survive.

Question 56

Even though we have treatments for bacterial infections, what can bacteria develop resistance to?

Answer 56

Although we have treatments for bacterial infections, bacteria can develop resistance to antibiotic treatment through genetic mutations. This can mean that the drug is no longer effective.

Question 57

What is animal manure often stored in?

Answer 57

Open pits called “manure lagoons.”

Question 58

Why does the environment of manure lagoons create an ideal environment for bacteria to grow? (6 points)

Answer 58

• Animals in large industrial farms produce large quantities of manure- liquid (urine) or solid (feces) wastes.
• These wastes contain many different kinds of bacteria and viruses.
  -Lagoons are ideal places for bacteria reproduction.
• As bacteria living in the manure reproduce, they are exposed to low levels of antibiotics from the feces of animals that were treated with antibiotics.
  -Bacteria are also surrounded by sources of antibiotic resistance genes, such as viruses, free-floating antibiotic resistance genes, and other types of bacteria that are antibiotic resistant.
  -Wastes from manure lagoons may be be used to fertilize fields or may be accidentally released into nearby water sources.

Question 59

What are some different ways that antibiotic-resistant can spread? (3 points)

Answer 59

-Antibiotic-resistant bacteria from humans can enter into waterways if not sterilized properly from water sanitation systems.
-Contaminated farm animal crops and manure can leak into the soil and water potentially leading to Salmonella infection.
-Antibiotic-resistant bacteria can infect humans when they ingest contaminated food and water.

Question 60

What are six ways that antibiotic resistant bacteria such as Salmonella can spread between humans, animals and the environment? (6 points)

Answer 60

1. Antibiotic-resistant bacteria from humans can enter waterways if they are not completely removed by waste sanitation systems.
2. Farm animal manure applied to fields spreads antibiotic-resistant bacteria to soil and water.
3. Crops can be contaminated by antibiotic-resistant bacteria in soil and water.
4. Foodborne transmission of antibiotic-resistant bacteria to humans is a common route the spread to humans.
5. Antibiotic-resistant bacteria enter humans when they drink contaminated water.
6. Contact with pets and wildlife can transmit antibiotic-resistant bacteria to humans.

Question 61

Coevolution Definition

Answer 61

• The process of reciprocal evolutionary change that occurs between pairs of species or among groups of species as they interact with one another.

Question 62

Why is Coevolution necessary? (3 points)

Answer 62

• Very important as it is the reciprocal adaptation among interacting organisms.
• One of the primary forces that organize biodiversity by linking the DNA instructions of interacting species.
• It is also one of the major forces creating biodiversity because diversifying coevolutionary selection can lead to the formation of new species.

Question 63

Is Antibiotic Resistance an example of evolution, or coevolution? (4 points)

Answer 63

• Antibiotics are widely used for both human health and food production.
• Exposure to the spread of antibiotic resistance in disease-causing bacteria is an example of evolutionary adaptation by natural selection.
• It is also an example of a co-evolution challenge related to maintaining development goals.
• Bacteria can become resistant to antibiotics through mutations that alter the cellular targets of antibiotics or by acquiring targeted resistance genes from other bacteria.

Question 64

How does antibiotic resistance occur? (2 points)

Answer 64

• Antibiotic resistance happens when bacteria develop the ability to defeat the drugs designed to kill them.
• That means the bacteria are not killed and continue to grow.

Question 65

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