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Updated: Apr 24, 2026

A Murine Model of Group B Streptococcus Vaginal Colonization
Published on: November 16, 2016
Maternal β-hemolytic streptococcal pharyngeal exposure and colonization in pregnancy
Giv Heidari-Bateni1, Anoop K Brar1, Matthew Hall2
1Division of Pediatric Cardiothoracic Surgery, Washington University School of Medicine, St. Louis, MO 63110, USA.
Objectives:
To report the pharyngeal colonization rate of β-hemolytic streptococci and changes in the value of antistreptolysin O (ASO) and anti-DNase B serology titers during pregnancy.
Methods:
Healthy pregnant women were recruited and blood was drawn in each trimester. The upper limit of normal (ULN) values for ASO and anti-DNase B was calculated for each trimester. Throat swabs were collected for culture and positive cultures were further assessed for the identification of serogroup of the isolated β-hemolytic streptococcus.
Results:
Out of a total of 126 pregnant women, 34.1% had positive throat cultures. Group C and group G strains were isolated in 18.2% of throat cultures while group F was detected in 13.5% of cases. The rate of colonization with GAS was 1.6%. There was an overall drop in ASO titer during pregnancy while anti-DNase B titers remained relatively unchanged. ULN values of 164(IU), 157(IU), and 156(IU) were calculated for ASO at the first, second, and third trimesters, respectively. Based on the ULN values, 28.6% of patients had recent streptococcal exposure.
Conclusions:
These results show that pregnant women act as a reservoir for spreading potentially immunogenic (groups C and G) and disease producing (group F) virulent strains of streptococci.
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