Virulence Factors of Invasive Group B Streptococcus Isolates Obtained from Pregnant Women and Neonates

Streptococcus agalactiae, or group B streptococcus (GBS), is an important pathogen for pregnant women and neonates, which can cause preterm birth, stillbirth, maternal sepsis and neonatal invasive disease. GBS are highly heterogeneous in their virulence factor expression and thus can exist as commensal bacteria or become highly invasive. In the U.S., universal screening for GBS is performed at 37-38 weeks gestation and women testing positive are treated with intrapartum antibiotic prophylaxis to prevent neonatal invasive disease. However, these measures do not prevent all GBS disease. If identification of specific GBS virulence factors correlates with invasive disease, their inhibition can prevent GBS perinatal disease and potentially reduce the use of antepartum antibiotics. The study objective was to determine if key virulence factors [e.g., hemolytic pigment (beta-hemolysin), CAMP factor, hyaluronidase] correlate with maternal and neonatal GBS invasive disease.