Maternalβ-Hemolytic Streptococcal Pharyngeal Exposure and Colonization in Pregnancy

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.

Clinical Characteristics of and Preventative Strategies for Peripartum Group A Streptococcal Infections

“…A recent study investigating the incidence of pharyngeal group A streptococci colonization in pregnancy reported a rate of 1.6%; however, it did not examine additional screening sites. 17 Second, although the carrier status of group A streptococcal infection is estimated at 5% among adults 18 and may reach 16% among young children, 19 the reported incidence of group A streptococci colonization in pregnancy is surprisingly low, especially when considering the fact that many pregnant women have schoolaged children. This and more, pregnancy in itself is associated with immune system modulation and susceptibility to upper respiratory tract infections.…”

“…This is based on data that mostly relies on a single screening site, for the most part, throat culture. 17 Thus, it may underestimate the actual rate of streptococci carriers among staff and may miss the index carrier. Further studies should allude to this major concern.…”

Streptococcus G leading to septic abortion and multiple organ failure

“…All isolates were sensitive to penicillin. A recent study shows that pregnancy is associated with a high rate of colonization with streptococcal groups F, C, and G. The incidence of positive throat cultures for βhemolytic streptococci is 40% and the incidence of group G strains is 6.3% [7]. The relatively prevalent β-hemolytic streptococci colonization in pregnancy could explain the sepsis of the present patient; could the amygdalitis experienced few days before lead to hematogenous spread of streptococcus G to the gestational sac?…”