Assessment of maternal GBS colonization and early-onset neonatal disease rate for term deliveries: a decade perspective

: Objective To assess the maternal group B streptococcal (GBS) colonization rate and neonatal early-onset GBS (EOGBS) disease in term deliveries, a decade apart. Methods This was a retrospective computerized study between 2005 and 2016. A universal GBS culture-based approach gradually replaced the GBS risk-oriented screening. A vaginal-rectal culture taken at 35-37 weeks was recorded at admission for delivery. Results We identified 149,910 term deliveries during the study period. GBS status was recorded in 53,879 (35.9%) cases. The GBS screening rate constantly increased from 20% in 2005 to 47.5% in 2016. GBS colonization rates significantly decreased, from 50.3% in 2005 to 31.7% in 2016, P<0.001. Overall, EOGBS disease was diagnosed in 37 term neonates (0.25 per 1000 live births.). The rate of EOGBS in neonates decreased dramatically from 0.361 per 1000 deliveries between 2005 and 2009 to 0.19 per 1000 deliveries between 2010 and 2016 (P<0.05). During the latter period, over 35% of the deliveries were screened for GBS. Remarkably, 64.9% of the EOGBS originated in the non-screened population. Conclusion The universal screening policy was associated with a significant decrease in neonatal EOGBS and therefore should be adopted. Further national surveillance studies should be performed in order to validate this approach.