A 38-year-old woman, gravida 5 para 4, at 10 weeks gestation comes to the office for an initial prenatal visit. She feels well and has no concerns. The patient takes prenatal vitamins and has a history of type 2 diabetes mellitus that is currently managed with insulin. She has no vaginal bleeding or pelvic pain. The patient reports no urinary urgency, hematuria, or dysuria. She does not use tobacco, alcohol, or illicit drugs. Temperature is 36.7 C (98.1 F) and blood pressure is 130/80 mm Hg. BMI is 29 kg/m². The fetal heart rate is 155/min on Doppler ultrasound. Physical examination shows no abnormalities. A clean-catch urine culture from today's visit grows 100,000 colony-forming units/mL of Escherichia coli. Which of the following is the best next step in management?

Question

A 38-year-old woman, gravida 5 para 4, at 10 weeks gestation comes to the office for an initial prenatal visit. She feels well and has no concerns. The patient takes prenatal vitamins and has a history of type 2 diabetes mellitus that is currently managed with insulin. She has no vaginal bleeding or pelvic pain. The patient reports no urinary urgency, hematuria, or dysuria. She does not use tobacco, alcohol, or illicit drugs. Temperature is 36.7 C (98.1 F) and blood pressure is 130/80 mm Hg. BMI is 29 kg/m². The fetal heart rate is 155/min on Doppler ultrasound. Physical examination shows no abnormalities. A clean-catch urine culture from today's visit grows >100,000 colony-forming units/mL of Escherichia coli. Which of the following is the best next step in management?

Quizplus · Accepted Answer

11ec25c8_d279_89f1_bc81_a91ec4a3d37d_MD0003_00 Asymptomatic bacteriuria (ASB) is the growth of ≥100,000 (10⁵) colony-forming units/mL of a single bacteria from a clean-catch urine specimen in the absence of urinary tract infection symptoms. Prepregnancy diabetes mellitus, as in this patient, is a risk factor. Screening and treatment for ASB is typically not performed in the general population because it does not decrease the rates of symptomatic infection or adverse outcomes. In contrast, pregnant women have an increased risk of pyelonephritis and complications (eg, preterm delivery, low birth weight) associated with ASB. This is likely related to progesterone-induced smooth muscle relaxation (ie, ureteral dilation, valve laxity) that allows bacteria to ascend to the upper urinary tract. ⁵ Therefore, all pregnant patients are screened for ASB at the initial prenatal visit. Patients whose screening urine cultures are positive require antibiotic therapy (Choice D). The most common pathogen is Escherichia coli, as in this patient. First-line antibiotic therapy includes cephalexin, amoxicillin-clavulanate, or nitrofurantoin. A repeat urine culture (ie, test of cure) is performed after antibiotic completion to ensure clearance of the bacteriuria. (Choice B) Fluoroquinolones (eg, ciprofloxacin) are contraindicated in pregnancy due to the potential association with fetal bone deformities and arthropathy. (Choice C) Doxycycline and other tetracycline antibiotics are contraindicated in pregnancy because they interfere with fetal bone and tooth development. Children exposed to tetracycline in utero can also develop gray discoloration of the teeth. (Choice E) Trimethoprim-sulfamethoxazole is safe in the second trimester but contraindicated in the first (eg, 10 weeks) because it interferes with folic acid metabolism, which is critical to early fetal development. It is also contraindicated in the third trimester due to the risk of neonatal kernicterus. Educational objective: All pregnant patients are screened and treated for asymptomatic bacteriuria at the initial prenatal visit due to the risk of acute pyelonephritis and complications (eg, preterm delivery, low birth weight) associated with untreated asymptomatic bacteriuria. The most common pathogen is Escherichia coli. First-line antibiotics include cephalexin, amoxicillin-clavulanate, or nitrofurantoin. References: Asymptomatic bacteriuria in pregnancy. (http://www.ncbi.nlm.nih.gov/pubmed/17347050) Urinary tract infection and bacteriuria in pregnancy. (http://www.ncbi.nlm.nih.gov/pubmed/26475951)

A 38-Year-Old Woman, Gravida 5 Para 4, at 10 Weeks