What is the recommended treatment for a Group B strep (Streptococcus agalactiae) urinary tract infection (UTI) in the first trimester of pregnancy?

Treatment of Group B Streptococcus UTI in First Trimester of Pregnancy

Women with Group B Streptococcus (GBS) urinary tract infection during the first trimester of pregnancy should be treated according to current standards of care for urinary tract infection during pregnancy AND should receive intrapartum antibiotic prophylaxis during labor to prevent early-onset GBS disease in the newborn. 1

Immediate Treatment of GBS UTI in Pregnancy

Treatment Approach

• GBS UTI during pregnancy requires prompt treatment regardless of whether it is symptomatic or asymptomatic 1, 2
• Treatment should follow standard UTI treatment protocols for pregnancy, with antibiotics that are safe during the first trimester 1, 3
• All GBS isolates from urine should be treated regardless of colony count, as GBS bacteriuria is a marker for heavy genital tract colonization 1

Recommended Antibiotics for GBS UTI in Pregnancy

• First-line options:

  • Penicillin or ampicillin (all GBS strains remain fully sensitive to these antibiotics) 4
  • Cephalexin or other first-generation cephalosporins 3, 5
  • Nitrofurantoin (except near term) 3

• For penicillin-allergic patients:

  • For patients without anaphylaxis history: cefazolin 1
  • For patients with high risk of anaphylaxis: clindamycin or erythromycin if the strain is susceptible; vancomycin if susceptibility is unknown or resistance is present 1

Important Clinical Considerations

• Ampicillin should not be used as first-line therapy for other UTIs due to high resistance rates with E. coli, but remains effective against GBS 3, 5
• Antibiotic susceptibility testing should be performed, especially for penicillin-allergic patients, as high resistance rates to clindamycin (77.34%) and tetracycline (88.46%) have been reported 4
• GBS bacteriuria is associated with increased risk for early-onset neonatal GBS disease 1

Follow-up and Long-term Management

Post-treatment Follow-up

• A test of cure (repeat urine culture) should be performed after completion of antibiotic therapy 3
• Recurrent GBS UTIs during pregnancy may require prophylactic antibiotics 3, 5

Intrapartum Management

• All women with GBS bacteriuria at any point during the current pregnancy must receive intrapartum antibiotic prophylaxis during labor 1
• These women do not need additional GBS screening at 35-37 weeks' gestation 1

Intrapartum Antibiotic Prophylaxis Regimens

• For women without penicillin allergy:

  • Penicillin G: 5 million units IV initial dose, then 2.5 million units IV every 4 hours until delivery 1
  • Alternative: Ampicillin 2g IV initial dose, then 1g IV every 4 hours until delivery 1

• For women with penicillin allergy:

  • Without history of anaphylaxis: Cefazolin 2g IV initial dose, then 1g IV every 8 hours until delivery 1
  • With history of anaphylaxis and susceptible GBS: Clindamycin 900mg IV every 8 hours until delivery 1
  • With history of anaphylaxis and unknown susceptibility or resistant GBS: Vancomycin 1g IV every 12 hours until delivery 1

Common Pitfalls and Caveats

• Do not attempt to eradicate GBS colonization before labor with antibiotics, as this is ineffective and may cause adverse consequences 1
• Do not withhold intrapartum prophylaxis for women with history of GBS bacteriuria in the current pregnancy, even if subsequent cultures are negative 1
• Do not confuse GBS bacteriuria management with that of other UTI pathogens; GBS requires specific attention due to neonatal risks 1
• Intrapartum prophylaxis is not needed if cesarean delivery is performed before onset of labor on a woman with intact amniotic membranes, regardless of GBS status 1
• Topical treatments (such as intravaginal clindamycin) are not recommended for GBS UTI treatment, though they may have a role in vaginal colonization 6