Officials at Atlanta-based Grady Memorial Hospital are investigating a spike in Legionnaires' disease. Four patients who were recently hospitalized at Grady have contracted the bacterial infection in the past month, according to Grady's Web site. In a typical year, the hospital might see two or three cases. Matt Gove, Grady senior vice president, said parts of the 11th and 12th floors have been shut down while the hospital tests water and tries to determine if the disease is originating inside the hospital. About 80 beds out of 953 are closed for now.