Hi Zoyabean!
Kaitlyn's mom here, writing on her log-in - should get my own, love this site. It is interesting, was a great help to Kaitlyn as she went through her student visa process, and it helps me to feel more in touch with her somehow, as she is now what feels like a million miles away (she is in London; I, Mom, am in NC, USA). Anyway, I second what lots of people have said. Some thoughts:
My young stepson suffered for more than a year with burning urination when he was about 8 years old. We stopped the fruit juices, the burning stopped. They were way too acidic for his little body to process. So many people think fruit juices are good for you - but they are so high in calories and sugar, for one thing. And for children, the best thing to do is realllly water them down, or just stick with plain old water, and feed them fresh fruit. Alot of parents just hand out a fruit juice or "fruit" drink when kids are thirsty. aaargh Give them plain water. Eventually they will get used to it. So, anyway, it is not just the sugar, but the acid that can cause a problem.
I worked in women's health care for 16 years. Saw lots of women with UTIs. Always always tested to find out what bacteria caused it, because antibiotics are bacteria-specific, and you must have the right one to treat the bacterial culprit. That said, many were caused by improper wiping, causing fecal material to enter the urethra. These infections especially required a particular antibiotic. We always discouraged use of bubble bath, feminine deodorant sprays, powders, deodorant pads and tampons, etc. Anything scented "down there" was a possible problem. Also no fabric softener or dryer sheets, and some women did well double rinsing their laundry to remove all soap residue.
Again, one must always question the possibility of sexual abuse, as ugly as that sounds. I know you will investigate that aspect thoroughly.
Also, a condition which is called interstitial cystitis - that is a whole 'nother can of worms.
You mentioned that the mom is a vegan, I assume therefore she is somewhat health-conscious. Is she aware of the possible long term health issues that are being investigated as possibly being caused by over-prescribing and over-use of antibiotics? Bad enough to use short-term, though often necessary, but if that is what they are recommending long term, for 5 years . . . yikes!!!! I am not a "health nut", but wonder if some pro-biotics might help. Also, active culture yogurt, also possibly cranberry tablets. I know cranberry juice and tablets are acidic, but they also kill certain bacterias in the digestive and urinary tracts.
Anyway, just some thoughts before I head out the door to work in cold but sunny NC. . .
Amy