Selective maternal culturing to identify group B streptococal infection.

During a 5-year period vaginal cultures were obtained from all women with an obstetric history of premature onset of labor or premature rupture of membranes. With these indications, 1,213 (12.7%) of all parturient patients were cultured and 10.2% of those cultured were colonized with group B beta-hemolytic streptococci. Maternal colonization did not correlate with ABO blood group, although a significantly higher percentage of Rh negative women were colonized (p < 0.01). During this 5-year period, 20 infants had documented early-onset infection (sepsis or meningitis) with group B beta-hemolytic streptococci. All 10 infants had a maternal history of premature onset of labor and/or premature rupture of membranes. Mothers of eight infants were cultured and seven of these cultures were positive. Approximately one of every 20 infants designated at high risk actually developed early-onset disease. Selective maternal culturing effectively identifies those infants as risk for early-onset group B streptococcal disease.