I just came across this topic and I see you have already sorted it out. Good for you! For anybody else who might be reading this and wonder about UTI's and immunosuppressants I would like to share my own experiences to serve as a warning:
Last November I was on 100mg of 6mp and 10mg of prednisone. Apart from some minor bladder irritation over the course of a couple of weeks I had no UTI issues. I have had multiple bladder infections in the past, so I would recognise the symptoms if I had one. No trouble peeing this time, no pain, nothing. Then I suddenly got ill. At first I figured it was the flu, but it did not seem to pass. I had regular bloodtests at the time, for the 6mp and my CRP (which is always elevated) was only slightly higher than normal, around 30. Nobody thought I had anything to worry about. But then I suddenly developed a sharp pain on the right side, which responded to paracetamol by the way, deep inside my body. Long story short: over the course of a week my pain got worse and worse so eventually my GI decided she wanted to see mee asap. Went in the same day and she looked at me and decided to immediately send me to the ER. My urine was tested and it was positive for UTI, with a CRP of 117 (literally developed over night) and a resting heartrate of 140bpm I was given iv fluids and iv antibiotics and then.... sent home with a 7 day antibiotics prescription for cipro.
Finished the antibiotics course and felt better. Although I never completely recovered. Went to my GP: no bacteria left in my urine, still a little blood however. But CRP dropped to 20, so everybody assumed it was just the aftermath of a nasty case of pyelonephritis and a beginning urosepsis. A week and a half later I saw my GI and she recommended I got another urine test, just to be safe. This visit was on a Friday and I agreed to go to my GP on Monday. Never made it because on Sunday I got a lot worse. I was rushed to the ER, again with a heart rate of 145 bpm, a slight fever and a lot of pain. Urine tested positive for UTI albeit not as heavily as before. Got iv fluids, iv antibiotics and was admitted. They admitted me to the wrong department however, where the resident GI decided it could be appendicitis or Crohn's flaring. They wanted to do an MRI before anything else. So I basically just laid there for two days, without receiving any antibiotics. On the third day I was peeing blood. I insisted on a new urinalysis and it was a good thing I did, because the results were not good. I had a CT scan to check for kidneystones (neg) and had to wait until the next morning to start antibiotics. The urologist and the GI disagreed about the type of antibiotics, but they decided on a pill form: trimethoprim. I was send home the same day.
Of course this turned out to be too little too late as the next evening I got so sick I was again admitted through ER. Uroseptic, with a dangerously low blood pressure and an extremely high heart rate. This time I ended up in the right department, with a katheter, a constant iv with fluids and continuous antibiotics iv. They also upped my prednisone. It took more than a week in the hospital to get it under control. And than I also got a c diff infection. It was a total nightmare and it has taken me a very long time to recover.
I am 100% sure that the fact I was on immunosuppressants played a major role in things getting so out of control. Apart from the failing doctors that is. I am seeing a urologist in two weeks to further discuss this topic, but please let my story be a lesson to always trust your own instincts when it comes to your health and to keep emphasizing the fact that you use immunosuppressants, which may cause you to need more antibiotics than an average person to conquer an infection.
Hope this helps someone.