Really Bad UTI

"You were right," said Dr. Rosen when I answered my cell phone. "She has a really bad UTI."
"It was just a wild guess, really," I said. "Because when we were at physical therapy Monday she said 'My bottom hurts.' She'd said that the Thursday before too, when the PT asked her if the range-of-movement exercises were hurting her. We didn't know if it was arthritis in her hips or pelvis from previous fractures or if it was a bladder infection."
"Well, you know your mother," Dr. Rosen insisted. "You know how to interpret what she says. I'm going to start her on Levoquin and when I get the results of the culture we can see where to go from there."
I put down the cell phone and reflected: all that effort yesterday to get the urine sample, and it turns out to have been very important.
She could have had it for weeks without anyone knowing or treating it. Perhaps she did have it for weeks. There's no way to know until she makes some kind of vague statement or becomes really angry and combative.
It's a complete guessing game, and it's up to me. If I am not alert enough to the cues, she will continue to have an infection.
Will this UTI be treatable by antibiotics taken by mouth? Or will she be ordered onto medication by IV again? In that case, she will have to go to skilled nursing or the hospital in order to have the IV.
She has been on Macrodantin (nitrofurantoin), 50 mg at bedtime, for a month in order to prevent bladder infections, but I guess it doesn't combat whatever bacteria she got this time.
If she has a BM in her Depend and sits in it for a while, perhaps there's no antibiotic that can prevent an infection. This occurred on Monday and Tuesday of this week. On Monday when I toileted her after physical therapy, I found a bowel movement in her Depend, and yesterday when she insisted on using the bathroom just before her catheterization, there was a smaller one.
Usually she demands to use the toilet for a BM, but if I don't take the time to invite her to the toilet after lunch, I guess it just happens.
I don't know what to do about this constant threat of bladder infections.
Perhaps in a nursing home they could do catheterizations more often, discovering and treating them sooner. But our try at a nursing home in March was a disaster.
Next week I plan to be out of town, so I'm just grateful we got started on treating this before I fly to Santa Fe.