Treatment of Group B Streptococcus Urinary Tract Infections
For Group B Streptococcus (GBS) urinary tract infections, the recommended first-line treatment is amoxicillin 500 mg orally every 8 hours for 7-10 days. 1
First-Line Treatment Options
- Amoxicillin: 500 mg orally every 8 hours for 7-10 days 1, 2
- Penicillin: Alternative option if amoxicillin is unavailable 3
Alternative Options for Penicillin-Allergic Patients
Non-severe penicillin allergy:
- Cefazolin: 1-2 g IV every 8 hours (if parenteral therapy needed)
- Cephalexin: 500 mg orally every 6 hours 1
Severe penicillin allergy:
Treatment Considerations
Antibiotic Susceptibility
Recent research shows that GBS strains remain highly susceptible to penicillins, with studies demonstrating 100% sensitivity to penicillin and ampicillin 4. However, high resistance rates have been observed for clindamycin (77.34%) and tetracycline (88.46%) 4.
Duration of Treatment
The standard duration of therapy for uncomplicated GBS UTI is 7-10 days 1. Treatment should be discontinued within 24 hours after symptoms resolve to prevent resistance development.
Special Populations
Pregnant Women
- GBS bacteriuria in pregnancy requires both treatment at diagnosis AND intrapartum prophylaxis during labor 1
- For intrapartum prophylaxis:
- Penicillin G: 5 million units IV initial dose, then 2.5-3.0 million units IV every 4 hours until delivery
- Ampicillin: 2 g IV initial dose, then 1 g IV every 4 hours until delivery 1
Follow-up Recommendations
- Repeat urine culture 7 days after completing therapy to confirm eradication 5
- For women with GBS bacteriuria, no re-screening is necessary in the third trimester as they are presumed to be GBS colonized 6
Clinical Pearls and Pitfalls
- GBS bacteriuria at any colony count in pregnant women requires treatment due to risk of neonatal GBS disease 6
- In non-pregnant adults, GBS bacteriuria does not require special prophylaxis beyond standard UTI treatment 1
- For recurrent GBS UTIs in women, consider evaluating for vaginal colonization as a potential reservoir for reinfection 7
- Asymptomatic bacteriuria with GBS should be treated with the same regimen as symptomatic infections 1
Antimicrobial therapy should be guided by local resistance patterns and patient-specific factors such as allergies, pregnancy status, and renal function.