Do you happen to know what the bacteria is that's causing the UTIs and have you heard of D-Mannos? It appears to be working for some people but has to be used regularly once the infection is gone (to keep them at bay) if you have a chronic problem. I believe it mainly works on e-coli and of course the sites that sell it say it works for other bacteria as well. It's worth a shot if you haven't tried it already.
The reason I ask if you know the bacteria is, I thought I was having chronic UTIs (for which I did try D-Mannos) but nothing but blood in the urine was showing up. The situation was further complicated by the fact that I'm allergic to Macrobid, giving me what appeared to be incredible infections with high fever, flank pain, congestion, etc., but it was the Macrobid and the infections turned out to be a urethral condition that I've just recently (within the last two weeks after what seemes like an eternity) cured with estrogen cream. I'm telling you, it's been one heck of a conundrum between the C-Diff and seemingly chronic UTIs. While Macrobid is supposedly safe regarding C-Diff, it did bring it back for me. I never should have even condidered taking it before making sure I had a bacterial condition.
A few doctors who are not at all on their game think I'm neurotic because of the negative C-Diff tests and negative bacterial tests for my urine. I hate to bash doctors, they do their best but they're often woefully misinformed and disinterested in solving problems. It's black and white for most of them. And they're trying not to get sued, which is undertandable. Even the doctor who gave me the estrogen cream upon request, when asked if it was absorbed into the blood, said no. Of course this is incorrect. Anyway, C-Diff is awful. There are worse things to have but in my life, this has been a disaster.
The other thing I'm going to write only as information in case it's useful to anyone, I took massive doses of vitamin C trying to thwart these 'UTIs' and as it turns out, acidic foods and drinks profoundly irritate this problem. I finally diagnosed the problem by process of elimination when even the acid in a glass of Sprite caused discomfort after a brief stretch of relative comfort. I found the condition on the internet after two doctors could find no bacteria but always trace blood. I suggested to my GYN trying the estrogen (which was a recommendation from the internet) so she, being very nice, agreed to try and within a week it was gone. Of course, with estrogen you really have to be wise in how you use it. I use the tiniest amounts every two, three days but the chronic irritation is thankfully totally gone - and I even put lemon on my fish last night with no trouble. For the moment the C-Diff and urinary tract irritation are gone. I'm in paradise and I wish this for you and everyone else going through this.
I hope you find a solution to this awful cycle you are in and I will pray for you. I am so sorry. I truly understand how you must be feeling. I apologize for the long post but it's throught posts like this and on the internet that I solved my problems. I'm trying to pass it on.