Lesson video

Hello, I'm Mr. Marchant, and I'll be your history teacher for today's lesson.

I'm really excited to have you joining me as we explore today's subject, and my number one priority will be to help ensure that you can meet our lesson objective for today.

Welcome to today's lesson, which is part of our Edexcel unit on medicine in Britain and our AQA unit on health and the people.

By the end of today's lesson, you'll be able to evaluate the impact of antibiotics on modern medicine.

There are two keywords which will help us navigate our way through today's lesson.

Those are antibiotic and resistance.

An antibiotic is a medicine which destroys or limits the growth of bacteria in the body.

And resistance in this context refers to the ability to fight something or not be affected by it.

Today's lesson will be split into three parts, and we'll begin by focusing on magic bullets.

During the 19th century, the role microbes play in causing disease was revealed.

Scientists began to search for substances which could safely treat infections by attacking microbes in a body.

Magic bullets were the first successful treatments which could fight diseases and illnesses in this way.

Substances which can destroy or slow down the spread of harmful microbes in the body were known before the 20th century.

For instance, syphilis, a disease caused by bacterial infections, had been fought for centuries using chemicals such as mercury.

However, whilst mercury did attack harmful microbes, it was also toxic and poisoned the body.

Indeed, some patients died from mercury poisoning rather than because of the disease.

Nevertheless, many scientists remained convinced that chemical cures existed which could attack microbes without harming the body, including the German scientist Paul Ehrlich.

Ehrlich experimented with over 600 compounds of arsenic to test whether they could treat syphilis safely.

Whilst Ehrlich's experiments were unsuccessful, they were repeated in 1909 by a Japanese scientist, Sahachiro Hata.

This time, one of Ehrlich's arsenic compounds, named Salvarsan 606, proved successful, and it was found that it did not harm the body.

Because it was both effective and safe, Salvarsan 606 became known as a magic bullet and inspired further research to find other magic bullets.

A second magic bullet was discovered two decades later.

In 1932, the German scientist Gerhard Domagk found that a chemical known as prontosil could fight the bacteria responsible for some types of blood poisoning.

Indeed, Domagk even tested prontosil successfully on his own daughter.

Further research revealed that both Salvarsan 606 and prontosil contained sulfonamide, which allowed them to target and attack harmful microbes.

This knowledge was used to develop medicines which could cure other diseases caused by bacteria, such as pneumonia and scarlet fever.

In fact, British Prime Minister Winston Churchill was cured of pneumonia during World War II using one of these drugs.

So thinking about what we've just heard, what was the problem with mercury treatments for syphilis? Was it that it had no effect on the infection-causing bacteria, that mercury poisons the human body, or that the treatment was only available to royalty? Pause the video here, and press play when you're ready to see the right answer.

Okay, well done to everybody who said that the correct answer was B.

The problem with mercury treatments for syphilis was that mercury poisons the human body.

This even led to some patients suffering from syphilis dying of mercury poisoning rather than because of the disease.

And let's try another question.

What was the first magic bullet? Pause the video here, and press play when you're ready to see the right answer.

Okay, well done to everybody who said the correct answer was Salvarsan 606.

This was the first magic bullet.

And let's try another question.

This time we have a statement on the screen which reads: Salvarsan 606 and prontosil were considered magic bullets because they were very cheap treatments.

But is that statement true or false? Pause the video here, and press play when you're ready to see the right answer.

Okay, well done to everybody who said that that statement was false, but we need to be able to justify our response.

So why is it that that original statement was incorrect? Pause the video here, and press play when you're ready to check your answer.

Okay, well done to everybody who said Salvarsan 606 and prontosil were considered magic bullets because they were both safe and effective for curing some bacterial infections.

And so now we're in a good position to put all of our knowledge about magic bullets into practise.

I want you to describe one difference between the treatment of syphilis before and after 1900.

Your answer should include specific factual details from both periods.

