Hi C.,
Did your daughter start eating a new baby/toddler food around the time the rashes started? Our second child used to get really bad diaper rashes like this, from certain foods. Tomatoes and other citrus food were the worst. But even peaches, plums, berries and grapes did it to a certain extent.
Is she eating the diced, canned peach/pear combo (Dole probably)? That caused our son's first really bad reaction. When I looked at the ingredients, I found that pineapple was listed. The pineapple wasn't noticeable, looked just like pear unless you look up close.
I would try backing off of all fruit (except banana which should be fine) until it clears up, then try them one at a time again (several days apart) and see if there is a connection.
For diaper rash ointment, our doctor recommend "Triple Paste". It is REALLY thick and sticks well and stays on a long time. This would help it heal faster. (You'd put it on after the antibiotic ointment.)
Good luck!
-D.