Group B Streptococcal infection in neonates and colonization in pregnant women: An epidemiological retrospective analysis

Background: Group B Streptococcus (GBS) infection is one of the major causes of neonatal morbidity and mortality. Universal GBS screening with intrapartum antibiotic prophylaxis (IAP) in pregnant women were initiated in 2012 in Taiwan. This study aimed to analyze the most recent maternal GBS colonization rate and the changes in neonatal GBS infection rate from 2011 to 2016. Methods: All pregnant women and their live born neonates between January 2011 and June 2016 were retrospectively reviewed. Whether GBS screening was done, screening results, presence of risk factors, the use of antibiotics, and neonatal outcome were analyzed. In addition, hospitalized neonates diagnosed with GBS infections were retrieved for comparison of early onset disease (EOD) (<7 days) and late onset disease (LOD) (>= 7 days). Results: A total of 9535 women delivered babies during the study period. The maternal GBS screening rate was 71.0% and the colonization rate was 22.6%. The overall neonatal invasive GBS infection rate was 0.81 per 1000 live births and the vertical transmission rate was 1.2%. After 2012, the invasive neonatal GBS infection rate declined from 1.1-1.6 parts per thousand to 0.6-0.7 parts per thousand in 2014 and thereafter, the GBS EOD incidence rate declined from 2.8 parts per thousand to 0.0-0.6 parts per thousand, but the LOD incidence rate remained approximately 0.7 parts per thousand. Infants with EOD had strong association with obstetric risk factors. Conclusions: Taiwan's universal GBS screening with IAP program reduced the incidence rate of neonatal GBS EOD to be lower than 1 parts per thousand after 2012. Pediatricians still should pay attention to infants with GBS LOD since its incidence rate remained unchanged. Copyright (C) 2017, Taiwan Society of Microbiology. Published by Elsevier Taiwan LLC.