Treatment of Group B Streptococcus Urinary Tract Infections

Treatment Approach Based on Pregnancy Status

The Centers for Disease Control and Prevention recommends that any concentration of GBS in urine during pregnancy requires intrapartum antibiotic prophylaxis during labor, regardless of colony count, due to the increased risk of early-onset neonatal disease 1
GBS bacteriuria at any point in pregnancy is a marker for heavy genital tract colonization and increases risk for early-onset neonatal disease, with a recommended approach of intrapartum antibiotic prophylaxis for ≥4 hours before delivery, which is 78% effective in preventing early-onset GBS disease 1, 2

The American College of Obstetricians and Gynecologists recommends penicillin G as the preferred first-line treatment for GBS UTI, with ampicillin as an acceptable alternative, at a dosage of 500 mg orally every 6-8 hours for 7-10 days 3, 4
For severe infections requiring IV therapy, penicillin G 5 million units IV initially, then 2.5 million units IV every 4 hours is recommended, with approximately 20% of GBS isolates resistant to clindamycin, making susceptibility testing mandatory before use 5

The Centers for Disease Control and Prevention warns that underdosing or premature discontinuation of antibiotic treatment leads to treatment failure and recurrence, and using clindamycin without susceptibility testing risks treatment failure due to resistance 3, 5
Treating asymptomatic GBS bacteriuria in non-pregnant patients is unnecessary and promotes antibiotic resistance, according to the Centers for Disease Control and Prevention 4
Failing to provide intrapartum prophylaxis to pregnant women with any GBS bacteriuria increases neonatal mortality risk, with a recommended approach of intrapartum antibiotic prophylaxis for ≥4 hours before delivery 1

The Centers for Disease Control and Prevention recommends intrapartum antibiotic prophylaxis during labor for pregnant women with any concentration of GBS bacteriuria, with a regimen of penicillin G 5 million units IV initially, then 2.5-3.0 million units IV every 4 hours until delivery, or ampicillin 2 g IV initially, then 1 g IV every 4 hours until delivery, which is 78% effective in preventing early-onset GBS disease 6, 7

For patients with penicillin allergy who do not have a history of anaphylaxis, the Centers for Disease Control and Prevention recommends cefazolin dosing: 2 g IV initial dose, then 1 g IV every 8 hours for intrapartum prophylaxis 6
For patients at high risk for anaphylaxis, the Centers for Disease Control and Prevention recommends clindamycin if the GBS isolate is confirmed susceptible, with a dosing of 900 mg IV every 8 hours for intrapartum prophylaxis, or 300-450 mg orally every 6 hours for UTI treatment 6, 7

The American Academy of Family Physicians recommends testing for inducible clindamycin resistance for isolates that are susceptible to clindamycin but resistant to erythromycin, as resistance to erythromycin is often but not always associated with clindamycin resistance 7

The narrow spectrum and proven efficacy of penicillin make it superior to broader-spectrum agents that promote antibiotic resistance, according to the Clinical Infectious Diseases guideline 8
Never use nitrofurantoin, fluoroquinolones, sulfonamides, or tetracyclines for GBS infections, as they lack proven efficacy and are not recommended in any guidelines, as stated in Clinical Infectious Diseases 8