Should a urine culture growing Streptococcus agalactiae (Group B Streptococcus) at 50,000–100,000 CFU/mL be treated with antibiotics? | Rounds Should a urine culture growing Streptococcus agalactiae (Group B Streptococcus) at 50,000–100,000 CFU/mL be treated with antibiotics? | Rounds

Should a urine culture growing Streptococcus agalactiae (Group B Streptococcus) at 50,000–100,000 CFU/mL be treated with antibiotics?

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Last updated: July 14, 2026 · View editorial policy

Group B Streptococcus Bacteriuria Treatment Thresholds

Antibiotic treatment is generally not recommended for asymptomatic bacteriuria (ASB) in nonpregnant adults. [1] In pregnancy, Group B Streptococcus (GBS) bacteriuria warrants targeted antibiotic treatment when the colony count is ≥100,000 CFU/mL. [2]

Sources (3)

[1] Guideline 2019
Clinical Practice Guideline for the Management of Asymptoma…
Clinical Infectious Diseases (IDSA)
View Source
[2] Guideline 2023
Urinary Tract Infections in Pregnant Individuals
ACOG Clinical Consensus
View Source
[3] Guideline 2020
Prevention of Group B Streptococcal Early-Onset Disease in …
ACOG Committee Opinion
View Source

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