In a new approach to reducing the scourge of hospital-acquired infections, a team of scientists has been testing thousands of microbe samples from a Chicago hospital to learn how a medical building might make patients sicker.

Data from the three-year Hospital Microbiome Project are still being analyzed. So far the team has found factors including ventilation and humidity, and design features such as furnishings and fixtures, affect the kinds of bacteria people encounter inside a hospital in ways that impact their health. The...