Miss Chung is a 29 year old female who has presented today with a two day history of frequency and dysuria. She denies abdominal pain, nausea or vomiting and does not think she has had a temperature. You note from her records she is twenty weeks into her first pregnancy, so far, it has been uncomplicated and her scans have been normal. Miss Chung has had lots of urinary tract infections in the past, the last one was eight months ago for which she had Trimethoprim. She also has mild Asthma and Irritable Bowel Syndrome. She is allergic to Penicillin. Examination reveals mild suprapubic tenderness and her observations are all normal.
Urine dipstick: leucocytes ++, nitrates ++, protein -, blood -, glucose –
What is the most appropriate treatment?