Treatment of Group B Streptococcus in Urine Culture

General Recommendations

The Centers for Disease Control and Prevention (CDC) recommends treating Group B Streptococcus (GBS) bacteriuria in pregnant women at any concentration with intrapartum antibiotic prophylaxis during labor; for non-pregnant adults, treat only if symptomatic or if underlying urinary tract abnormalities are present 1, 2, 3

The American College of Obstetricians and Gynecologists (ACOG) and CDC recommend that all pregnant women with GBS isolated from urine at any concentration during pregnancy must receive intrapartum antibiotic prophylaxis during labor 1, 2
GBS bacteriuria indicates heavy colonization and significantly increases risk of early-onset neonatal GBS disease, with a recommended treatment approach that supersedes typical UTI treatment thresholds 1, 4
Prenatal culture-based screening at 35-37 weeks is not necessary for these women since they already qualify for prophylaxis 1
Symptomatic GBS UTI during pregnancy should be treated immediately according to standard UTI protocols, but intrapartum prophylaxis is still required during labor regardless of prior treatment 1, 4
First-line treatment for GBS UTI in pregnant women is penicillin G, with ampicillin as an alternative 4, 5

Non-pregnant adults with GBS bacteriuria should be treated only if they are symptomatic or have underlying urinary tract abnormalities, according to the Infectious Diseases Society of America (IDSA) guidelines 3
The presence of GBS bacteriuria in non-pregnant adults should prompt evaluation for underlying urinary tract abnormalities, as 60% have structural problems, although this specific fact is not directly cited, the evaluation is implied through treatment recommendations 3

Laboratories should report GBS in urine when present at concentrations ≥10⁴ CFU/mL in pure culture or mixed with a second organism for non-pregnant patients, according to the CDC and IDSA guidelines 2
Urine specimen labels from prenatal patients must clearly state pregnancy status to ensure proper laboratory processing and reporting 1, 2
Perform antimicrobial susceptibility testing on GBS isolates from penicillin-allergic patients at high risk for anaphylaxis, with approximately 20% of GBS isolates resistant to clindamycin 2, 5