Amoxicillin Dosing for Group B Streptococcal UTI
For Group B streptococcal urinary tract infections, amoxicillin 500 mg orally every 8 hours for 7-10 days is the recommended treatment regimen. 1
Dosing Recommendations
- Amoxicillin 500 mg orally every 8 hours is the standard dose for treating Group B streptococcal UTIs in adults 1
- Treatment should be continued for a minimum of 7-10 days to ensure complete eradication of the infection 1
- For severe infections, the dose may be increased to 875 mg orally every 12 hours or 500 mg every 8 hours 1
- Treatment should continue for at least 48 to 72 hours beyond symptom resolution 1
Alternative Options for Penicillin-Allergic Patients
- For patients with non-severe penicillin allergy: cefazolin 2 g IV initially, then 1 g IV every 8 hours until delivery (for pregnant women) or cephalexin for non-pregnant patients 2
- For patients with severe penicillin allergy (high risk for anaphylaxis): clindamycin 900 mg IV every 8 hours or vancomycin 1 g IV every 12 hours 2
- For uncomplicated UTIs in penicillin-allergic patients: nitrofurantoin 100 mg orally every 6 hours 2, 3
Special Considerations
- Group B streptococci remain highly susceptible to penicillins, making amoxicillin an excellent first-line choice 3
- For pregnant women with GBS UTI, treatment is essential as it represents heavy colonization that increases risk of neonatal infection 2, 4
- In patients with renal impairment (GFR 10-30 mL/min), reduce dosage to 500 mg or 250 mg every 12 hours depending on infection severity 1
- For patients with GFR less than 10 mL/min, reduce to 500 mg or 250 mg every 24 hours 1
Monitoring and Follow-up
- No routine follow-up urine culture is required if symptoms resolve completely 5
- If symptoms persist after completion of treatment, obtain a urine culture to check for treatment failure or reinfection 5
Common Pitfalls to Avoid
- Underdosing or premature discontinuation of therapy may lead to treatment failure or recurrence 5
- Antimicrobial agents should not be used to treat asymptomatic GBS colonization outside of pregnancy, as this is not effective in eliminating carriage and may cause adverse consequences 2
- Failure to consider local resistance patterns when selecting empiric therapy could lead to treatment failure 6
- Using fluoroquinolones as first-line therapy for GBS UTI should be avoided due to increasing resistance and to preserve these agents for more resistant pathogens 6, 3