What is the appropriate treatment for a non-pregnant patient with a urinary tract infection caused by Group B Streptococcus?

Treatment of Group B Streptococcus Urinary Tract Infection in Non-Pregnant Patients

For a non-pregnant patient with a urinary tract infection caused by Group B Streptococcus (GBS), penicillin or ampicillin is the first-line treatment of choice. 1

Diagnosis and Clinical Significance

• The urinalysis shows significant findings consistent with UTI: cloudy appearance, trace blood, trace protein, 2+ leukocyte esterase, and many bacteria 2
• The urine culture confirms 50,000-99,000 CFU/mL of Group B Streptococcus, which is a clinically significant finding in a symptomatic non-pregnant patient 3
• GBS accounts for approximately 1-2% of positive urine cultures in non-pregnant adults 3, 4

Treatment Recommendations

First-Line Treatment Options:

• Penicillin G: The preferred agent due to its narrow spectrum of activity 2

  • Dosing: 500 mg orally every 6-8 hours for 7-10 days 5

• Ampicillin: An acceptable alternative to penicillin 2

  • Dosing: 500 mg orally every 8 hours for 7-10 days 6
  • For more severe infections: 875 mg orally every 12 hours 6

For Penicillin-Allergic Patients:

• Clindamycin: 300-450 mg orally every 8 hours 2

  • Note: Susceptibility testing should be performed before using clindamycin due to increasing resistance 2, 7

• Erythromycin: 500 mg orally every 6 hours 2

  • Note: Not recommended for treatment of urinary tract infections as stated in the culture report 1

Duration of Treatment

• Treatment should be continued for 7-10 days 6, 5
• For streptococcal infections, a minimum of 10 days of treatment is recommended to ensure complete eradication 6, 5

Important Clinical Considerations

• Unlike in pregnant women, GBS in urine of non-pregnant patients should only be treated if symptomatic or if there are underlying urinary tract abnormalities 1
• The presence of GBS in urine of non-pregnant adults may signal a need to screen for underlying urinary tract abnormalities, as these are present in up to 60% of cases 3
• Recent studies have shown increasing resistance to antibiotics among GBS isolates, with one study reporting 18.3% resistance to penicillin and 81.6% to ampicillin 7
• Follow-up urine culture after treatment completion may be warranted to ensure eradication, especially in patients with recurrent UTIs 2

Monitoring and Follow-up

• Symptoms should improve within 48-72 hours of starting appropriate antibiotic therapy 6
• If symptoms persist beyond this timeframe, reassessment is necessary to rule out complications or antibiotic resistance 3
• Consider urologic evaluation if this is a recurrent UTI, as GBS UTIs are associated with underlying urinary tract abnormalities 3, 4

Pitfalls to Avoid

• Do not apply the guidelines for pregnant women (which recommend treatment of GBS in urine at any concentration) to non-pregnant patients 1
• Avoid using erythromycin for UTI treatment as it achieves poor urinary concentrations 1
• Do not assume all GBS isolates are susceptible to penicillin, as resistance rates are increasing 7