What is the recommended treatment for Group B Streptococcus (GBS) urinary tract infections (UTI) in pregnancy, given that oral treatment is not an option?

Treatment of Group B Streptococcus UTI in Pregnancy When Oral Treatment is Not an Option

For pregnant women with Group B Streptococcus (GBS) urinary tract infection when oral treatment is not an option, intravenous penicillin G (5 million units IV initially, then 2.5 million units IV every 4 hours until delivery) is the recommended treatment of choice. 1

Rationale for Intravenous Treatment

GBS bacteriuria during pregnancy is a significant finding that requires appropriate management for several reasons:

1. It is a marker for heavy genital tract colonization 1
2. It increases risk for:
   • Maternal complications (pyelonephritis, chorioamnionitis)
   • Neonatal GBS disease
   • Preterm labor 2

Treatment Algorithm for GBS UTI in Pregnancy

First-line Treatment (No Penicillin Allergy)

• Penicillin G: 5 million units IV initial dose, then 2.5 million units IV every 4 hours until delivery 1
  • Preferred due to narrow spectrum of activity
  • Dosing interval should be 4 hours to ensure anti-GBS activity 3

Alternative First-line Treatment

• Ampicillin: 2 g IV initial dose, then 1 g IV every 4 hours until delivery 1
  • Effective but broader spectrum than penicillin

For Penicillin-Allergic Patients

• Non-anaphylactic reactions: Cefazolin 2 g IV initial dose, then 1 g IV every 8 hours until delivery 1
• High risk for anaphylaxis:
  • If susceptibility testing available and organism is susceptible:
    • Clindamycin 900 mg IV every 8 hours until delivery, OR
    • Erythromycin 500 mg IV every 6 hours until delivery
  • If susceptibility unknown or organism resistant:
    • Vancomycin 1 g IV every 12 hours until delivery 1

Important Clinical Considerations

1. No oral treatment for GBS colonization: Oral antimicrobial agents should not be used to treat women who are found to be colonized with GBS during prenatal screening. Such treatment is not effective in eliminating carriage or preventing neonatal disease 1

2. GBS bacteriuria at any concentration is significant:

   • Women with any quantity of GBS bacteriuria during pregnancy should receive intrapartum chemoprophylaxis 4
   • No need for repeat screening by genital tract culture or urinary culture in the third trimester, as they are presumed to be GBS colonized 4

3. Duration of treatment:

   • Acute UTI symptoms should be treated with appropriate antibiotics at time of diagnosis
   • Additionally, these women should receive intrapartum prophylaxis during labor or rupture of membranes 4

Pitfalls to Avoid

1. Do not use oral antibiotics for GBS colonization: They are ineffective for eliminating carriage or preventing neonatal disease 1

2. Do not miss intrapartum prophylaxis: Even after treating the acute UTI, intrapartum prophylaxis is still required 4

3. Do not use ampicillin for empiric UTI treatment: High resistance rates to ampicillin among E. coli make it a poor choice for empiric UTI treatment, though it remains effective for GBS 5

4. Do not repeat GBS screening: Women with documented GBS bacteriuria should not be re-screened in the third trimester as they are presumed to be GBS colonized 4

5. Do not use antibiotics before intrapartum period for GBS colonization (in the absence of UTI) as this is not effective in eliminating carriage or preventing neonatal disease 1

By following this treatment approach, you can effectively manage GBS UTI in pregnancy when oral treatment is not an option, reducing the risk of maternal and neonatal complications.