So pause the video here, and press play when you are ready to reflect on your response.

Okay, well done for all of your hard work on that task.

So I asked you to describe one difference between the treatment of syphilis before and after 1900, and your answer may have included: one way in which the treatment of syphilis was different after 1900 was in the use of magic bullets.

The discovery of Salvarsan 606 in 1909 by Sahachiro Hata meant that syphilis could be treated without harming the body.

By contrast, before 1900, mercury had often been used to try and fight syphilis, but because mercury is poisonous, this type of treatment often harmed the patients who used it.

So really well done if your own response looks something like that model, especially if it was providing factual details from both the time periods.

And so now we're in a good position to move on to the second part of our lesson for today where we are going to think about the development of penicillin.

Magic bullets are chemical antibiotics.

Any type of substance which treats infections by destroying or limiting the growth of bacteria in the body is an antibiotic.

In the mid-20th century, non-chemical antibiotics were also developed, including penicillin.

Alexander Fleming, a British scientist, was responsible for discovering that penicillin, a type of mould, can attack and destroy bacteria.

During the 1920s, Fleming was experimenting with a type of bacteria called staphylococcus, which was responsible for causing many deadly diseases.

During a holiday in 1928, one of Fleming's samples of staphylococcus was contaminated by penicillin mould which had come from another nearby laboratory.

When Fleming returned, he noticed that in the contaminated sample, the staphylococcus next to the penicillin had been destroyed.

Realising the microbe-destroying potential of penicillin, Fleming published his findings in 1928.

However, Fleming did not believe that penicillin would work effectively against microbes in the human body.

So he only recommended its use as an antiseptic to fight bacteria outside of the body rather than as an antibiotic.

So let's reflect on everything we've just heard.

Who was the first person to discover that penicillin can destroy bacteria like staphylococcus? Was it Alexander Fleming, Gerhard Domagk, or Paul Ehrlich? Pause the video here, and press play when you're ready to see the right answer.

Okay, well done to everybody who said that the correct answer was A.

Alexander Fleming was the first person to discover that penicillin can destroy bacteria like staphylococcus.

And let's try another question.

This time we have a statement on the screen which reads: Fleming showed that penicillin worked as an antibiotic to cure infections, but is that statement true or false? Pause the video here and press play when you're ready to check your answer.

Okay, well done to everybody who said that that statement was false, but we need to be able to justify our response.

So why is it that that original statement was incorrect? Pause the video here, and press play when you're ready to check your answer.

Okay, well done to everybody who said Fleming did not believe that penicillin would destroy bacteria inside the body, so he did not attempt to develop it as an antibiotic.

In 1938, Fleming's findings about penicillin were rediscovered by two scientists, Howard Florey and Ernst Chain.

Florey and Chain conducted further experiments to test whether penicillin could be developed into an effective antibiotic.

Initial tests on mice indicated that penicillin could be used to treat bacterial infections effectively.

And so in 1941, Florey and Chain conducted their first test on a person.

Once again, this test revealed that penicillin was an effective antibiotic as their patient showed signs of recovery.

However, Florey and Chain's experiments also made it clear that it took a lot of time and energy to produce penicillin as an antibiotic which people could use.

Therefore, it was clear that if penicillin was to be used effectively, lots of money would be necessary.

When the USA entered World War II in 1941, its government was keen to protect the health of its troops in order to maximise fighting strength.

In 1942, the US government began funding Florey and Chain's work, and American pharmaceutical companies began mass producing penicillin.

In 1943, the British government, which was also fighting in World War II, also began to support the mass production of penicillin.

Consequently, by July 1944, 2.

3 million doses of penicillin had been produced to help treat infected soldiers.

So thinking about what we've just heard, what event encouraged the British and American governments to support Florey and Chain's work? Was it the Great Depression, the Spanish Flu, or World War II? Pause the video here, and press play when you're ready to see the right answer.

Okay, well done to everybody who said that the correct answer was C.

