Group B streptococcus and pregnancy : towards an optimal prevention strategy for neonatal Group B Streptococcal Disease

Group B Streptococcus (GBS, Streptococcus agalactiae) has been recognized as an important cause of perinatal morbidity and mortality. The frequency of GBS colonization ranges from 10% to 35% in women of reproductive age. GBS colonization can be transient, intermittent or persistent. Vertical transmission of GBS from mother to child occurs during labor. Studies on vertical GBS transmission in colonized mothers during labor report incidences of colonization of the infant between 16 and 69%. Early-onset group B streptococcal disease (GBS-EOD) occurs in approximately 1% of newborns who are colonized with GBS. Established risk factors for acquiring GBS-EOD are prolonged rupture of membranes, preterm labor, intrapartum fever, GBS bacteriuria during pregnancy or a previous child with GBS-EOD. Intrapartum antibiotic prophylaxis (IAP) given to women at risk of transmitting GBS to their baby may prevent GBS-EOD. Identification of mothers at risk may be performed by screening (taking a culture during pregnancy to detect maternal colonization) and/ or by identifying pregnancies with one or more of the established risk factors for GBS-EOD. Since the overall effect of the Dutch guideline on the incidence of GBS-EOD is disappointing, adaptation of the Dutch guidelines should be reconsidered. The aim of this thesis is to contribute to the information needed for the establishment of an optimal prevention strategy for GBS-EOD. In this thesis, studies on prevalence of GBS carriage, risk factors for GBS-sepsis in relation to GBS carriage, timing of GBS cultures, association of GBS carriage and preterm labor and resistance of GBS for antibiotics are combined.Astellas Pharma BV, BMA BV (Mosos), Memidis Pharma BV, Raad van Bestuur Medisch Centrum Haaglanden, Stichting Ouders van Groep B Streptokokken PatiëntenUBL - phd migration 201

Group B streptococcus and pregnancy : towards an optimal prevention strategy for neonatal Group B Streptococcal Disease

Group B Streptococcus (GBS, Streptococcus agalactiae) has been recognized as an important cause of perinatal morbidity and mortality. The frequency of GBS colonization ranges from 10% to 35% in women of reproductive age. GBS colonization can be transient, intermittent or persistent. Vertical transmission of GBS from mother to child occurs during labor. Studies on vertical GBS transmission in colonized mothers during labor report incidences of colonization of the infant between 16 and 69%. Early-onset group B streptococcal disease (GBS-EOD) occurs in approximately 1% of newborns who are colonized with GBS. Established risk factors for acquiring GBS-EOD are prolonged rupture of membranes, preterm labor, intrapartum fever, GBS bacteriuria during pregnancy or a previous child with GBS-EOD. Intrapartum antibiotic prophylaxis (IAP) given to women at risk of transmitting GBS to their baby may prevent GBS-EOD. Identification of mothers at risk may be performed by screening (taking a culture during pregnancy to detect maternal colonization) and/ or by identifying pregnancies with one or more of the established risk factors for GBS-EOD. Since the overall effect of the Dutch guideline on the incidence of GBS-EOD is disappointing, adaptation of the Dutch guidelines should be reconsidered. The aim of this thesis is to contribute to the information needed for the establishment of an optimal prevention strategy for GBS-EOD. In this thesis, studies on prevalence of GBS carriage, risk factors for GBS-sepsis in relation to GBS carriage, timing of GBS cultures, association of GBS carriage and preterm labor and resistance of GBS for antibiotics are combined

Timing of Group B Streptococcus Screening in Pregnancy: A Systematic Review

Background: Group B streptococcus (GBS) is an important cause of neonatal sepsis. Guidelines advise to collect cultures at 35-37 weeks' gestation and to administer intrapartum antibiotic prophylaxis in case of GBS-positive cultures, as well as in all preterm deliveries. Improved effectiveness of antenatal cultures might help to further decrease GBS early-onset disease. Objective: To determine the best timing of antenatal cultures, which may help establish optimal prevention of perinatal GBS infection in both term and preterm neonates. Methods: PubMed and EMBASE databases were searched for relevant articles published from 1966 to February 2009. Nine articles were included. Information about study features and predictive values of antenatal cultures were abstracted. Results: Positive predictive values for antenatal GBS cultures ranged from 43 to 100% (mean 69%) and negative predictive values from 80 to 100% (mean 94%). GBS cultures collected in late pregnancy had high positive predictive values for colonization during delivery. The negative predictive value was high and relatively constant regardless of GA. Conclusions: This systematic review confirms recommendations to screen pregnant women for colonization of GBS at 35-37 weeks' gestation, but one should be aware of the limitations of screening, with 6% of GBS carriers remaining undetected in antenatal cultures. Copyright (C) 2009 S. Karger AG, BaselClinical epidemiolog