Week 1: A future without antibiotics?

Introduction

Welcome to Week 1 of this free course, Understanding antibiotic resistance.

In this week you will read about common bacterial pathogens and how antibiotics can be used to treat bacterial infections. You will then step back in time, through the medium of video, to consider how and with what success infections were once treated. After a brief review of key scientific advances that heralded the discovery of antibiotics, you will consider how these life-saving drugs revolutionised medical care.

Back in the present, you will analyse data from different countries highlighting the growing problem of antibiotic resistance worldwide. You will be introduced to factors, covered in more detail later in the course, that have contributed to this problem.

Finally, you will listen to scientists discussing the potential threat to modern medicine of antibiotic resistance and will begin to form your own opinion about it.

Start by watching the video below which reveals how the natural processes of bacteria are exploited to fight infections – and how bacteria fight back!

Download this video clip.Video player: Video 1

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Transcript: Video 1 Antibiotics.

NARRATOR:

Microbes, mostly tiny bacteria, make up around 90% of the cells in a typical human body and 10% of our body weight. Most of them are in our gut and on our skin. Many microbes are beneficial, for example, helping us to digest our food. Only a tiny fraction cause disease, and are usually kept in check by our immune system. But when they aren't, microbes also help us to fight back.

Bacteria cause disease when they are able to reproduce in the body. They produce harmful substances called toxins, which damage tissues and organs. But in nature, microbes can also produce agents called antibiotics to protect themselves against competitors.

PROFESSOR CHARLES COCKELL:

It's a tough world out there. And you might think that you just see competition in the savannas of Africa. But in fact, the microbes fight each other as well. And in fact, like martial arts, they have ways of fighting other microbes with particular moves. And one move they have is to produce antibiotics. These are compounds that allow them to kill other microbes and take all the food for themselves, all the resources that they need. And so the competition between microbes results in these very sophisticated antibiotic molecules.

NARRATOR:

The discovery of antibiotics and their power to fight bacterial disease began with Alexander Fleming. He observed the mould penicillium notatum accidentally growing on a sample of staphylococci, and saw it had killed the surrounding colonies of disease causing bacteria.

DR PAULA SALDAGO:

All antibiotics work by disrupting a critical function in the bacterial cell. For example, penicillin, discovered in 1928, prevents the cell from renewing it's cell wall during growth. Eventually, the cell wall weakens and bursts.

NARRATOR:

By the 1950s, the use of antibiotics had revolutionised the treatment of previously untreatable infectious diseases. In 1967, the Surgeon General of the United States of America, William Stewart, declared, ‘The time has come to close the book on infectious diseases. We have basically wiped out infection in the United States.’ But Stewart's optimism proved premature.

PROFESSOR CHARLES COCKELL:

The bad news is that microbes can become resistant to antibiotics, and they can change their biochemistry in order to adapt to these antibiotics and prevent the antibiotics from damaging the cell.

NARRATOR:

It's standard evolutionary behaviour. When bacteria reproduce, chance mutations occur. Most will be useless. But sometimes there will be one that will protect the bacterium against a particular antibiotic. While most of the bacteria succumb to the antibiotic, the one that survives goes on to reproduce and replicate the resistance. And bacteria reproduce very fast.

DR PAULA SALDAGO:

The good news is that scientists are developing new synthetic antibiotics that target resistant bacteria.

NARRATOR:

But who knows whether one day a mutated bacterium might become resistant to all synthetic antibiotics, a super, super bug.

[MUSIC PLAYING]

End transcript: Video 1 Antibiotics.

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Video 1 Antibiotics.

By the end of this week, you should be able to:

• recall why pathogenic bacteria pose a threat to human health
• define the term antibiotic and give examples
• describe the importance of antibiotics in modern health care
• analyse antibiotic data and make simple deductions about antibiotic use and resistance patterns
• discuss the consequences of a future without antibiotics.

Although this is an introductory course to antibiotic resistance, it assumes that you have a basic understanding of DNA and proteins. If you are unfamiliar with these concepts, you may want to try our free OpenLearn course What do genes do? [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)] or listen to our set of audios on DNA, RNA and protein formation before you start this course.