What is the recommended treatment for Streptococcus agalactiae (Group B Streptococcus, GBS) in urine, particularly in pregnant women?

Treatment of Streptococcus agalactiae (Group B Streptococcus) in Urine

Pregnant women with any colony count of Group B Streptococcus (GBS) in urine should receive appropriate antibiotic treatment for urinary tract infection during pregnancy, followed by intrapartum antibiotic prophylaxis during labor regardless of previous treatment. 1, 2

Treatment Recommendations for GBS in Urine

For Pregnant Women:

1. Initial UTI Treatment:

   • Treat symptomatic or asymptomatic GBS urinary tract infection according to standard UTI treatment protocols 1
   • First-line options:
     • Penicillin G (5 million units IV initial dose, then 2.5-3.0 million units IV every 4 hours)
     • Ampicillin (2 g IV initial dose, then 1 g IV every 4 hours) 2
   • For oral outpatient treatment:
     • Amoxicillin or appropriate oral penicillin for 5-7 days 2

2. Intrapartum Prophylaxis:

   • All pregnant women with GBS bacteriuria at any point during pregnancy require intrapartum antibiotic prophylaxis during labor 1, 2
   • First-line prophylaxis:
     • Penicillin G: 5 million units IV initial dose, then 2.5-3.0 million units IV every 4 hours until delivery
     • Ampicillin: 2 g IV initial dose, then 1 g IV every 4 hours until delivery 2
   • For penicillin-allergic patients:
     • Non-anaphylactic reactions: Cefazolin 2 g IV initial dose, then 1 g IV every 8 hours
     • Anaphylactic reactions: Clindamycin 900 mg IV every 8 hours (if susceptible) or vancomycin 1 g IV every 12 hours 2

For Non-Pregnant Patients:

• Standard UTI treatment for 5-7 days for uncomplicated UTIs 2
• 10-14 days for complicated UTIs or pyelonephritis 2
• First-line: Penicillin-based antibiotics (all GBS isolates remain susceptible to penicillin) 3, 4, 5

Important Clinical Considerations

GBS Bacteriuria in Pregnancy

• GBS is found in the urine of 2-7% of pregnant women 1
• Any colony count of GBS in urine during pregnancy is considered significant and indicates heavy genital tract colonization 1
• GBS bacteriuria is associated with increased risk of early-onset GBS disease in newborns 1
• Antibiotics do not eliminate GBS from genitourinary and gastrointestinal tracts; recolonization after treatment is typical 1, 2

Antimicrobial Susceptibility

• GBS remains universally susceptible to penicillin, making it the drug of choice 3, 4, 5
• Increasing resistance to alternative antibiotics like clindamycin and erythromycin has been observed 3, 4
• Susceptibility testing is essential for penicillin-allergic patients 2

Common Pitfalls to Avoid

1. Failure to recognize significance of any colony count: Even low colony counts (<10⁴ CFU/mL) of GBS in urine during pregnancy should be considered significant 1
2. Assuming treatment during pregnancy eliminates need for intrapartum prophylaxis: Women who received antibiotics for GBS bacteriuria during pregnancy still require intrapartum prophylaxis 1, 2
3. Inappropriate dosing intervals: For penicillin G, the dosing interval should be 4 hours to ensure anti-GBS activity in all patients 6
4. Not testing susceptibility in penicillin-allergic patients: Due to increasing resistance to alternative antibiotics, susceptibility testing is crucial 2, 3

GBS bacteriuria at any point during pregnancy is a recognized risk factor for early-onset GBS disease and requires both appropriate treatment of the UTI and subsequent intrapartum antibiotic prophylaxis to prevent neonatal infection and associated morbidity and mortality.