Treatment Duration for Group B Streptococcus Urinary Tract Infection with Amoxicillin
For uncomplicated Group B Streptococcus (GBS) urinary tract infection, treat with amoxicillin 500 mg orally every 8 hours for 3-7 days. 1
Rationale and Evidence
Uncomplicated UTI Treatment Duration
The most recent guideline evidence specifically addressing GBS in urine recommends 3-7 days for uncomplicated urinary tract infections caused by vancomycin-resistant Enterococci (VRE), which includes streptococcal species 1. This same guideline framework applies to GBS urinary infections, as both are gram-positive cocci with similar treatment considerations.
Key dosing for amoxicillin:
Complicated UTI Considerations
If the infection is complicated (presence of obstruction, foreign body, incomplete voiding, immunosuppression, or systemic symptoms), extend treatment to 5-7 days 1. Complicated UTIs require:
- Longer duration due to difficulty eradicating infection 1
- Consideration of underlying anatomical or functional abnormalities 1
- Assessment for source control 1
Special Circumstances Requiring Longer Treatment
Extend to 7-14 days if:
- Male patient (to exclude prostatitis) 1
- Delayed clinical response or persistent fever beyond 48-72 hours 1
- Catheter-associated infection with catheter remaining in place 1
- Bacteremia from urinary source (7 days minimum once source controlled) 1
GBS Bacteriuria in Pregnancy
Critical exception: Any quantity of GBS bacteriuria during pregnancy requires treatment at diagnosis PLUS intrapartum prophylaxis 1. The pregnant patient should receive:
- Standard UTI treatment at time of diagnosis 1
- Intrapartum chemoprophylaxis (penicillin G 5 million units IV initial dose, then 2.5 million units IV every 4 hours until delivery) 1
- No additional vaginal/rectal screening at 35-37 weeks needed 1
Clinical Pitfalls to Avoid
Do NOT treat asymptomatic bacteriuria in non-pregnant patients, even if GBS is isolated 1. This represents low-value care and promotes antimicrobial resistance without clinical benefit 1.
Do NOT use single-dose therapy for any GBS UTI, as streptococcal infections require sustained antibiotic exposure for eradication 2, 3.
Do NOT extend treatment beyond 7 days for uncomplicated infections with prompt clinical response, as this increases adverse effects and resistance without improving outcomes 1.
Monitoring Response
Patients should demonstrate:
- Defervescence within 72 hours 1
- Symptom resolution within 48 hours for uncomplicated cystitis 1
- Negative urine culture if obtained 5-9 days post-treatment 2, 4
If fever persists beyond 72 hours, consider urologic evaluation and extend treatment duration 1.