Neonatal group B streptococcal infections.

Group B streptococci remain a leading cause of life-threatening neonatal infection worldwide. The current estimate of incidence in the United States is 1.8 cases per 1000 live births, with a case-fatality ratio of 10% to 20%. Advances in understanding of the pathogenesis of septic shock and meningitis are yielding new approaches to the treatment of these serious infections. Selective intrapartum chemoprophylaxis with ampicillin has been shown to be both effective and cost effective and is gaining more widespread acceptance as a preventive measure. Conjugate vaccines consisting of type-specific group B streptococci capsular polysaccharides coupled to tetanus toxoid or protein membrane antigens of group B streptococci have been shown to prevent neonatal infection in a mouse model of maternal immunization. Such vaccines are now in trials of safety and immunogenicity in humans.