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Clinical Overview

Clinical Features

In neonates two syndromes exist for group B strep (GBS) disease:

  • Early-onset (<7 days old)
  • Late-onset (7-90 days old)

Both can manifest as bacteremia, sepsis, pneumonia, and meningitis. In adults, severe infections can manifest as bacteremia (including sepsis) and soft tissue infections. Pregnancy-related infections include:

  • Bloodstream infections (including sepsis)
  • Amnionitis
  • Urinary tract infection
  • Stillbirth

Etiologic Agent

Streptococcus agalactiae or group B Streptococcus (group B strep, GBS) cause GBS disease.

Incidence

Approximately 30,800 cases of invasive GBS disease occur annually in the United States in all age groups. This number includes invasive disease that manifests most commonly as bloodstream infections. In newborns, approximately 7,600 cases occurred before widespread adoption of prevention guidelines. The rate of early-onset infection decreased from 1.7 cases per 1,000 live births (1993) to 0.22 cases per 1,000 live births (2016). Racial disparities in disease persist with the incidence higher among African Americans for all age groups. Learn more about GBS trends.

Sequelae

Surveillance

Active surveillance for invasive GBS disease is ongoing in a multistate population. Learn more about GBS disease surveillance.

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

Costs

Direct medical costs of neonatal disease before prevention were $294 million annually.

Transmission

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 unknown.

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Risk Groups

Adults with chronic illnesses (e.g., diabetes mellitus, obesity, cardiovascular disease), pregnant women, the fetus, and the newborn are at risk for GBS disease.

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

  • GBS colonization
  • Prolonged rupture of membranes
  • Preterm delivery

Rates are also substantially higher among African Americans and the elderly.

Challenges

Public health experts are working to

  • Implement universal screening in all prenatal health care settings by promoting use of guidelines for prevention of GBS disease
  • Monitor potential adverse consequences of increased use of antibiotics
  • Identify a strategy for prevention of late-onset disease and adult disease

Drug Resistance

The widespread use of intrapartum antibiotic prophylaxis to prevent early-onset GBS disease has raised concern about the development of antibiotic resistance among GBS isolates. Learn more about GBS resistance.

Activities

CDC continues to interface with national organizations, health departments, and community groups to create awareness and promote a universal screening policy in all prenatal care settings. CDC conducts active surveillance through the Active Bacterial Core surveillance (ABCs) in order to monitor rates of GBS disease in 10 states in the country. Researchers and policymakers can use these data for continued research and for evaluating the effect of the prevention guidelines.

References

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