Do I need to treat a Group B Streptococcus (Streptococcus agalactiae) urinary tract infection in a non‑pregnant woman?

Treatment of Group B Streptococcus UTI in Non-Pregnant Women

In non-pregnant women, treat Group B Streptococcus urinary tract infection only if the patient has urinary symptoms (dysuria, frequency, urgency, suprapubic pain) or systemic signs of infection; asymptomatic bacteriuria with GBS should not be treated. 1

Critical Distinction: Pregnancy Status Determines Management

The management of GBS bacteriuria is fundamentally different between pregnant and non-pregnant patients:

Non-Pregnant Women (Your Patient)

• Do not treat asymptomatic bacteriuria – The 2019 IDSA guidelines provide strong evidence against screening for or treating asymptomatic bacteriuria in non-pregnant populations, with this principle applying specifically to GBS-specific asymptomatic bacteriuria 1

• Treat only symptomatic UTI – Treatment is appropriate only when the patient has classic urinary symptoms (dysuria, frequency, urgency, suprapubic pain, flank tenderness) or systemic signs of infection (fever, rigors, hemodynamic instability) 1

• Avoid unnecessary antibiotics – Treating asymptomatic bacteriuria leads to unnecessary antibiotic exposure, resistance development, potential adverse drug effects without clinical benefit, and false reassurance when symptoms have an alternative cause 1

Pregnant Women (For Comparison)

• Always treat any concentration of GBS in urine – Any detection of GBS bacteriuria during pregnancy mandates immediate treatment plus intrapartum IV prophylaxis during labor, regardless of symptoms or colony count 1, 2

• Risk to neonate drives treatment – GBS bacteriuria indicates heavy genital tract colonization and increases the risk of early-onset neonatal disease by more than 25-fold 3

When Treatment IS Indicated in Non-Pregnant Women

Treat GBS UTI in non-pregnant women when:

• Patient has symptomatic UTI with dysuria, frequency, urgency, or suprapubic pain 1
• Patient has systemic signs of infection (fever, rigors, hemodynamic instability) 1
• Patient has underlying urinary tract abnormalities 1, 3
• Patient is scheduled for endoscopic urologic procedure involving mucosal trauma 1

Recommended Antibiotic Regimens (When Treatment Is Indicated)

First-Line Treatment

• Penicillin G 500 mg orally every 6-8 hours for 7-10 days – Preferred due to narrow spectrum and universal GBS susceptibility 1

• Ampicillin 500 mg orally every 8 hours for 7-10 days – Acceptable alternative 1

Penicillin-Allergic Patients

• Clindamycin 300-450 mg orally every 8 hours – Requires susceptibility testing before use due to 13-25% resistance rates 1, 2

• Cephalothin (first-generation cephalosporin) – Shows 100% susceptibility among GBS isolates 1

Complicated Infections

• Consider 14-day treatment duration when prostatitis cannot be excluded in men or for complicated infections 1

• Initial IV therapy with ampicillin 2 g IV every 4-6 hours for patients with systemic symptoms, then transition to oral therapy once clinically stable 1

• Combination therapy with ampicillin plus aminoglycoside for severe presentations 1

Clinical Context: GBS as a Urinary Pathogen in Non-Pregnant Adults

• GBS accounts for approximately 2% of positive urine cultures in non-pregnant adults, with 85% occurring in women 4

• Most non-pregnant adults with GBS UTI (95%) have at least one underlying condition, most commonly urinary tract abnormalities (60%) or chronic renal failure (27%) 4

• Among non-pregnant women treated in outpatient settings, GBS UTI occurs mainly in women over 40 years old and causes non-complicated cystitis in more than half of cases 5

• Clinical manifestations are equally distributed between upper and lower urinary tract infections (37% and 38% respectively) 4

Antibiotic Susceptibility

• Universal penicillin susceptibility – All GBS isolates worldwide remain universally susceptible to penicillin and ampicillin; no penicillin-resistant GBS has ever been documented 3

• High resistance to certain agents – GBS shows high resistance to tetracycline (81.6-88.5%) and co-trimoxazole (68.9%) 3

• Variable macrolide/lincosamide resistance – Erythromycin resistance ranges from 7-25%, and clindamycin resistance from 3-15% with significant geographic variation 1, 3

Common Pitfalls to Avoid

• Do not treat nonspecific symptoms alone – Malaise, fatigue, or confusion without urinary symptoms does not justify antibiotic therapy; these symptoms are more often linked to underlying host factors rather than true urinary infection 1

• Do not confuse pregnancy and non-pregnancy guidelines – The CDC mandate to treat all GBS bacteriuria applies specifically to pregnant women to prevent neonatal disease and should not be applied to non-pregnant patients 1

• Screen for urinary tract abnormalities – GBS bacteriuria in non-pregnant adults signals a need for screening for underlying urinary tract abnormalities, as 60% have structural problems 4

• Evaluate alternative causes – When patients present with only nonspecific symptoms, evaluate for dehydration, electrolyte disturbances, anemia, thyroid dysfunction, depression, and medication side effects rather than prescribing antibiotics 1

Follow-Up Considerations

• Follow-up urine culture after treatment completion may be warranted to ensure eradication, especially in patients with recurrent UTIs 1

• Poor clinical outcome occurred in 18% of episodes despite treatment in one series, emphasizing the importance of identifying underlying urinary tract abnormalities 4