Can I suggest that you check that she is in fact wiping herself properly? Is she wiping herself too hard, from back to front instead of the correct way.
Continuous UTIs could have an adverse effect on her kidneys. I hope you get answers before things get worse. Maybe talk to her about the symptoms if she can understand and aks hr to tell you as soon as she feels them. Having said that I had one a couple of years ago but had no of the common symptoms. Mine was found when I started vomitting and could retain slow sips of water, then developed a high temeperature which didn’t reduce with normal procedure and was taken to hospital by ambulance as I had a fall.

good nice story

How frustrating! Have you been able to get to the bottom if it? No pun intended.