Treatment of Group B Streptococcal UTI in a 12-Week Pregnant Female
For a pregnant woman with a Group B Streptococcal (GBS) urinary tract infection at 12 weeks gestation, penicillin G or ampicillin is the recommended first-line treatment due to their narrow spectrum of activity and high efficacy against GBS. 1
First-Line Treatment Options
- Penicillin G (5 million units IV initially, then 2.5 million units IV every 4 hours) is the preferred agent for inpatient treatment due to its narrow spectrum of activity 2
- Ampicillin (2 g IV initial dose, then 1 g IV every 4 hours) is an acceptable alternative for inpatient treatment 2
- For outpatient treatment of uncomplicated GBS UTI, oral amoxicillin is appropriate 3
- Complete the full prescribed course of antibiotics to ensure complete eradication and prevent recurrence 1
Treatment for Penicillin-Allergic Patients
- For patients with penicillin allergy who are not at high risk for anaphylaxis (no history of immediate hypersensitivity reactions), cefazolin (2 g IV initial dose, then 1 g IV every 8 hours) is the preferred alternative 2
- For patients at high risk for anaphylaxis (history of anaphylaxis, angioedema, respiratory distress, or urticaria with penicillin), clindamycin (900 mg IV every 8 hours) can be used if the isolate is confirmed susceptible 2
- If susceptibility testing is not available or the isolate is resistant to clindamycin, vancomycin (1 g IV every 12 hours) is recommended 2
Special Considerations for GBS in Pregnancy
- Women with GBS bacteriuria in any concentration during pregnancy should receive intrapartum antimicrobial prophylaxis during labor to prevent early-onset neonatal GBS disease 1
- The presence of GBS in urine during pregnancy is associated with higher risk of preterm labor, and treatment has been shown to reduce this risk 4
- All pregnant women should be screened for bacteriuria, including GBS, and subsequently treated with appropriate antibiotics 5
Importance of Susceptibility Testing
- Susceptibility testing should be performed on GBS isolates from penicillin-allergic patients at high risk for anaphylaxis 1
- Testing for inducible clindamycin resistance is necessary for isolates that are susceptible to clindamycin but resistant to erythromycin 6
- GBS isolates remain highly susceptible to penicillin and first-generation cephalosporins, but approximately 5% show resistance to clindamycin 7
Follow-up and Monitoring
- A repeat urine culture should be performed approximately one week after completing treatment to confirm eradication 3
- Women with GBS bacteriuria during pregnancy should still receive intrapartum antibiotic prophylaxis during labor regardless of whether they were treated earlier in pregnancy 2
- If GBS is detected in urine at ≥104 colony-forming units/ml, laboratories should report this finding as it indicates heavy colonization 2
Clinical Pitfalls and Caveats
- Underdosing or premature discontinuation of therapy may lead to treatment failure or recurrence 1
- Ampicillin should not be used for asymptomatic bacteriuria due to high rates of resistance among other urinary pathogens, but remains effective against GBS 5
- Failure to provide intrapartum prophylaxis to women with previous GBS bacteriuria in pregnancy can increase the risk of early-onset neonatal GBS disease 2