Clinical Overview

Clinical Features

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

Etiologic Agent

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

Incidence

Approximately 19,800 cases 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 0.28 cases per 1,000 live births (2008). 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 among blacks approximately twice that of non-blacks for all age groups.

Sequelae

Neurologic sequelae include sight or hearing loss and cerebral palsy. Death occurs in 5% of infants and 8% of 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 vagina occurs. Mode of transmission of disease in nonpregnant adults is unknown.

Risk Groups

Adults with chronic illnesses (e.g., diabetes mellitus 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.

Surveillance

Active surveillance for invasive group B strep disease is ongoing in a multistate population of approximately 33 million, including approximately 500,000 live births annually. The disease is not reportable in most states.

Trends

This pathogen emerged in the 1970s as the most common cause of sepsis in newborns. Adult disease was recognized more recently and the incidence has been increasing. Early-onset disease has declined by 80% since increased use of intrapartum prophylaxis has occurred.

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 in 10 states in the country; this data can be used for continued research and to evaluate the effect of the newest guidelines.

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