Epidemiology of group B streptococcal disease in the United States: shifting paradigms

Abstract

Since its emergence 25 years ago, group B streptococcus has become recognized as a cause of serious illness in newborns, pregnant women, and adults with chronic medical conditions. Heavy colonization of the genital tract with group B streptococcus also increases the risk that a woman will deliver a preterm low-birthweight infant. Early-onset infections (occurring at < 7 days of age) are associated with much lower fatality than when they were first described, and their incidence is finally decreasing as the use of preventive antibiotics during childbirth increases among women at risk. New serotypes of group B streptococcus have emerged as important pathogens in adults and newborns. Clinical and laboratory practices--in obstetrics, pediatrics, and clinical microbiology--have an impact on disease and/or its prevention, and protocols established at the institutional level appear to be critical tools for the reduction of perinatal disease due to group B streptococcus. Since intrapartum antibiotics will prevent at best only a portion of the full burden of group B streptococcal disease, critical developments in vaccine evaluation, including study of polysaccharide-protein conjugate vaccines, offer the potential for enhanced prevention in the relatively near future.

FIG. 1

Age distribution of invasive GBS disease in infants, by age in months, weeks, or (for early-onset cases only) days. The data are based on active surveillance in four geographic areas of the United States in 1993 and were obtained from the CDC.

FIG. 2

Incidence (cases per 1,000 births) of invasive early-onset GBS disease by year and area. The data are based on active surveillance in four geographic areas of the United States in 1993 to 1995. Reprinted from reference .

FIG. 3

Screening-based approach to prevention of perinatal GBS disease. Reprinted from reference .

FIG. 4

Risk-based approach to prevention of perinatal GBS disease. Reprinted from reference .

FIG. 5

Age-specific incidence of invasive GBS disease. Data are based on active surveillance in four geographic areas of the United States in 1993 and were obtained from the CDC.