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Updated: Jun 19, 2026

A Murine Model of Group B Streptococcus Vaginal Colonization
Published on: November 16, 2016
The effect of digital cervical examination on group B streptococcal culture
Eric J Knudtson1, Landon B Lorenz, Valerie J Skaggs
1Department of Obstetrics and Gynecology, the University of Oklahoma Health Sciences Center, Oklahoma City, USA.
Objective:
We sought to evaluate whether group B streptococcus (GBS) detection is altered by the digital cervical examination.
Study Design:
A total of 302 women undergoing the clinical GBS culture had a digital cervical examination and a repeated GBS culture. Statistical comparison of pre-post culture results were performed with kappa and McNemar tests.
Results:
The clinical prevalence of GBS was 19.5%. Discordant results were seen in 30/302 (9.9%) paired cultures (kappa = 0.68; 95% confidence interval, 0.568-0.783). An initially negative GBS culture result was positive on repeated testing in 13/243 (5.3%) pairs. Initially positive cultures were negative on repeated testing in 17/59 (28.8%) pairs. Patients with discordant results had similar characteristics as the remainder of the study group. Given the observed proportion of discordant results (9.9%), the study had 80% power to detect a 5% difference between discordant pairs.
Conclusion:
Paired GBS cultures showed a good level of agreement. The 28.8% rate of positive cultures becoming negative is clinically concerning and warrants further study.
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