Three infants died from infections believed to have been caused by the same waterborne bacteria outbreak in a Pennsylvania hospital.

Eight other premature babies staying in the neonatal intensive care unit at the Geisinger Medical Center in Danville survived their infections.

Hospital officials determined the cause of the infection — Pseudomonas bacterium — but so far, tests of the unit where the infections occurred have come back negative.

The outbreak prompted the hospital to divert premature babies born at less than 32 weeks’ gestation, and some pregnant women, to other hospitals.

Dr. Frank Maffei, the hospital’s chair of pediatrics, said the Pseudomonas bacterium is a common germ that is usually harmless.

But he noted the bacteria can cause disease in “very fragile patients.”

The infant deaths “may have been a result of the infection complicating an already vulnerable state,” said Maffei.

Another hospital official, Dr. Mark Shelly, said the initial findings on the root of the waterborne germ indicate it likely didn’t originate in the NICU.

“It’s really too soon to say exactly where the organism is coming from, but the information we have so far suggests that it’s someplace outside of the neonatal intensive care unit,” said Shelly.