41.

Antibiotics in Farming

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 Philip Lymbery, 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’re depressing. Sows are crammed into crates, with no room to move. The living conditions of the family aren’t much happier: the toilet, Lymbery finds, is a hole in the ground between the house and the pig pen. No, Lymbery’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 is 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 Lymbery notices something. It’s a pile of syringes. He takes a closer look. They’re loaded with 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 from getting sick.1

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 keep disease in check.2 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 that they make more money from fatter animals.3 No wonder that across the world, more antibiotics are injected into healthy animals than sick humans.4 In the big emerging economies, where demand for meat is growing as incomes rise, use of agricultural antibiotics is set to double in twenty years.5

The widespread use of antibiotics where they’re not really needed isn’t restricted to agriculture. Many doctors are guilty, too, and they should know better.6 So should the regulators who allow people to buy antibiotics over the counter.7 But the bacteria don’t care who is to blame. They busily evolve resistance to these antibiotics, and public health experts fear we are entering a post-antibiotic age. One recent review estimated that drug-resistant bugs could kill ten million people a year around the world 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: a hundred trillion dollars.8 You might think we’d be doing everything possible to preserve antibiotics’ life-saving power. You’d be wrong.

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 to enroll in 1903 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 for him. That’s how Fleming became a bacteriologist.9

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 moldy in his absence, and the mold was killing the bacteria he’d used the dish to cultivate. We now know that mold as Penicillium chrysogenum, the source of penicillin.10

Fleming tried to investigate further by making more mold, but he wasn’t a chemist—he couldn’t figure out how to make enough. He published his observations, but nobody paid attention.11 A decade passed, then more serendipity: in Oxford, Ernst Chain was flicking through back copies of medical journals when he chanced upon Fleming’s old article.12 And Chain, a Jew who’d fled Nazi Germany, was a chemist—a brilliant one.

Chain and his colleague Howard Florey set about isolating and purifying enough penicillin for further experiments. This required more than a hundred gallons of moldy fluid every week; another colleague, Norman Heatley, rigged up a crazy-looking 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, who became known as the “penicillin girls.”13

The first patient to get an experimental dose of this penicillin was a forty-three-year-old policeman who’d scratched his cheek while pruning roses and developed septicemia. 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, Florey, 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.”14 Fleming worried that an “ignorant man” might underdose himself, allowing drug-resistant bacteria to evolve. Yet 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 concern. 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, researchers could introduce another. But then the discoveries, and the development pipeline, dried up.15 It’s possible that new antibiotics will start coming through again. Some researchers, for example, have come up with a promising new technique to find antimicrobial compounds in soil.16 Again, though, this is all about incentives. Drug companies want to produce products that will be widely used. But what the world really needs is a new range of antibiotics 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 the drug companies. We’ll need to devise better incentives to encourage more research.*

We’ll also need smarter regulations to govern 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.17 One key appears to be improving other regulations, to make farm animals’ living conditions less cramped and unhygienic, which 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. And that is ultimately what needs to change.