One problem with antibiotic resistance is that, for most people, it remains abstract—right now its lethal impact is relatively small. Few of us have lost loved ones—yet. (The headline-grabbing methicillin-resistant Staphylococcus aureus, or MRSA, kills 20,000 people a year in the US, compared to the 600,000 who succumb to cancer.) So it’s difficult to envision a future that resembles the pre-antibiotic past—an era of untreatable staph, strep, tuberculosis, leprosy, pneumonia, cholera, diphtheria, scarlet and puerperal fevers, dysentery, typhoid, meningitis, gas gangrene, and gonorrhea.

But that’s the future we are headed for. The routine use of antibiotics and the reckless misuse in humans and animals accelerates resistance: We’re rewinding to a world where death begins in childbirth, where premature babies die, where newborns go blind from gonorrhea. Routine injuries become life-threatening infections. You could lose a limb, or your life, from a careless slip with a paring knife or an accidental fall in India. The risks of organ transplants and medical implants would outweigh any potential benefit. Go in for routine dental surgery and end up in a body bag. Explosive viral epidemics, such as the flu, prove especially lethal when they tag team with bacterial infections like strep. This is not the coming plague. It’s already upon us, and it spells the end of medicine as we know it. And that’s why Brady’s quest to revitalize antibiotic discovery is so crucial.

As a result of his calls for people from all over to send him soil, Brady keeps an entire room filled with Ziplock bags of dirt. Tim Schutsky for WIRED Brady sometimes describes his work as a kind of archeological dig: He is examining the remnants of a microbial civilization. Tim Schutsky for WIRED

Since 1939, when René Dubos, a researcher at Rockefeller University, smeared dirt across a Petri plate and isolated the antibiotic gramicidin, the search for antibiotics has largely been culture dependent: It’s limited to the finite percentage of bacteria and fungi that grow in the laboratory. If the chance of finding a new antibiotic in a random soil screen was once one in 20,000, by some estimates the odds have dwindled to less than one in a billion. All the easy ones have already been found.

Historically, it’s a search riddled with accidental discoveries. The fungal strain that was used to manufacture penicillin turned up on a moldy cantaloupe; quinolones emerged from a bad batch of quinine; microbiologists first isolated bacitracin, a key ingredient in Neosporin ointment, from an infected wound of a girl who had been hit by a truck. Other antibiotics turned up in wild, far-flung corners of the globe: Cephalosporin came from a sewage pipe in Sardinia; erythromycin, the Philippines; vancomycin, Borneo; rifampicin, the French Riviera; rapamycin, Easter Island. By persuading the right microbes to grow under the right condition, we unearthed medicinal chemistry that beat back our own microscopic enemies. But despite technological advances in robotics and chemical synthesis, researchers kept rediscovering many of the same easy-to-isolate antibiotics, earning the old-school method a derisive nickname: “grind and find.”

That’s why Brady and others turned to metagenomics—the study of all the genetic information extracted from a given environment. The technique originated in the late 1980s, when microbiologists began cloning DNA directly out of seawater and soil. Extracted and cut up into chunks, this environmental DNA could be maintained in the lab by inserting the foreign gene fragments into bacteria such as E. coli (thereby creating what’s known as an artificial chromosome). These clones contained libraries, a living repository for all the genomes of all the microbes found in a particular environment.

Using high-throughput DNA sequencing, scientists then searched these libraries and their census turned up such astronomical biodiversity that they began adding new branches to the tree of life. By some estimates, the earth harbors more than a trillion individual microbe species. A single gram of soil alone can contain 3,000 bacterial species, each with an average of four million base-pairs of DNA spooled around a single circular chromosome. The next steps followed a simple logic: Find novel genetic diversity, and you’ll inevitably turn up new chemical diversity.

At Lodo, chemists extract and purify organic molecules, looking for new chemical structures and, perhaps, that one perfect molecule which could save millions of lives. Tim Schutsky for WIRED

In 1998, Brady was part of a team that laid out a straightforward strategy for isolating DNA from the dirt-dwelling bugs, by mixing mud with detergent, inserting gene fragments into E. coli, and, finally, plating clones into Petri dishes to see what molecules they produced. By the time Brady set up his own lab at Rockefeller University, in 2006, he’d created a handful of novel compounds. Some had anticancer properties; others acted as antibiotics. He had studied the DNA plucked out of a tank filled with bromeliads in Costa Rica and produced palmitoylputrescine, an antibiotic that was effective in vitro against a resistant form of B. subtilis bacteria. Brady came to realize that he did not need to trek to some pristine or remote ecosystem to explore the world’s biodiversity. The requisite material for building new drugs could be found much closer to home.