Neonatal Group B Streptococcal Infections: Overview and Prevention Strategies

Emerging abruptly in the 1970s as an important life-threatening pathogen in neonates causing severe invasive bacterial infections, Streptococcus agalactiae or group B streptococcus (GBS) has become a notable global problem. Today it remains the leading cause of neonatal sepsis and meningitis, early onset and late onset diseases (EOD, LOD). From the 1990s to the present, where guidelines for prevention of perinatal GBS disease have been widely implemented, the incidence of EOD has dramatically decreased to <0.5 cases per 1,000 live births but has not been eradicated. Selective intravenous antimicrobial prophylaxis with β-lactams administered during labor and delivery to women who are colonized by GBS appears to be the most practical and effective mode of prevention of GBS EOD at this time. There are different prevention strategies at this time, screening-based or risk-based, but none are 100% effective in the eradication of neonatal GBS EOD and there are no preventive strategies for LOD. In spite of the great progress that has been made, GBS EOD continues to occur and the GBS burden remains a significant public health issue. Extended efforts to improve screening for GBS status continue to be important and may be able to take advantage of new rapid diagnostic technologies. Given challenges, limitations and potential complications of maternal intrapartum prophylaxis, a new approach is still needed. Maternal immunization against GBS is an attractive alternative for the prevention of not only EOD and LOD but also stillbirths and maternal diseases. Development of a group B streptococcal vaccine is the most promising approach for the prevention of severe GBS neonatal disease through transplacental delivery of antibodies directly from immunized mothers. It may likely become the most effective and sustainable long-term preventive strategy.