Antibiotics

Episode Summary

The widespread use of antibiotics when they're not really needed is a major issue in both agriculture and human medicine. Many doctors overprescribe antibiotics and regulations allow people to buy them over the counter. On farms, antibiotics are routinely injected into healthy animals as a preventative measure and also to fatten them up. But the bacteria don't care who is to blame for the overuse. They evolve resistance to the drugs, which could have disastrous consequences. Some estimates suggest drug resistant infections could kill 10 million people per year by 2050, more than currently die from cancer. The economic cost could be $100 trillion. The story of antibiotics started with serendipity. In 1928, Alexander Fleming didn't clean up his lab before a holiday. When he returned, he noticed mold had killed bacteria in a petri dish. But Fleming wasn't able to investigate further since he wasn't a chemist. A decade later, Ernst Chain, a chemist refugee from Nazi Germany, came across Fleming's old notes. Chain, along with Howard Florey and Norman Heatley, figured out how to mass produce penicillin, the first antibiotic. But Fleming warned that bacteria could be made resistant in the lab by exposing them to non-lethal doses. The problem hasn't been ignorance but incentives. Doctors and patients want to use antibiotics even when inappropriate to speed recovery. Farmers have an incentive to use low doses routinely to prevent disease and fatten animals, even though this breeds resistant bacteria. Tighter regulations are needed on agricultural and medical use. Denmark shows progress can be made. The country is famous for bacon but has strict controls on farm antibiotics. Improving conditions to reduce disease spread also appears to reduce the impact of routine antibiotic use. Ultimately the incentives need to change.

Episode Show Notes

In 1928 a young bacteriologist named Alexander Fleming failed to tidy up his petri dishes before going home to Scotland on holiday. On his return, he famously noticed that one dish had become mouldy in his absence, and the mould was killing the bacteria he’d used the dish to cultivate. It’s hard to overstate the impact of antibiotics on medicine, farming and the way we live. But, as Tim Harford explains, the story of antibiotics is a cautionary one. And unhelpful economic incentives are in large part to blame.

Producer: Ben Crighton Editors: Richard Knight and Richard Vadon

(Image: Penicillin Fungi, Credit: Science Photo/Shutterstock)

