i JUST noticed you are from jersey as well. Where abouts are you from?

I went through something very similar with Lady last winter. She battled two different strains of E-coli which is what I suspect hers is,too, since that's what causes over 80% of uti's.

Apparently E-coli has become very resistent to antibiotics. I was fighting a post surgical infection at the same time so I also brainstormed with my infectious disease doctor when Lady didn't respond to antibiotic after antibiotic.

What I learned is that there is no one drug that will kill E-coli anymore even with a culture. It's hit or miss. We tried everything as you did and it does get expensive, doesn't it? I have so many rejected antibiotics here I could open a pharmacy. You keep trying all the different oral antibiotics. Have they tried the sulfa drugs yet? That used to be the best one to try. If they all fail, then they have to try IV antibiotics.

We got lucky with Lady. My vet decided to try Furantoin along with erythromycin and it finally worked. Furantoin is weird, not an antibiotic, but has something to do with keeping the bacteria from adhering to the bladder wall, I think. Lady has stayed on a maintenance does ever since to prevent uti's since she is a diabetic and so prone to them.

It took about 6-8 weeks to find the right antibiotic and to clear it up. I spent a fortune, The furadantoin is expensive for little dogs because they have to get the liquids because the capsules are too big. It is about $80, but was/is worth every penny.

My daughter suffered with constant UTI's when she was little. I took her to a homeopathic doctor and he gave us Collodial Silver. Now it was a miracle cure for her and I bet it would work with your dog too. All you do is give them drops twice a day until you see no evidence of an infection. Good luck!