Girls, hi. What could cause urine smell in a child? My youngest daught…

Girls, hi. What could cause urine smell in a child? My youngest daughter has had a terrible smell from her diaper for a week now. I thought it was because of the diapers themselves, as we just opened a new pack. But these same diapers I also put on my older daughter at night, and she's fine, doesn't smell anything. ?‍♀️