Clinical Overview of Group B Strep Disease

Key points

  • Group B Streptococcus (group B strep, GBS) bacteria can cause severe infection in anyone.
  • Certain factors can increase someone's risk.
  • Help prevent early-onset GBS disease through intrapartum antibiotic prophylaxis.
  • No effective strategy has yet been identified for how to prevent late-onset disease or adult disease.
A doctor wearing a white lab coat with a stethoscope around her neck.


Streptococcus agalactiae or GBS cause GBS disease.

Risk factors

Pregnancy related risk factors

The following groups are at increased risk for GBS disease:

  • Pregnant and postpartum women
  • Fetuses
  • Neonates

For neonatal disease, risk is higher among infants born to women with

  • GBS colonization
  • Prolonged rupture of membranes
  • Preterm delivery

Other factors

Other factors that can increase adults' risk of GBS disease include:

  • Age
  • Medical conditions
  • Race


Risk increases with age: Adults 65 years or older are at increased risk compared to adults younger than 65 years old.

Medical conditions

Medical conditions that can increase adults' risk include:

  • Cancer
  • Cardiovascular disease
  • Diabetes mellitus
  • Obesity


Experts do not know why, but disease rates are also substantially higher among African American people.

How it spreads

Asymptomatic carriage in gastrointestinal and genital tracts is common. Intrapartum transmission via ascending spread from the vagina occurs. Mode of transmission of disease in non-pregnant adults is not completely known.

Disease rates and trends

Since its introduction, intrapartum prophylaxis has decreased disease in neonates in the first week of life. However, GBS bacteria remain a leading cause of meningitis and bloodstream infections in neonates younger than 3 months old.

Active surveillance for GBS disease‎

Surveillance for invasive GBS disease is ongoing in a multistate population through Active Bacterial Core surveillance (ABCs).

Clinical features


In neonates, two syndromes exist for GBS disease:

  • Early-onset (<7 days old)
  • Late-onset (7–89 days old)

Both can manifest as bacteremia, sepsis, pneumonia, and meningitis.


Most common manifestations of severe infections in adults are bacteremia (including sepsis) and skin and soft tissue infections.

During pregnancy

Pregnancy-related infections and complications include:

  • Bloodstream infections (including sepsis)
  • Intraamniotic infection
  • Urinary tract infection
  • Preterm delivery
  • Stillbirth


Early-onset GBS disease can be prevented through intrapartum antibiotic prophylaxis. However, no effective strategy has yet been identified for how to prevent late-onset disease or adult disease.

Keep Reading: Clinical Guidelines

"Prevent Group B Strep" app‎

Obstetric providers: Use this app to achieve better implementation of GBS prevention guidelines.


Neurologic sequelae include sight or hearing loss and cerebral palsy. Death occurs in about 5% of infants and adults.

Drug resistance

There has been widespread use of intrapartum antibiotic prophylaxis to prevent early-onset GBS disease. This antibiotic use has raised concern about the development of antibiotic resistance among GBS isolates.

Learn more about GBS resistance:

Challenges and opportunities

Public health experts are working to

  • Implement universal screening in all prenatal healthcare settings
  • Monitor potential adverse consequences of increased use of antibiotics
  • Identify a strategy for prevention of late-onset disease and adult disease
  • Evaluate candidate GBS vaccines