Hospitals fighting the spread of antibiotic-resistant bacteria are engaged in a self-preserving struggle, not only against the bacteria but also quite possibly against each other. A new mathematical model suggests that in urban areas, the presence of other hospitals gives each hospital an economic incentive to relax its infection control procedures, even though the overall result is bad for society.
In their model, David Smith of the National Institutes of Health in Bethesda, Md., and his coworkers portray infection control as a strategic game in which each hospital chooses to spend a certain amount on measures to prevent infection and thereby save money that it would otherwise have to spend on infected patients. Because a patient may acquire a drug-resistant bug in one hospital and then carry the infection to another, each hospital's choices about how vigilantly to fight infection can affect the success of efforts by other hospitals.
If Hospital A fights infection acti