What is the recommended treatment for Group B strep (Streptococcus agalactiae) urinary tract infection (UTI)?

Treatment of Group B Streptococcal Urinary Tract Infection

Penicillin is the preferred first-line treatment for Group B Streptococcal (GBS) urinary tract infections due to its narrow spectrum of activity and high efficacy. 1

First-Line Treatment Options

• For non-allergic patients with GBS UTI, penicillin G is the preferred agent (5 million units IV initially, then 2.5 million units IV every 4 hours for inpatient cases) 2
• For outpatient treatment of uncomplicated GBS UTI, oral penicillin or ampicillin is recommended for a 7-day course 1, 3
• Ampicillin (2g IV initially, then 1g IV every 4 hours) is an acceptable alternative to penicillin G, though penicillin is preferred due to its narrower spectrum 2
• 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, cefazolin (2g IV initially, then 1g IV every 8 hours) is the preferred alternative 2, 1
• For patients at high risk for anaphylaxis (history of immediate hypersensitivity reactions), treatment options include: 2
  • Clindamycin 900mg IV every 8 hours (only if the isolate is confirmed susceptible)
  • Vancomycin 1g IV every 12 hours (for severe infections or when susceptibility results are unavailable)

Importance of Susceptibility Testing

• Susceptibility testing should be performed on all GBS isolates from penicillin-allergic patients at high risk for anaphylaxis 2, 1
• Testing for inducible clindamycin resistance is necessary for isolates that are susceptible to clindamycin but resistant to erythromycin 1
• Recent studies show increasing resistance rates to certain antibiotics among GBS isolates: erythromycin (36.3-44.5%), clindamycin (18-26%), and tetracycline (81.5%) 4, 5
• No penicillin-resistant GBS strains have been identified in recent studies, maintaining penicillin as the drug of choice 6

Special Considerations

Pregnant Women

• Women with GBS bacteriuria in any concentration during pregnancy should receive intrapartum antimicrobial prophylaxis during labor to prevent early-onset neonatal GBS disease 1
• In the absence of GBS urinary tract infection, antimicrobial agents should not be used before the intrapartum period to treat asymptomatic GBS colonization 2

Complicated UTIs

• For complicated UTIs due to carbapenem-resistant Enterobacterales (which may include GBS), options include ceftazidime-avibactam, meropenem-vaborbactam, or imipenem-cilastatin-relebactam 2
• For recurrent GBS UTIs, evaluate for underlying urological abnormalities and implement behavioral modifications (adequate hydration, voiding after intercourse) 3

Follow-Up and Monitoring

• Obtain a follow-up urine culture 1-2 weeks after completing treatment to confirm eradication 3
• Document resolution of symptoms (dysuria, frequency, urgency) to ensure clinical cure 3
• If symptoms persist despite appropriate antibiotic therapy, consider imaging studies to rule out complications or anatomical abnormalities 3

Clinical Pitfalls and Caveats

• Underdosing or premature discontinuation of therapy may lead to treatment failure or recurrence 1
• Failure to consider local resistance patterns when selecting empiric therapy could lead to treatment failure 1
• GBS UTIs are associated with underlying diseases in men and non-pregnant women, particularly diabetes mellitus, which should be evaluated and managed 6
• Fluoroquinolone resistance is increasing among GBS isolates (12.8% in some studies), especially in men and non-pregnant women, so these should not be used as first-line agents 6