Episode Transcript

SPEAKER_02: Amazing, fascinating stories of inventions, ideas and innovations. Yes, this is the podcast about the things that have helped to shape our lives. Podcasts from the BBC World Service are supported by advertising. SPEAKER_00: Ryan Reynolds here from Mint Mobile. With the price of just about everything going up during inflation, we thought we'd bring our prices down. So to help us, we brought in a reverse auctioneer, which is apparently a thing. SPEAKER_01: Mint Mobile Unlimited Premium Wireless. How did it get 30, 30, did it get 30, did it get 20, 20, did it get 20, 20, did it get 15, 15, 15, 15, just 15 bucks a month? Sold. Give SPEAKER_00: it a try at mintmobile.com slash switch. New activation and upfront payment for three month SPEAKER_04: plan required. Taxes and fees extra. Additional restrictions apply. See mintmobile.com for full terms. SPEAKER_03: 50 things that made the modern economy with Tim Harford. SPEAKER_01: On a ramshackle pig farm near Wuxi in Jiangsu province, China, a foreigner gets out of a taxi. The family are surprised. Their little farm is at the end of a bumpy track through rice paddies. They don't get many foreigners turning up in taxis and asking to use the toilet. The stranger's name is Phillip Limbury and he runs a campaigning group called Compassion in World Farming. He's not here to berate the farmers about the living conditions of their pigs, although they are depressing. Sows are crammed into crates with no room to move. The living conditions of the family aren't much happier. The toilet, Limbury finds, is a hole in the ground between the house and the pig pen. No, Limbury's here to investigate if pig manure is polluting the local waterways. He's tried to visit the large commercial farms in the vicinity but they don't want to see him. So he's turned up on spec at a family farm instead. The farmer's happy to talk. Yes, they dump waste in the river. No, they're not supposed to. But that's okay, they just bribe the local official. Then Limbury notices something. It's a pile of needles. He takes a closer look. They're antibiotics. Have they been prescribed by a vet? No, the farmer explains. You don't need a prescription to buy antibiotics. And anyway, vets are expensive. Antibiotics are cheap. She injects her pigs with them routinely and hopes that'll stop them getting sick. She's far from alone. Cramped and dirty conditions on intensive farms are breeding grounds for disease. But routine low doses of antibiotic can help to keep disease in check. Antibiotics also fatten animals. Scientists are studying gut microbes for clues as to why that is, but farmers don't need to know why. They simply know they make more money from fatter animals. No wonder more antibiotics are injected into healthy animals than sick humans. In the big emerging economies where demand for meat is growing as incomes rise, the use of agricultural antibiotics is set to double in 20 years. The widespread use of antibiotics when they're not really needed isn't restricted to agriculture. Many doctors are guilty too, and they should know better. So should the regulators who allow people to buy antibiotics over the counter. But the bacteria don't care who's to blame. They busily evolve resistance to drugs and public health experts fear we're entering a post-antibiotic age. One recent review estimated that drug resistant bugs could kill 10 million people a year by 2050, more than currently die from cancer. It's hard to put a monetary value on antibiotics becoming useless, but the review tried. The figure it came up with? $100 trillion. The story of antibiotics starts with a healthy dose of serendipity. A young man named Alexander Fleming was earning a wage through a boring job in shipping when his uncle died, leaving him enough money to quit and enroll at St Mary's Hospital Medical School in London instead. There he became a valued member of the rifle club. The captain of the shooting team didn't want to lose Fleming when his studies were over, so he lined up a job. That's how Fleming became a bacteriologist. Then in 1928, Fleming didn't bother to tidy up his Petri dishes before going back home to Scotland on holiday. On his return, he famously noticed that one dish had become mouldy in his absence, and the mould was killing the bacteria he'd used the dish to cultivate. Fleming tried to investigate further by making more mould, but he wasn't a chemist. He couldn't figure out how to make enough. He published his observations, but nobody paid attention. A decade passed, and then more serendipity. In Oxford, Ernst Chain was flicking through back copies of medical journals when he chanced upon Fleming's old article. And Chain, a Jew who had fled Nazi Germany, was a chemist. A brilliant one. Chain and his colleague, Howard Flory, set about isolating and purifying enough penicillin for further experiments. This required hundreds of litres of mouldy fluid. Their colleague, Norman Heatley, rigged up a crazy-looking Heath Robinson system involving milk churns, baths, ceramic bedpans commissioned from a local pottery company, rubber tubes, drinks bottles and a doorbell. They employed six women to operate it, the Penicillin Girls. The first patient to get an experimental dose was a 43-year-old policeman who'd scratched his cheek while pruning roses and developed septicaemia. Heatley's makeshift system couldn't make penicillin quickly enough, and the policeman died. But by 1945, penicillin, the first mass-produced antibiotic, was rolling off production lines. Chain, Flory and Fleming shared a Nobel Prize. And Fleming took the opportunity to issue a warning. It is not difficult, Fleming noted, to make microbes resistant to penicillin in the laboratory by exposing them to concentrations not sufficient to kill them. Fleming worried that an ignorant man might underdose himself, allowing drug-resistant bacteria to evolve. But ignorance hasn't been the problem. We know the risks, but face incentives to take them anyway. Suppose I feel ill. Perhaps it's viral, meaning antibiotics are useless. Even if it's bacterial, I'll probably fight it off. But if there's any chance that antibiotics might speed my recovery, my incentive is to take them. Or suppose I run a pig farm. Giving routine, low doses of antibiotics to my pigs is the perfect way to breed antibiotic-resistant bacteria. But that's not my problem. My only incentive is to care about whether dosing my pigs seems to increase my revenues by more than the cost of the drugs. This is a classic example of the tragedy of the commons, where individuals rationally pursuing their own interests ultimately create a collective disaster. Until the 1970s, scientists kept discovering new antibiotics. When bacteria evolved resistance to one type, we could introduce another. But then the development pipeline dried up. It's possible that new antibiotics will start coming through again. For example, some researchers have come up with a promising new technique to find antimicrobial compounds in soil. Again though, this is all about incentives. What the world really needs is a new antibiotic that we put on the shelf and use only in the direst emergencies. But a product that doesn't get used isn't much of a money-spinner for drug companies. We'll need to devise better incentives to encourage more research. We'll also need smarter regulations as to how new antibiotics are used by doctors and farmers alike. Denmark shows it can be done. It's world-famous for its bacon and it strictly controls antibiotic use in pigs. One key appears to be improving other regulations to make farm animals' living conditions less cramped and unhygienic. That makes disease less likely to spread. And recent studies suggest that when animals are kept in better conditions, routine low doses of antibiotics have very little impact on their growth. The pig farmer in Wuxi meant well. She clearly didn't understand the implications of overusing antibiotics. But even if she had, she'd have faced the same economic incentives to overuse them. Ultimately, it's those incentives that need to change.