Extracellular virulence factors of group B Streptococci.

Group B Streptococcus (GBS) is the leading cause of severe bacterial infections in human newborn infants. Advances in streptococcal molecular genetics and refinement of in vitro and in vivo model systems of GBS disease have led to the discovery and characterization of several extracellular virulence factors elaborated by this pathogen. This review summarizes our current understanding of GBS extracellular virulence factors including the beta-hemolysin/cytolysin, C5a-peptidase, hyaluronate lyase, CAMP factor, oligopeptidase, and carbohydrate exotoxin CM101. The molecular basis and potential pathogenic role(s) of each factor are considered in the context of neonatal infection.