We’re in a medical crisis, as bacteria that can resist antibiotics become more common. But, as I write in my new New York Times columnas I write in my new New York Times columnas I write in my new New York Times column, antibiotic resistance isn’t just limited to the doctor’s office. Bacteria all over the world have genes that make them resistant to our best drugs–bacteria living in caves, in ice, in the ocean floor, and in the dirt outside your door. And they probably had those genes long before doctors started using antibiotics.

Scientists have long considered the rise of antibiotic resistance one of the most striking examples of evolution in our own time. Our growing