Newborn babies in a nursery at the Royal Women's Hospital in Melbourne have fallen ill to a mystery bug.
AAP reports 15 babies in the hospital's intensive and special care nursery were quarantined when the illness emerged nine days ago.
Two had to have surgery for an inflammatory bowel condition.
A hospital spokeswoman said there was no danger to new arrivals.
Australian Nursing Federation state secretary Lisa Fitzpatrick said more than 1900 specimens had been taken to determine the cause of the outbreak.