Maternal β-hemolytic streptococcal pharyngeal exposure and colonization in pregnancy.

Giv Heidari-Bateni,Anoop K Brar,Madeleine W Cunningham,Trupti Hathcock,Matthew Hall,Deirdre Epstein,Pirooz Eghtesady,Lisa S Goessling

doi:10.1155/2014/639141

Abstract

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 164IU, 157IU, and 156IU 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.

Highlights

Pregnancy is associated with physiological changes in the respiratory system [1]
Our group has previously suggested that maternal exposure to rheumatogenic groups of β-hemolytic streptococcus may play a role in pathogenesis of congenital heart disease in the unborn fetus [6], potentially mediated by streptococcal-induced anti-cardiac myosin antibodies [7]
We report for the first time that pregnancy is associated with a high rate of colonization with streptococcal group F and streptococcal groups C and G and this colonization is more prevalent among smokers

Summary

Introduction

Prior studies have suggested that pregnant women, as a result of modulations in the immune system, are more susceptible to upper respiratory tract infections [1, 2]. Our group has previously suggested that maternal exposure to rheumatogenic groups of β-hemolytic streptococcus may play a role in pathogenesis of congenital heart disease in the unborn fetus [6], potentially mediated by streptococcal-induced anti-cardiac myosin antibodies [7]. The point prevalence of β-hemolytic streptococcal pharyngeal colonization in the last trimester of pregnancy has been recently reported to be 8% in a small group of pregnant women in United Kingdom [8]. The pregnancy incidence rate, has not yet been studied and is anticipated to be much more than the reported point prevalence. The two-year incidence rate has been reported to be 19.4% [9]

Objectives

Results

Discussion

Conclusion