Clinical Overview

Clinical Features

In neonates two syndromes exist: early-onset (<7 days old) and late-onset (7-90 days old). Both can manifest as sepsis, pneumonia, and meningitis. In adults, severe infections can manifest as bloodstream (including sepsis) and soft tissue infections. Pregnancy-related infections include bloodstream infections (including sepsis), amnionitis, urinary tract infection, and stillbirth.

Etiologic Agent

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

Incidence

Approximately 26,500 cases of severe group B strep infections, including invasive disease that manifests most commonly as bloodstream infections, occur annually in the United States in all age groups; approximately 7,600 cases occurred in newborns before recent prevention. The rate of early-onset infection has decreased from 1.7 cases per 1,000 live births (1993) to 0.24 cases per 1,000 live births (2014). Since active prevention began in the mid-1990s, the rate of group B strep disease among newborns in the first week of life has declined by 80%. Racial disparities in disease persist with the incidence higher among blacks for all age groups.

Sequelae

Neurologic sequelae include sight or hearing loss and cerebral palsy. Death occurs in 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, and cardiovascular disease), pregnant women, the fetus, and the newborn are at risk. For neonatal disease, risk is higher among infants born to women with group B strep colonization, prolonged rupture of membranes, or preterm delivery. Rates are substantially higher among blacks and the elderly.

Challenges

To implement universal screening in all prenatal health care settings by promoting use of CDC guidelines for prevention of group B strep. To monitor potential adverse consequences of increased use of antibiotics. To identify a strategy for prevention of late-onset disease and adult disease.

Activities

Interface with national organizations, health departments, and community groups to create awareness and promote a universal screening policy in all prenatal care settings. Continued active surveillance by the Active Bacterial Core surveillance (ABCs) — to monitor rates of group B strep disease in 10 states in the country; these data can be used for continued research and to evaluate the effect of the newest guidelines.

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