need advice on urinary tract infections

[mygirlchloe]

I have a 7 month old lab beagle mix that has had two urinary tract infections already. In fact she is not quite finished her second round of antibiotics. My problem is she has started peeing in the house again and is asking to go out about every 15 minutes and then coming in and peeing. I really don't know what to do and this is costing me a fortune! I don't know why she is getting them and the peeing in the house is frustrating. I don't want to have to keep her in her crate when I'm home because she is usually in it for 4-6 hour during the day when I'm at work and then again at night when she sleeps. Any suggestions would be greatly appreciated.

I should add that she was spayed about 2 1/2 weeks ago and that I've been using either an emzyne cleaner or white vinegar to clean up the accidents.

Frustrated and confused!