Group B Streptococcus early-onset disease in Emilia-romagna: review after introduction of a screening-based approach.

BACKGROUND: Group B Streptococcus (GBS) is a leading cause of neonatal bacterial infections. Early-onset infections have decreased in recent years but, despite considerable efforts poured into prevention, cases continue to occur.OBJECTIVES: To analyze trends and identify determining factors for the persistence of the GBS infections. To evaluate the impact of antenatal screening and intrapartum chemoprophylaxis on the clinical presentation of the infection.METHODS: A prospective cohort, population-based study has been ongoing in Emilia-Romagna (Italy) since 2003. Invasive GBS infections, observed between 2003 and 2008 in infants aged < 7 days were analyzed.RESULTS: Among 214,120 live births, 61 early-infections were observed. Fourteen infants (23.0%) were born preterm. Among 47 infants who were delivered at term, 28 were born to mothers who had no risk factors and 7 were born to mothers who had none other than GBS colonization. Forty-one women at term had been screened prenatally; among them, only 10 were documented as GBS culture-positive.Disease severity was highest in infants at lower gestational ages, but most meningitis cases were observed in term infants born to mothers who were GBS culture-negative at screening.Nine newborns had culture-proven infection despite having received intrapartum antibiotics. They were born to mothers with > or =1 obstetrical risk factors and 5 mothers had been treated during labor with macrolides.CONCLUSION: Most infections presented in infants whose mothers had been screened as GBS culture-negative. Missed opportunities for prevention contributed more than prophylaxis failures to the early-onset disease burden.