Antibiotic Resistance: The Bugs You Can’t Kill

CUSCO, PERU — An elderly woman wearing five sweaters shuffled through her purse to find the pills she had been taking. She pulled out a small sheet of four pills and another sheet of two pills.

This woman, like many patients at the clinic, had used antibiotics to cure her common cold, taking two pills here and three pills there as soon as her throat started to hurt. After one or two days, she’d be cured and would stop taking the pills.

In the United States, federal law states that the purchase of all antibiotics requires a…