Ethnobotany is a historically small and obscure offshoot of the social sciences, focused on the myriad ways that indigenous peoples use plants for food, shelter, clothing, art and medicine. Within this already-tiny field, a few groups of researchers are now trying to use this knowledge to derive new medicines, and Quave has become a leader among them. Equally adept with a pipette and a trowel, she unites the collective insights of traditional plant-based healing with the rigor of modern laboratory experiments. Over the past five years, Quave has gathered hundreds of therapeutic shrubs, weeds and herbs and taken them back to Emory for a thorough chemical analysis.

By revealing the elemental secrets of these plants, Quave has discovered promising candidates for a new generation of drugs that might help resolve one of the greatest threats to public health today: the fact that an increasing number of disease-causing bacteria are rapidly evolving immunity to every existing antibiotic. Without effective antibiotics, common bacterial diseases that are curable today will become impossible to treat; childbirth, routine surgeries and even the occasional nick could turn lethal. The widespread emergence of resistant bacteria already claims 700,000 lives a year globally. Experts conservatively predict that by 2050, they will kill 10 million annually — one person every three seconds. “We’re standing on the precipice of a post-antibiotic era,” Quave says. “We just haven’t fallen off yet.”

Wherever you are, whatever you are doing, bacteria are beside you, on you and within you. And not just a few bacteria, but immense communities as dense, diverse and entangled as a rain forest. Relationships within these microbial societies are so intricate and volatile that they make more archetypal ecological associations — the cheetah and gazelle, the honeybee and flower — seem cartoonish in comparison. Depending on how many of its own kind are present and who else is around, and on the available territory and food, a given bacterial species will ignore, assist or obliterate its microbial neighbors. To cope with such a mercurial existence, bacteria have evolved an astonishing array of chemical lures, signals and weapons. In the early 20th century, scientists discovered that some of these molecules, if isolated and replicated en masse, could wipe out certain disease-causing bacteria. In their modern forms, antibiotics appear entirely artificial. But most of them come from nature. We did not so much invent antibiotics as borrow them from the very creatures we were hoping to overpower.

Between the 1940s and 1960s, the golden age of antibiotic discovery, researchers and pharmaceutical companies harvested such molecules from soil microbes and chemically tweaked them into dozens of new commercial drugs. Some antibiotics, most famously penicillin, came from fungi, but soil bacteria were so abundant and so easy to collect that they remained the center of attention. Researchers soon discovered, though, that only about 1 percent of all bacterial species could be grown in sterile laboratory conditions. By the 1970s, scientists had squeezed almost every potential drug out of this small circle of amenable microbes. In subsequent decades, many large pharmaceutical companies turned away from nature as a source of antibiotics, diverting resources to the promising new field of synthetic drug development.