Group B Streptococcus (GBS
Streptococcus agalactiae) is a gram-positive colonizer of the healthy intestinal and genitourinary microbiota. During and shortly after birth, neonates and infants can be opportunistically infected leading to sepsis, pneumonia, or meningitis among other illnesses. GBS is the leading cause of neonatal meningitis globally, and while prophylactic treatments have been successful for reducing early-onset disease, no decrease in the incidence of late-onset disease has occurred and no vaccine is currently available. In this review, we describe GBS both from a clinical and molecular standpoint. We first describe the history of GBS perinatal disease and its clinical presentation and treatment, as well as patient outcomes. We then present recently discovered GBS interactions at the blood-brain barrier that contribute to disease and inflammatory responses, and efforts to develop a broadly effective GBS vaccine.