Open AccessStreptococcus agalactiae do not penetrate human chorioamniotic membranes in vitro but alter their biomechanical properties
Author(s) -
Mohamed Nasteha A.,
Hinge Mogens,
Larsen Ole H.,
Sørensen Uffe B. S.,
Uldbjerg Niels,
Nejsum Lene N.
Publication year - 2021
Publication title -
acta obstetricia et gynecologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 102
eISSN - 1600-0412
pISSN - 0001-6349
DOI - 10.1111/aogs.14232
Subject(s) - streptococcus agalactiae , chorioamnionitis , rupture of membranes , medicine , membrane , neonatal sepsis , fetal membrane , microbiology and biotechnology , fetus , streptococcus , pregnancy , biology , immunology , sepsis , bacteria , placenta , biochemistry , genetics
Vaginal colonization with Streptococcus agalactiae (group B streptococci) is hypothesized to constitute a risk factor for preterm prelabor rupture of membranes. In vitro studies have shown that S . agalactiae strains isolated from infants with neonatal sepsis adhere to chorion cells of the human chorioamniotic membrane. However, it is still unknown whether S . agalactiae strains penetrate the chorioamniotic membranes and whether S . agalactiae colonization affects the biomechanical properties of the membranes and thus contributes to increased risk of preterm prelabor rupture. The aim of this in vitro study was to explore if different strains of S . agalactiae penetrate and affect the biomechanical properties of human chorioamniotic membranes. Material and methods Three different strains of S . agalactiae were obtained, one from an early‐onset neonatal infection, one from a case of preterm prelabor rupture of membranes and one from a healthy pregnant carrier. Chorioamniotic membranes from elective cesarean deliveries were either incubated with S . agalactiae or mounted in a two‐chamber incubation cell generating a “maternal” and a “fetal” chamber and incubated with S . agalactiae in the maternal chamber. Subsequently the membranes were examined to evaluate S . agalactiae attachment, penetration and the effect on the biomechanical properties. Results At 5 h after incubation, S . agalactiae adhered to the chorioamniotic membranes with increased number at 20 h. Streptococcus agalactiae did not penetrate the membranes even after 20 h of incubation. Streptococcus agalactiae increased the ultimate tensile stress needed to rupture the membranes and increased the work needed to rupture the membranes as well as the elastic modulus. Conclusions Human chorioamniotic membranes constitute a physical barrier against S . agalactiae infections. Moreover, S . agalactiae infection leads to increased strength of the membranes.