Geisinger Medical Center in Danville, Pennsylvania, is working to determine the source of a waterborne germ which seems to have infected at least eight infants in the hospital's neonatal intensive care unit (NICU), the Associated Press reported.
All the infants were born at less than 27 weeks gestation.
Three of the infants have died, officials said. The hospital added that four babies have recovered, and one is still being treated with antibiotics.
Meanwhile, the hospital is sending newborns born at less than 32 weeks to other facilities, and mothers expected to give birth at those weeks, to other facilities, as it works with state and federal health authorities to ensure the bacteria has been eradicated.
The infections were caused by the Pseudomonas bacterium, a usually harmless bacteria found in plants, dirt, and water, as well as in armpits and genitals, which can sometimes cause disease in "very fragile patients," Danville's chair of pediatrics Dr. Frank Maffei told a news conference.
He added that the deaths may have been due to the fact that the infection complicated an already vulnerable state.
The water supply and surfaces in the NICU have tested negative for the infection.
Dr. Mark Shelly, Geisinger's director of infection control and prevention, said he believes the bacteria originated outside the NICU, and noted that the investigation may not reveal the source of the infections.
The hospital's NICU treats over 600 babies each year.