A 2-year-old girl is brought in by her parents for review following recurrent urinary tract infections. Over the past year, she has had four documented UTIs, each presenting with dysuria, frequency, and foul-smelling urine, but no fevers. All urine cultures grew E. coli. She was born at term, with normal antenatal scans. The child is allergic to penicillin. She is otherwise healthy and has achieved toilet training recently.