Q. A 29-year-old female comes to the physician’s office for lower abdominal pain and fever with chills for the past 3 days. She also complains of an increase in vaginal discharge with an unpleasant odor. Her periods are regular. She has had unprotected sexual intercourse with multiple partners in the past month. Her temperature is 101.4°F (38.6°C), pulse is 96/min, blood pressure is 120/80 mmHg, and respiratory rate is 16/min. Physical examination shows moderate lower abdominal tenderness without guarding and rigidity. Pelvic examination shows purulent vaginal discharge and cervical motion tenderness. Complete blood count shows leukocytosis with a left shift. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are elevated. A pregnancy test is negative. Which of the following is the most appropriate next step in the management of this patient?