Management of Group B Streptococcus in Urine

Diagnosis and Initial Management

The Centers for Disease Control and Prevention recommends that women with GBS isolated from the urine in any concentration during pregnancy should receive intrapartum antibiotic prophylaxis because they are heavily colonized with GBS and at increased risk of delivering an infant with early-onset GBS disease 1, 2
GBS bacteriuria during pregnancy is a marker for heavy genital tract colonization and increases the risk for early-onset neonatal GBS disease 1, 3
Laboratories should report GBS in urine culture specimens when present at concentrations of ≥10^4 colony-forming units/ml in pure culture or mixed with a second microorganism 4, 5
Women with symptomatic or asymptomatic GBS urinary tract infection detected during pregnancy should be treated according to current standards of care for urinary tract infection during pregnancy 1, 2

The American College of Obstetricians and Gynecologists recommends that all women with GBS bacteriuria during the current pregnancy should receive intrapartum antibiotic prophylaxis regardless of the concentration of bacteria found in the urine 1, 2
For intrapartum prophylaxis in women without penicillin allergy, the recommended regimen is: penicillin G, 5 million units IV initial dose, then 2.5 million units IV every 4 hours until delivery 6
An alternative regimen is ampicillin, 2 g IV initial dose, then 1 g IV every 4 hours until delivery 6

For women with penicillin allergy who are not at high risk for anaphylaxis: cefazolin, 2 g IV initial dose, then 1 g IV every 8 hours until delivery 6
For women at high risk for anaphylaxis, susceptibility testing for clindamycin and erythromycin should be performed on GBS isolates 4
If the isolate is susceptible to clindamycin: clindamycin, 900 mg IV every 8 hours until delivery 6
If the isolate is resistant to clindamycin or susceptibility is unknown: consult infectious disease specialist for alternative regimens 4, 6

Women with planned cesarean delivery performed before rupture of membranes and onset of labor are at low risk for having an infant with early-onset GBS disease and should not routinely receive intrapartum chemoprophylaxis for GBS disease prevention, regardless of GBS colonization status 1, 7
Women who have previously given birth to an infant with invasive GBS disease should receive intrapartum chemoprophylaxis regardless of current GBS colonization status 1, 2

Failure to report GBS in urine specimens from pregnant women can lead to missed opportunities for intrapartum prophylaxis 3, 5
Urine specimens from pregnant patients should be clearly labeled to indicate pregnancy status to assist laboratory processing and appropriate reporting of results 1, 2
Antibiotics given before the intrapartum period do not eliminate GBS from the genitourinary and gastrointestinal tracts, and recolonization after a course of antibiotics is typical 3
While treating GBS bacteriuria during pregnancy is important, it does not eliminate the need for intrapartum antibiotic prophylaxis 1, 3