Group B streptococcal infections in the neonate.

The incidence of disease caused by the Group B streptococci (GBS) has risen significantly in the past two to three decades and the GBS are now a leading cause of meningitis in the neonate. The GBS are sub-classified into five groups (Ia, Ib, Ic, II, and III) with type III being the most common, especially in meningitis. The two syndromes, early (first week) and the late (second to twentieth week) are associated with a 50 percent and 20 percent mortality, respectively. The acute syndrome is usually a result of infection from a maternal source whereas the late syndrome is more often associated with nosocomial or community acquisition of GBS. Antibiotic prophylaxis by treating infants at risk or colonized mothers has not proven efficacious; however, maternal antibodies have been shown to afford protection to neonates. Further evaluation of antibiotic prophylaxis and therapy, clarification of the mechanism of acquired immunity versus susceptibility and further characterization of the antigens of GBS with a possibility of a vaccine as a measure of prophylaxis are currently in progress.