ABSTRACT
Group B Streptococcus (GBS) has been a leading cause of serious bacterial infection in neonates and young infants for more than a quarter of a century. Increased awareness of this important disease resulted in prompt initiation of empiric antimicrobial therapy for suspected cases of neonatal infection based on delineated risk factors, and has been associated with a very significant reduction of mortality and an improved the prognosis for infants with invasive GBS disease. During the 1990s, the overall case fatality rate was about 5%, but in prematurely born infants this is nearly 25%. Contemporary appraisal of the epidemiology of neonatal disease has affirmed that low birth weight and black ethnicity continue to be associated with enhanced risk for early-onset (age <7 days) neonatal disease and also has identified enhanced risk among infants born to Hispanic women [1]. The predominant serotypes of GBS currently causing neonatal and young infant disease are types Ia, III, and the new serotype which appeared in the 1990s, type V. Taken together, these three account for ~80% to 85% of invasive infections identified in a racially and ethnically diverse cohort from metropolitan areas in the United States [1].
