The infants at the Geisinger Medical Center in Danville, Pennsylvania, neonatal intensive care unit were tiny, with some born 27 weeks premature.In July, some started to get ill. One by one, the number of sick babies climbed to eight. Between August and September, bacterial infections claimed the lives of three of them.At a news conference last month, officials at the hospital, which is about 150 miles northwest of Philadelphia, said they were at a loss about the source of the infections.But Friday, the hospital announced that it had found the root cause: the process it used to prepare donor breast milk."Our infection control team has traced the bacteria to the equipment used in measuring donor breast milk, which helps premature infants with their nutritional needs," Dr. Edward Hartle, executive vice president and chief medical officer at Geisinger, said in a statement."We would like to extend our sincere apologies to the families who have been affected by this incident," he said, adding that the hospital knows "that the public holds us to the highest standards."The bacteria, Pseudomonas aeruginosa, likes moist environments and grows in water but only presents a danger to extremely fragile patients, such as underdeveloped babies who already have a compromised immune system.Of the five surviving infants who got sick, one has been discharged, and the others remain hospitalized.The hospital, with the help of the Pennsylvania Department of Health, used DNA testing to determine the cause of the infections, Hartle said.The hospital said it changed the breast milk preparation procedure Sept. 30 to "single-use equipment to measure and administer donor breast milk.""We have had no new cases of infants becoming ill from pseudomonas in the NICU since making this change," Hartle said, emphasizing that "the donor breast milk at Geisinger is safe, and we are certain the milk itself was not the cause of the exposure."The hospital, which was already diverting care of some premature babies to other local hospitals while it investigated the infections, said that it was continuing to divert mothers "delivering at less than 32 weeks and babies born prematurely at less than 32 weeks" while it consulted with health authorities about resuming normal operations.At least one of the families whose child died has filed a lawsuit against the hospital. Matt Casey, a lawyer representing two out of the three families whose infants died, said the hospital's statement "raises more questions than it answers.""They haven't told these families anything about the details of when they knew about this and what they did about it prior to their babies being admitted to that NICU," he said.Abel Cepeda was born to Casey's clients, Zuleyka Rodriguez and Luis David Cepeda, of Hazle Township, Pennsylvania, on Sept. 24. He died Sept. 30, the same day that the breast milk process was changed."His parents were told that they didn't know why he died," Casey said.A day before the October news conference in which the infections were announced, the parents got a call telling them the cause of their baby's death was a bacterial infection, he said."We are going to get wholly to the bottom of who knew what, when," he said.The hospital declined to comment on the lawsuit.This article originally appeared in The New York Times.(C) 2019 The New York Times Company Click here to read full news..