Related Experiment Video
Updated: Apr 13, 2026
A Murine Model of Group B Streptococcus Vaginal Colonization
Published on: November 16, 2016
Comparison of pre- and intrapartum screening of group B streptococci and adherence to screening guidelines: a cohort
Mirjam Kunze1, Katharina Zumstein, Filiz Markfeld-Erol
1Department of Gynecology and Obstetrics, University Medical Center Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany, mirjam.kunze@uniklinik-freiburg.de.
Insights
Prepartum screening for group B Streptococcus (GBS) is effective in predicting intrapartum colonization, though improved adoption strategies are necessary. This study evaluated GBS screening methods in pregnant women, finding similar colonization rates between prepartum and intrapartum screenings.
Area of Science:
- Obstetrics and Gynecology
- Infectious Diseases
- Microbiology
Background:
- Group B Streptococcus (GBS) prepartum screening (PS) evaluation is limited.
- Predictive value of PS for intrapartum colonization requires further study.
- Longitudinal GBS screening data is crucial for program evaluation and vaccine development.
Purpose of the Study:
- To assess prepartum GBS screening (PS) at 35-37 weeks gestation.
- To compare the predictive value of PS versus intrapartum screening (IS).
- To evaluate intrapartum antibiotic prophylaxis (IAP) rates and GBS transmission to neonates.
Main Methods:
- A surveillance cohort study of 937 pregnant women at a tertiary care center.
- Comparison of GBS colonization status from PS and IS.
- Calculation of positive predictive value and IAP rates.
- Neonatal GBS transmission assessment via cultures.
Main Results:
- 67.5% of women had PS, with only 22.7% adhering to guidelines.
- Maternal GBS colonization rates were similar: PS (18.5%) vs. IS (17.0%).
- Positive predictive value of PS for intrapartum GBS positivity was 77.2%.
- 89.3% of women with positive PS received IAP.
- GBS serotype distribution remained stable compared to a 2003-2004 study.
Conclusions:
- Improved strategies for prepartum GBS screening adoption are needed.
- Prepartum GBS screening accurately predicts intrapartum colonization.
- Stable serotype distribution suggests potential long-term efficacy of GBS vaccines.
Unlabelled:
Implementation of guidelines for group B streptococcal (GBS) prepartum screening (PS) rarely has been prospectively evaluated. To assess PS at 35-37 weeks of gestation and compare its predictive value to that of an intrapartum screening (IS) within 7 days of delivery, a surveillance cohort study was conducted at a tertiary care center in Freiburg, Germany, during 2011-2012. Study participants included 937 pregnant women who had intrapartum cultures taken for vaginal and rectal GBS colonization. Colonization status was compared to PS, and intrapartum antibiotic prophylaxis (IAP) rates calculated. The neonates were tested for GBS transmission via cultures from their throats and external ear canals. While 67.5% (633/937) of study participants had a PS, only 22.7% (144/633) underwent a fully guideline-compatible PS. However, maternal GBS colonization rates were similar when comparing PS (18.5% [117/633]) versus IS (17.0% [133/784]). The positive predictive value of a positive PS result for GBS positivity at delivery was 77.2 %. Women with a positive PS received IAP in 89.3% of cases (75/84). The capsular serotype distribution pattern of colonizing GBS strains has not changed in comparison to our 2003-2004 study--one with a similar study design.
Conclusions:
Improved strategies for adoption of prepartum GBS screening are needed.
What Is Known:
• The prediction of prepartum GBS screening for intrapartum colonization status has not been well studied. • Longitudinal studies of GBS screening are needed for screening program evaluations and vaccine development. What is New: • The rate of GBS screening has improved over 10 years, and intrapartum GBS colonization prediction was accurate. • Serotype distribution was stable and suggests the potential long-term efficacy of GBS vaccines.
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