2018-12-01_Discover

64 DISCOVERMAGAZINE.COM

FROM TOP: GAUTAM DANTAS/SCIENCE; STEVE JURVETSON VIA FLICKR; MATT MILLER/WASHINGTON UNIVERSITY SCHOOL OF MEDICINE

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When Gautam Dantas irst

observed bacteria eating

antibiotics, he was sure there had to be

some mistake. The year was 2007, and

he was trying to coax microbes to turn

plant waste into biofuels. Dantas was a

postdoctoral researcher in the Harvard

University lab of George Church, a

pioneer in genetics research. As part of

his investigation, Dantas had exposed

one group of soil microbes to a dose

of antibiotic, which he igured the

bacteria wouldn’t eat. A week later, a

group grown on a diet of plant matter

— and exposed to no antibiotics

— had grown only a little. In the

dishes illed with antibiotic, however,

most of the microbes were having a

picnic. Instead of proving deadly, the

antibiotics were providing sustenance.

“We igured we’d probably made a

mistake,” Dantas recalls a decade later.

He’s now a professor of pathology,

immunology and biomedical

engineering at Washington University,

managing a lab with more than a

dozen researchers studying everything

from biofuel production to the human

microbiome. But the mystery of those

antibiotic-eating bacteria has remained

a personal obsession.

Earlier this year, after hundreds of

experiments, Dantas inally published

his solution in Nature Chemical

Biology. What he discovered provides

important insights into antibiotic

resistance, the precipitous increase in

bacterial immunity to what should

be killer drug doses. Public health

oficials now consider it a medical

crisis. Every year, some 700,000 deaths

are attributed to pathogens that are

resistant to penicillin and other drugs

designed to kill them — largely in

A TASTE FOR PENICILLIN

Biologists have known bacteria

could consume antibiotics since the

early ’60s, but the knowledge was

neither widespread nor deep when

Dantas accidentally witnessed his

irst antibiotic feast. Intrigued, he

decided to follow up on forgotten old

studies by surveying the phenomenon

comprehensively. He bought all

the relevant drugs listed in the lab’s

microbiology supply catalog, and

collected soils from public parks,

secluded forests and cornields that

were fertilized with manure. All 18

drugs were eaten up by microbes

in his soil samples, especially

alarming because the concentrations

were 50 to 100 times greater than

ordinary antibiotic-resistant bacteria

can tolerate.

Published in Science in 2008, the

response to overprescription and

careless disposal. With any luck,

Dantas’ hungry bacteria will help, by

preventing resistance from evolving

in the irst place.

The Antibiotic Eaters

Researchers design bacteria to gobble up antibiotics in the environment, before microbes

have a chance to turn deadly. BY JONATHON KEATS

Gautam Dantas (above) discovered, while

working in George Church’s lab at Harvard

University, that bacteria can consume

antibiotics.

George

Church

Prognosis