For years, public health experts have warned us that deadly bacteria are developing resistance to all our available antibiotics. This week, researchers reported the first known U.S. case of an Escherichia coli infection resistant to colistin, a harsh drug seen as a last resort to knock out stubborn infections. The finding, described in the American Society for Microbiology journal Antimicrobial Agents and Chemotherapy, is no big surprise to researchers tracking the rise of resistant bacteria. The resistance gene, known as mcr-1, was discovered in E. coli in China last year, and has since cropped up in Europe.
As the United States crosses the same ominous milestone, research to understand resistance and develop new drugs is surging ahead. As Science reported earlier this month, evolutionary biologists have recently revisited old dogma about how best to prescribe antibiotics—revealing that trusted strategies such as using a high dose may not actually help prevent resistance.