My mother always had a UTI, and finally the urologist put her on , Methenamine Hippurate Tabs. It must be taken with vitamin C. It gets rid of all the scarring and pockets from having frequent UTIs, so bacteria doesn’t have a place to hide. This solved her problem. She’s been on it for years and the urologist had suggested stopping it but my mother didn’t want to because it stopped the UTIs. So they’ve left her on it.
good luck !
What does her doctor advise?