The Second World War, or World War II, encouraged the British and American governments to support Florey and Chain's work because they hoped that availability of penicillin would help them protect the health of more of their soldiers.

So we're now in a good position to put all of our knowledge about the development of penicillin into practise.

For Task B, we have two questions.

Firstly, I would like you to answer why might some historians argue that Alexander Fleming is not the only individual who deserves credit for the development of penicillin? And then I would like you to answer question two, which asks you, how did war benefit the development of penicillin? Explain your answer in one paragraph.

So pause the video here, and press play when you're ready to reflect on your responses.

Okay, well done for all of your effort on that task.

So firstly, I asked why might some historians argue that Alexander Fleming is not the only individual who deserves credit for the development of penicillin as an antibiotic? And your answer may have included: Alexander Fleming was the first person to discover that penicillin could be used to destroy bacteria, including staphylococcus.

Importantly, Fleming shared his findings about penicillin's bacteria-destroying potential with other scientists, but did not believe that it would work effectively against microbes in the human body.

Therefore, historians might argue that Howard Florey and Ernst Chain also deserve credit for the development of penicillin as an antibiotic.

This is because it was them, not Fleming, who conducted tests with penicillin to see if it could cure bacterial infections.

Whilst Florey and Chain were encouraged by Fleming's original discovery, it was their experiments and research which proved that penicillin was an effective antibiotic.

So well done if your answer to the first part of Task B looks something like that model.

And I then asked you, how did war benefit the development of penicillin? And your answer may have included: war benefited the development of penicillin as it helped ensure that Florey and Chain's research received government support and funding.

At the time Florey and Chain conducted their work on penicillin, Britain and the USA were fighting in the Second World War.

Both countries hoped to maintain their fighting strength by protecting the health of their soldiers.

Both governments financially supported Florey and Chain's work to ensure that penicillin could be used to treat wounded soldiers.

As a result of this support, it was possible to mass produce penicillin, ensuring that it could be used effectively as an antibiotic.

So again, well done if your own response looks something like that model which we've just seen.

And so now we're ready to move on to the third and final part of our lesson for today, where we are going to think about the impact of antibiotics.

The development of antibiotics, such as prontosil and penicillin, has had a major benefit for modern medicine.

However, the development and use of antibiotics has not completely overcome the challenges posed by disease-causing microbes.

The development of antibiotics helped save the lives of millions of people who previously would've died after developing certain infections.

For instance, it is estimated that 12 to 15% of British and American soldiers who were wounded during World War II would've died if they hadn't been treated with penicillin.

Furthermore, the success of penicillin encouraged scientists to continue looking for new antibiotics.

For instance, streptomycin was discovered in 1943 and was so powerful that it could even cure people suffering from tuberculosis.

These advances in the use of antibiotics helped to reduce the threat posed by infectious diseases in modern Britain.

Whereas infectious diseases accounted for 20% of deaths in 1919, this figure had fallen to just 1% by the year 2000.

So let's make sure we have a secure understanding of everything we've just heard.

What proportion of wounded British and American soldiers were saved from death by penicillin during World War II? Pause the video here, and press play when you're ready to see the right answer.

Okay, well done to everybody who said between 12 and 15%.

And let's try another question.

This time, I want you to write the missing word from the following sentence.

In 1943, a new antibiotic, streptomycin, was developed, which could even cure blank.

So what's the missing word? Pause the video here, and press play when you're ready to see the right answer.

Okay, well done to everybody who said that the missing word was tuberculosis.

In 1943, a new antibiotic, streptomycin, was developed, which could even cure tuberculosis.

Despite continued research, there have been some limits to the benefits of antibiotic use in modern medicine.

For one, antibiotics are only effective in curing people infected by bacteria.

If people suffer from diseases caused by viruses, such as flu or HIV, antibiotics cannot be used to cure them.

Furthermore, antibiotics have not always been used responsibly.

