In 1928, the British chemist Alexander Fleming returned from a vacation in the countryside to find that his lab was a frightful mess. There was, for example, a pile of Petri dishes in his sink, each of which contained a carpet of Staphylococcus aureus—a bacterium that can cause severe skin infections. On one such carpet, Fleming noticed that a bit of mold had landed, and carved out a kill-zone of slaughtered bacteria. From that mold, Fleming isolated a chemical called penicillin, and kicked off the modern antibiotic era.
Like penicillin, all our antibiotics were created naturally by microbes to suppress or kill other microbes. We then found and exploited these weapons. Fleming himself was always clear about giving due credit: “I did not invent penicillin. Nature did that. I only discovered it by accident.” His successors were more deliberate, searching for new antibiotics among microbes that live in soil, oceans, and other habitats. Now, many are screening the human microbiome—the communities of microbes that share our bodies. And their searches are already paying off.
Teruaki Nakatsuji and Richard Gallo from the University of California, San Diego, have discovered that some bacteria which naturally live on human skin produce chemicals that kill S. aureus—the same species that Fleming was studying. But rather than harvesting said chemicals, the duo went after the bacteria themselves—isolating them from people with a skin disease called atopic dermatitis (eczema), growing them, and adding them to a cream. The result: a personalized ointment for killing S. aureus—and hopefully treating eczema—using bacteria that come from a person’s own skin.