Streptococcus agalactiae Infections

Epidemiology and Clinical Significance

The Centers for Disease Control and Prevention (CDC) reports that Group B Streptococcus (GBS) causes 2-4% of urinary tract infections during pregnancy, representing a clinically important pathogen due to its association with heavy genital tract colonization and increased risk of neonatal disease 1, 2
In non-pregnant populations, GBS accounts for approximately 1.79-8.92% of positive urine cultures in women, with higher prevalence in specific age groups 4, 5

Pregnant women: GBS bacteriuria occurs in 2-7% of pregnancies and serves as a marker for heavy genital tract colonization 3
Non-pregnant adults: GBS causes UTIs in males and non-pregnant females, particularly those with underlying conditions such as diabetes mellitus 4, 5

The spectrum of GBS urinary tract infections includes cystitis, pyelonephritis, urosepsis, and asymptomatic bacteriuria, with the gastrointestinal tract serving as the natural reservoir for GBS 4, 5

In pregnant women, any quantity of GBS bacteriuria detected during pregnancy mandates both immediate treatment and intrapartum antibiotic prophylaxis, regardless of symptoms or colony count 1, 2, 3
The CDC recommends that vaginal-rectal screening at 35-37 weeks is not necessary for women with documented GBS bacteriuria 1, 2
In non-pregnant patients, treatment should only be provided for symptomatic UTI or in patients with underlying urinary tract abnormalities, and asymptomatic bacteriuria with GBS should NOT be treated 7