Almost two years ago, my father was killed by a hospital-borne infection in the intensive-care unit of a well-regarded nonprofit hospital in New York City. Dad had just turned 83, and he had a variety of the ailments common to men of his age. But he was still working on the day he walked into the hospital with pneumonia. Within 36 hours, he had developed sepsis. Over the next five weeks in the ICU, a wave of secondary infections, also acquired in the hospital, overwhelmed his defenses. My dad became a statistic—merely one of the roughly 100,000 Americans whose deaths are caused or influenced by infections picked up in hospitals. One hundred thousand deaths: more than double the number of people killed in car crashes, five times the number killed in homicides, 20 times the total...