DANVILLE, Pa. (CBS) Three infants have died at a Pennsylvania hospital after coming in contact with a common and typically harmless bacteria and investigators still aren't sure how it happened.
Eight premature babies -- already vulnerable and fragile -- contracted a waterborne bacterial infection at Pennsylvania's Geisinger Medical Center in Danville. Three of them died.
"We're building this shell around the patients to keep them safe and at what point did that break down? and that is what we are still trying to identify," said Dr. Mark Shelly, the hospital's director of infection prevention.
Doctors say its a common bacteria called pseudomonas that is found in liquids and that only a few types can lead to infection.
"It's really too soon to say exactly where the organism is coming from but what we have, the info we have so far suggests it's some place outside of the NICU and we are continuing to pursue that and confirm that as best we can," Dr. Shelly said
All of the babies infected were born under 27 weeks. Four of them have recovered and doctors say they're now in good health.
One is still receiving treatment.
"Our neonatal unit has never seen a situation involving infections like this," said Dr. Frank Maffei, the hospital's chair of pediatrics.
As medical officials work to learn how the organism got into the neonatal intensive care unit, the hospital is telling expectant mothers who could deliver prematurely to go elsewhere, for now.