The premature babies were being treated in a neonatal intensive care unit when they were infected. Five other babies were also sickened.
Officials with the Geisinger Medical Center in Danville, Pa., said they did not yet know the source of the infections, which occurred over several months starting in July. The hospital said it was diverting care of some premature babies to other local hospitals while it investigated the infections.
Dr. Rosemary Leeming, the chief medical officer at Geisinger, said at a news conference on Monday that all of the infected babies were “extremely premature.”