One in 25 patients in U.S. hospitals acquires an infection during their stay in the hospital, according to a comprehensive study released this week by the Centers for Disease Control and Prevention. Clean hands can help mitigate the problem, but getting hospital workers to use sanitizer regularly has proven tough. One design studio's clever solution? A door handle that encourages people to clean their hands every time they use it. The handle, PullClean, was developed by the British studio Agency of Design for Altitude Medical. It's a simple column that can be fitted on any pull door, with a blue paddle on bottom that dispenses a dab of hand sanitizer when pushed.