What is the treatment for a patient with Group B Streptococcus (GBS) in their urine and concerns about kidney disease?

Treatment of Group B Streptococcus (GBS) in Urine with Kidney Disease Concerns

For patients with Group B Streptococcus (GBS) in urine and kidney disease concerns, appropriate antibiotic treatment should be provided only if the patient is symptomatic or has specific risk factors, while asymptomatic bacteriuria generally should not be treated.

Diagnosis and Assessment

• GBS in urine should be reported by laboratories when present at concentrations of ≥10⁴ colony-forming units/ml in pure culture or mixed with a second microorganism 1
• Determine if the patient has asymptomatic bacteriuria (ASB) or symptomatic urinary tract infection (UTI) 1
• Assess for kidney disease severity by measuring serum creatinine, eGFR, and urinalysis for proteinuria and hematuria 1
• Evaluate for risk factors including pregnancy, advanced age, diabetes mellitus, and liver disease which are associated with higher risk of complications 2

Treatment Algorithm for GBS in Urine

Symptomatic UTI with GBS

• First-line treatment: Penicillin remains the agent of choice for GBS infections 1
• Alternative treatment: Ampicillin is an acceptable alternative to penicillin 1
• For patients with penicillin allergy:
  • If no history of anaphylaxis: First-generation cephalosporins may be used 1
  • If history of anaphylaxis: Perform antimicrobial susceptibility testing and consider clindamycin or vancomycin 1, 2
• Adjust antibiotic dosing based on kidney function 1

Asymptomatic Bacteriuria (ASB) with GBS

• In most adults with kidney disease and ASB: Do not treat with antibiotics 1
• Exceptions where treatment of ASB is recommended:
  • Pregnant women 1
  • Patients who will undergo urologic procedures associated with mucosal trauma 1

Special Considerations for Kidney Disease

• Monitor kidney function closely during and after treatment 1
• Be aware that erythromycin (39.5%) and clindamycin (26.4%) resistance is common in GBS isolates 3
• For patients with advanced CKD, severe tubulointerstitial fibrosis, or small kidney size, avoid nephrotoxic agents 1
• If post-streptococcal glomerulonephritis (PSGN) is suspected:
  • Treat with penicillin (or erythromycin if penicillin-allergic) to decrease antigenic load 1, 4
  • Provide supportive care with diuretics, antihypertensives, and sodium restriction 4
  • Consider corticosteroids only for severe crescentic disease based on anecdotal evidence 1, 4

Monitoring and Follow-up

• Regular assessment of kidney function, blood pressure, proteinuria, and hematuria 1, 4
• Monitor for adverse effects of diuretics including hyponatremia, hypokalemia, and volume depletion 4
• Follow-up urine culture may be considered to confirm resolution of infection in symptomatic cases, but is not necessary for treated ASB 1

Common Pitfalls to Avoid

• Do not treat asymptomatic bacteriuria in most non-pregnant adults, as this increases antimicrobial resistance without clinical benefit 1
• Do not use macrolides empirically for treatment of patients with penicillin allergies due to increasing resistance 3, 2
• Avoid antimicrobial prophylaxis for recurrent UTI without appropriate indications 1
• Do not assume all GBS in urine represents infection; distinguish between colonization and true infection 3, 5