A 30-Year-Old Woman, Gravida 1 Para 0, at 14 Weeks

A 30-year-old woman, gravida 1 para 0, at 14 weeks gestation comes to the office for a routine prenatal visit.  She has had no abdominal or pelvic pain, vaginal bleeding, or leakage of fluid.  The patient had mild nausea and vomiting earlier in the pregnancy that has resolved.  Review of systems is negative for hematuria, dysuria, and urinary frequency.  The patient has no chronic medical conditions and has had no previous surgeries.  She takes a prenatal vitamin and an iron supplement daily.  The patient has no known drug allergies.  She does not use tobacco, alcohol, or illicit drugs and runs 3-4 miles nearly every day.  Blood pressure is 100/60 mm Hg and pulse is 78/min.  BMI is 24 kg/m².  The fetal heart rate is 150/min by bedside Doppler ultrasound.  Initial prenatal laboratory results were normal except for a urine culture, which grew pansusceptible Streptococcus agalactiae.  Which of the following is the best next step in management of this patient?

A) No treatment now; collect rectovaginal culture at 36 weeks gestation and, if positive, penicillin prophylaxis during labor
B) No treatment now; repeat urine culture now and, if positive, treatment with amoxicillin
C) Treatment with amoxicillin now; penicillin prophylaxis during labor
D) Treatment with amoxicillin now; repeat urine culture in 4 weeks and, if negative, no further treatment
E) Treatment with amoxicillin now, then daily suppression with amoxicillin until delivery