Copyright © 2012 Massachusetts Medical Society. A 30-year-old woman calls you to report a 2-day history of worsening dysuria and urinary urgency and frequency. She reports having no fever, chills, back pain, or vaginal irritation or discharge. One month ago, you treated her with a 3-day course of trimethoprim–sulfamethoxazole for presumptive cystitis, and her symptoms resolved. She is otherwise...