M.P.
Staph is Staphylococcus bacteria what your daughter is probbaly suffering from is an infection caused by Staphylococcus aureus. (it may not be Staph aureus but more likely than not it is) Staph aureus is a natural bacteria on the skin and can get in to even the smallest cut. It has little to do with how clean you are it just lives there. Some types of infections can be very hard to get rid of and may need to be medically treated by IV antibiotics. However if you get rid of all the bacteria it could cause many more problems. This bacteria can be healthy for your skin. If your daughter is prone to infections you may want keep the areas clean (the ones that are most commonly infected). I am sure you have heard of all the good bacterias. I would suggest having a close relationship with you doctor. If you are not getting any where then get a second opinion. It does need attention. Dont take it lightly. I have also heard taking a vinager bath every once in a while helps. Try once a week. Wikipedia.com has some good articles on this subject as well.
I hope everything goes better for you! Good luck!
M.