TITLE:
Protocol for a Diagnostic Accuracy Study of Polymerase Chain Reaction for Detecting Group B Streptococcus Colonisation in Early Labour or with Spontaneous Ruptured Membranes
AUTHORS:
Laura Cunningham, Bradley de Vries, Jon A. Hyett, Hala Phipps
KEYWORDS:
GBS Screening, Group B Streptococcus, Antibiotic Prophylaxis, Early-Onset Group B Strep, Intrapartum, Rapid Diagnostic Test, Protocol, Neonates
JOURNAL NAME:
Open Journal of Obstetrics and Gynecology,
Vol.8 No.11,
September
20,
2018
ABSTRACT: Background: Group B Streptococcus [GBS] is a bacterium which transiently colonises the genital tract and can be
transmitted from mother to baby at birth. Babies colonised with GBS can develop
early-onset group B streptococcus disease [EOGBSD] which can lead to extended hospital stay, disability and
death. One of the primary methods for determining which women are most likely
to be GBS positive at the time of birth is antenatal universal culture-based
screening. Recently Polymerase Chain Reaction [PCR] screening has emerged as a
point-of-care method for screening women during the intrapartum period. This
study will compare the diagnostic accuracy of this new technology and antenatal
culture-based screening at 35 to 37 weeks gestational age, with the reference
standard of formal culture-based testing in labour. Methods: This prospective observational study will take place
in an Australian hospital. Consecutive women with one or more live fetuses, intending
to have a vaginal birth will be asked to participate. Planned screening for GBS
colonisation using microbiological culture on a self-collected specimen will
occur at 35 to 37 completed weeks gestational age as per our usual hospital
policy. A PCR GBS test by Xpert GBS (Cepheid) will be performed on admission to
labour ward or at the time of rupture of membranes. The reference standard will
be a formal GBS culture on a combined lower vaginal and perianal swab. The
sensitivity, specificity, positive and negative predictive values, and positive
and negative likelihood ratios will be estimated for both antenatal screening
and the intrapartum Xpert GBS (Cepheid) point-of-care test and compared to the reference standard. Results: It is expected that the study will be completed by
mid to late 2020. Conclusion: This study has the potential to improve the accuracy of GBS screening of pregnant women and
therefore health outcomes for mothers and babies. There is also the potential
for a cost savings to the health system.