Try just pressing a clean tissue ONCE against the vulva, then drop it in the bowl. Wiping often is unconsciously done twice with the same tissue, transferring bacteria from near the anus back to the meatus, the end of the urethra, infecting it.
Also, try to urinate after each dilation or other contact with the vulva and meatus in particular.
I also suggest getting a hand bidet for use at home. This is basically a little spray nozzle with hose that connects to the toilet tank fill line, and lets you spray clean the bottom, after which you just pat dry with a clean tissue.
In the shower, a removable shower head on a hose can be used to similar purpose, to spray one's bottom clean.