Do we treat Enterococcus species and Group B Streptococcus (GBS) in urine with a colony count of 10-100 Colony-Forming Units per Milliliter (CFU/mL) in a non-pregnant patient?

Treatment of Low Colony Count Enterococcus and GBS in Non-Pregnant Patients

No, you should not treat Enterococcus species or Group B Streptococcus with colony counts of 10-100 CFU/mL in non-pregnant patients unless they are symptomatic or have underlying urinary tract abnormalities. 1, 2

Critical Distinction: Pregnancy vs. Non-Pregnancy

The management of GBS bacteriuria is fundamentally different between pregnant and non-pregnant patients 1:

• In pregnancy: All GBS bacteriuria at ANY concentration (even <10³ CFU/mL) requires intrapartum antibiotic prophylaxis during labor due to risk of early-onset neonatal disease 3, 2
• In non-pregnancy: Treat only if symptomatic or structural urinary tract abnormalities are present 1, 2

When to Treat in Non-Pregnant Patients

Treat if the patient has:

• Symptomatic UTI (dysuria, frequency, urgency, fever, flank pain) 1, 4
• Abnormal urinalysis showing pyuria, hematuria, or positive leukocyte esterase 1
• Known underlying urinary tract abnormalities (60% of non-pregnant adults with GBS bacteriuria have structural problems) 4
• Chronic renal failure or other significant comorbidities 4

Do NOT treat if:

• Patient is asymptomatic 1
• Urinalysis is normal 1
• No underlying urinary tract abnormalities 1

Evidence Against Treating Asymptomatic Bacteriuria

The 2019 IDSA guidelines provide strong evidence against screening for or treating asymptomatic bacteriuria in most non-pregnant populations, including patients with diabetes, long-term care residents, and those with indwelling catheters 1. This principle applies equally to GBS-specific asymptomatic bacteriuria 1.

Colony Count Considerations

Your specific scenario of 10-100 CFU/mL is below even the traditional threshold of 10⁵ CFU/mL for significant bacteriuria 5:

• Research shows that even at ≥10⁵ CFU/mL, one-third of patients with GBS in voided urine had contamination only with no true bacteriuria on suprapubic aspiration 5
• At 10-100 CFU/mL, this likely represents colonization or contamination rather than true infection 5
• Laboratories typically report GBS in urine when present at concentrations ≥10⁴ CFU/mL for non-pregnant patients 2

Risks of Unnecessary Treatment

Treating asymptomatic bacteriuria leads to 1:

• Unnecessary antibiotic exposure and resistance development
• Potential adverse drug effects without clinical benefit
• False reassurance that symptoms have been addressed when the true cause remains unidentified

Clinical Pitfall to Avoid

Do not extrapolate pregnancy guidelines to non-pregnant patients. The CDC guidelines mandating treatment of all GBS bacteriuria during pregnancy exist specifically to prevent neonatal disease and do not apply to non-pregnant individuals 3, 1.

When GBS/Enterococcus Treatment IS Indicated

If the patient develops symptomatic UTI, first-line treatment options include 6, 1:

• Penicillin G 500 mg orally every 6-8 hours for 7-10 days (preferred for GBS)
• Ampicillin 500 mg orally every 8 hours for 7-10 days (acceptable alternative)
• For penicillin allergy: Clindamycin 300-450 mg orally every 8 hours (requires susceptibility testing as ~20% of GBS isolates are resistant) 6, 1

Recommended Action

For your patient with 10-100 CFU/mL of Enterococcus or GBS:

1. Assess for symptoms of UTI 1
2. Review urinalysis results 1
3. If asymptomatic with normal urinalysis: No treatment indicated 1
4. If symptomatic or abnormal urinalysis: Treat according to standard UTI protocols 1, 2
5. Consider evaluation for underlying urinary tract abnormalities if GBS is confirmed at higher colony counts 4