UTI's must be treated with an effective broad spectrum antibiotic like Clavamox or clidimycin and for a long enough duration so all bacteria is eradicated. If not, they will refluorish, stronger and more resistant and reinfect her. In addition, the bacteria can become tolerant of the same antibiotic so the medication should be varied for best results.
Your baby should not eat dry food. Canned only so she gets adequate fluid. She should also be encouraged to drink as much as possible to keep the kidneys and bladder flushed. You can give her one daily drop of unsweetened (only) cranberry juice. That will reduce the PH of her urine and make herbladder inhospitable to UTI bacteria.
It is also possible these events may be triggered by stones or crystals. Depending on the findings , you may want to consider low ash, low magnesium food or even a renal diet if she would eat it.
Please let me know if you still have questions and how your baby is feeling. I will be happy to help further.
I hope she will be fine.