Treatment of Beta Hemolytic Streptococcus Group B Urinary Tract Infection
Ampicillin is the first-line treatment for Group B Streptococcus (GBS) urinary tract infections, administered at 500 mg orally every 8 hours for 3-7 days for uncomplicated infections. 1
First-Line Treatment Options
- For uncomplicated GBS UTIs in adults, ampicillin 500 mg orally every 8 hours for 3-7 days is the recommended treatment 1, 2
- Alternatively, amoxicillin 500 mg orally every 8 hours can be used with similar efficacy 1
- For complicated UTIs or severe infections, higher doses of ampicillin (up to 18-30 g/day IV in divided doses) may be required 1
- Treatment should continue for a minimum of 48-72 hours after the patient becomes asymptomatic 2
Alternative Treatment Options for Penicillin-Allergic Patients
- For patients with non-severe penicillin allergies, cefazolin 2 g IV initial dose, then 1 g IV every 8 hours until infection resolves 3
- For patients with severe penicillin allergies (history of anaphylaxis, angioedema, or urticaria):
Important Clinical Considerations
- Obtain urine culture before initiating therapy to confirm the diagnosis and guide treatment 1
- Significant bacteriuria is defined as ≥50,000 CFUs/mL of a single urinary pathogen 1
- Beta-lactam antibiotics remain highly effective against GBS, with virtually all isolates showing susceptibility 6, 7
- Resistance to macrolides and clindamycin is increasing, with studies showing inducible MLSB resistance to erythromycin and clindamycin at 23.1% and 10.7% respectively 6
- For complicated or recurrent infections, evaluation for structural abnormalities of the urinary tract may be indicated 1
- Distinguishing between colonization and true infection is important to avoid unnecessary treatment 1
Special Considerations in Pregnancy
- In pregnant patients, fluoroquinolones should be avoided 5
- For GBS UTIs in pregnancy, penicillin G, ampicillin, or cefazolin remain the preferred agents 5
- Consult with an obstetrician for appropriate antibiotic selection in pregnant patients 5
- For pregnant women with GBS colonization approaching delivery, intrapartum antibiotic prophylaxis is recommended to prevent neonatal GBS disease 3
Duration of Therapy
- For uncomplicated UTIs: 3-7 days 1
- For complicated UTIs: 5-7 days 1
- For severe infections or bacteremia: 10-14 days 1
- For infections caused by hemolytic strains of streptococci, a minimum of 10 days' treatment may be recommended to guard against the risk of rheumatic fever or glomerulonephritis 2
Monitoring and Follow-up
- Consider follow-up urine culture after completion of treatment to ensure eradication, especially in complicated cases 1
- In chronic urinary infections, frequent bacteriologic and clinical appraisal may be necessary during therapy and for several months afterwards 2
- Stubborn infections may require treatment for several weeks 2