In some cases, antibiotics have been overused, and in other instances, courses of antibiotics have not been completed by patients.

As a result, because they are living microbes, some bacteria have been able to adapt and become resistant to common antibiotics.

One example of this is MRSA, which kills hundreds of people every year, especially in hospitals.

The World Health Organisation now considers the rise of antibiotic-resistant bacteria to be one of the most significant threats to public health as it makes certain infections much harder to treat and cure.

So thinking about what we've just heard, what is MRSA an example of? Is it an antibiotic-resistant bacteria, a magic bullet, or a new antibiotic? Pause the video here, and press play when you're ready to see the right answer.

Okay, well done to everybody who said the correct answer was A.

MRSA is an example of an antibiotic-resistant bacteria, and it is responsible for killing hundreds of people every year, especially in hospitals.

And why is it that antibiotics can't be used to cure infections like flu or HIV? Is it because the infections are too strong, because the infections are not caused by bacteria, or because the infections are caused by antibiotic-resistant bacteria? Pause the video here, and press play when you're ready to see the right answer.

Okay, well done to everybody who said the correct answer was B.

Infections like flu or HIV are caused by viruses, not bacteria.

And this means that antibiotics cannot be used to cure them.

So we're now in a good position to put all of our knowledge about the impact of antibiotics into practise.

How significant have antibiotics been in the fight against infectious diseases in modern medicine? I want you to make sure you're explaining your answer to that question.

Your answer should include the following things: the benefits of antibiotic use, the issues associated with antibiotic use, and an overall judgement on the question.

So pause the video here, and press play when you are ready to reflect on your response.

Okay, well done for all of your hard work on that task.

So I asked you, how significant have antibiotics been in the fight against infectious diseases in modern medicine? And your answer may have included: antibiotics have been significant as they have helped to cure many people suffering from infectious diseases.

For instance, prontosil helps cure pneumonia, and penicillin is used to treat a wide range of infections which might have previously resulted in death.

In fact, there's been a considerable fall in deaths from infectious diseases in Britain since the introduction of antibiotics.

These accounted for 20% of deaths in 1919 when few antibiotics were available, whereas they only accounted for 1% of deaths in 2000 when antibiotics were much more widely available.

This shows that antibiotics have helped make infectious diseases less deadly in modern Britain.

Nevertheless, whilst infectious diseases have become less deadly, the use of antibiotics has not completely overcome the threat they pose.

For instance, infectious diseases which are caused by viruses such as HIV cannot be treated using antibiotics as these only destroy bacteria.

Even more problematically, due to some irresponsible use of antibiotics, there are certain bacteria which have developed resistance to common antibiotics.

This includes MRSA, which is often found in hospitals.

Antibiotic resistance means certain diseases are becoming harder to cure, and so there is the risk that infectious diseases could become much deadlier again.

Overall, whilst antibiotic resistance in particular means that antibiotics may become increasingly less effective over time, there are still many millions of people who have been cured of infections by using these types of medicines since the early 20th century.

Because many of those people would likely have died without access to antibiotics, it is clear that their use has still been very significant for the fight against infectious diseases in modern Britain.

So well done if your own response looks something like that model answer which we've just seen.

And so now we've reached the end of today's lesson, which puts us in a good position to summarise our learning about the development of magic bullets and antibiotics.

We've seen that magic bullets like prontosil cured some infections safely and effectively.

Alexander Fleming discovered that penicillin can destroy some bacteria, whilst Florey and Chain developed it into an effective antibiotic.

The US and British governments supported the development of penicillin during World War II and used it to treat wounded soldiers.

Deaths from infectious diseases declined during the 20th century, but irresponsible use means that antibiotic resistance in some bacteria is becoming an increasingly serious issue.

So really well done for all of your effort during today's lesson.

It's been a pleasure to help guide you through our resources today, and I look forward to seeing you again in the future as we continue to think about medicine in Britain and health and the people.