For the next six weeks, Silka and roughly a dozen other senior personnel manned the parking-lot entrance, handing out bottles of Purell to the arriving doctors. They started a Hand Hygiene Safety Posse that roamed the wards and let it be known that this posse preferred using carrots to sticks: rather than searching for doctors who weren’t compliant, they’d try to “catch” a doctor who was washing up, giving him a $10 Starbucks card as reward. You might think that the highest earners in a hospital wouldn’t much care about a $10 incentive — “but none of them turned down the card,” Silka says.

When the nurse spies reported back the latest data, it was clear that the hospital’s efforts were working — but not nearly enough. Compliance had risen to about 80 percent from 65 percent, but the Joint Commission required 90 percent compliance.

These results were delivered to the hospital’s leadership by Rekha Murthy, the hospital’s epidemiologist, during a meeting of the Chief of Staff Advisory Committee. The committee’s roughly 20 members, mostly top doctors, were openly discouraged by Murthy’s report. Then, after they finished their lunch, Murthy handed each of them an agar plate — a sterile petri dish loaded with a spongy layer of agar. “I would love to culture your hand,” she told them.

They pressed their palms into the plates, and Murthy sent them to the lab to be cultured and photographed. The resulting images, Silka says, “were disgusting and striking, with gobs of colonies of bacteria.”

The administration then decided to harness the power of such a disgusting image. One photograph was made into a screen saver that haunted every computer in Cedars-Sinai. Whatever reasons the doctors may have had for not complying in the past, they vanished in the face of such vivid evidence. “With people who have been in practice 25 or 30 or 40 years, it’s hard to change their behavior,” Leon Bender says. “But when you present them with good data, they change their behavior very rapidly.” Some forms of data, of course, are more compelling than others, and in this case an image was worth 1,000 statistical tables. Hand-hygiene compliance shot up to nearly 100 percent and, according to the hospital, it has pretty much remained there ever since.

Cedars-Sinai’s clever application of incentives is certainly encouraging to anyone who opposes the wanton proliferation of bacterial infections. But it also highlights how much effort can be required to solve a simple problem — and, in this case, the problem is but one of many. Craig Feied, a physician and technologist in Washington who is designing a federally financed “hospital of the future,” says that hand hygiene, while important, will never be sufficient to stop the spread of bacteria. That’s why he is working with a technology company that infuses hospital equipment with silver ion particles, which serve as an antimicrobial shield. Microbes can thrive on just about any surface in a hospital room, Feied notes, citing an old National Institutes of Health campaign to promote hand-washing in pediatric wards. The campaign used a stuffed teddy bear, called T. Bear, as a promotional giveaway. Kids and doctors alike apparently loved T. Bear — but they weren’t the only ones. When, after a week, a few dozen T. Bears were pulled from the wards to be cultured, every one of them was found to have acquired a host of new friends: Staphylococcus aureus, E. coli, Pseudomonas, Klebsiella.. . .