For almost seven decades, we’ve routinely fed antibiotics to the animals we eat. That’s just a few years less than we’ve taken antibiotics ourselves. And for just about as long, it’s been clear that those antibiotic doses have been creating drug-resistant bacteria that pass from meat animals to make humans sick.
The first outbreaks of drug-resistant foodborne illness were spotted as early as the mid 1950s, when an epidemic of resistant salmonella swept through southeastern England. That was the first of waves of outbreaks that occurred over decades, some small and some very large and widespread. One of the largest foodborne outbreaks in US history, which made 634 people in 29 states and Puerto Rico sick in 2013-14, was tracked back to chickens that had been given antibiotics in their feed.
The connection isn’t universally accepted, of course. Most of the studies linking farm antibiotic use and human illness have been observational, not experimental — and that’s given ag and pharma room to insist that the case against farm antibiotic overuse isn’t solid. The argument has been that the bacterial traffic from animals to meat to humans isn’t proven — and until it can be established with 100 percent certainty, the practice of giving livestock preventative antibiotics should continue.
Now a new study, years in the making, goes further than any other to demonstrate that resistant bacteria can move from animals to humans via the meat they become. It also provides a model of how new surveillance systems might reduce that bacterial flow at its source on farms.
It’s just one study, but it possesses outsize significance, because it eliminates the uncertainty at the center of that bacterial flow. Outside of experimental conditions, it’s never been possible to prove that this antibiotic given to that animal gave rise to this bacterium that ended up in thathuman. But this new work dives so deeply into the genomics of bacterial adaptation in food animals and humans, it proves the link that ag would rather deny.
Good animal husbandry requires some use of antibiotics. Factory farming relies on antibiotics and that causes widespread resistance to antibiotics in humans. That’s a significant external cost that factory farmers should be paying for. Antibiotic use should be taxed.