A few years ago, while doing research for my book on the beneficial microbes that share our bodies, I went on an inadvisably frenetic weeklong reporting trip that spanned five cities and three time zones. On the final night, I wearily picked up the phone in my hotel room to order some food, and noticed a label on the receiver. It said: Antibacterial handset. It was a perfect reflection of the world’s attitude to bacteria. They’ve existed for billions of years. They are everywhere, including within us. They influence our lives, safeguard our health, and shape our bodies. I had been traveling for days to learn more about them. And yet, even my phone wanted to kill them.
It wasn’t always like this. Antonie van Leeuwenhoek, the Dutchman who first discovered the microbial world in the late 17th century, was delighted to learn that multitudes of living things existed below the threshold of our perception. Even when he saw microbes in the plaque between his own teeth, he was more amazed than repulsed. Microbes only became synonymous with disease and disgust in the 19th century, when, in quick succession, biologists realized that bacteria caused illnesses like cholera, leprosy, gonorrhea, tuberculosis and more. And so they became villains: things we needed to destroy, lest they destroy us.