Carolinas HealthCare System is stepping up its efforts to combat the spread of an antibiotic-resistant "superbug" that has claimed the lives of two Charlotte-area people in recent months and sickened more than a dozen others, officials said Sunday. Citing medical privacy laws, Carolinas HealthCare officials did not release specifics about the people who have died from carbapenem-resistant Enterobacteriaceae, commonly known as CRE, during a news conference Sunday. But because of the threat, officials said, the Charlotte-based hospital system has started screening patients from populations likely to have CRE. Once identified, CRE patients are isolated from other patients. When they're released, the hospital takes extra steps to decontaminate their rooms.