A 28-year-old woman G2P1LC1AB0, currently 22-weeks pregnant, presents with a 3-day history of urinary frequency and dysuria. She is in no acute distress, without fever or vaginal discharge, reports “The baby is really moving around a lot” and denies GI symptoms. Fundal height is consistent with gestational age and FHT= 140 BPM and regular. UA dip in office is positive for leukocyte esterase and nitrites, yielding a working diagnosis of lower UTI. Which of the following antimicrob...