Characterization of Chorioamnionitis in 2nd-Trimester C-Section Placentas and Correlation with Microorganism Recovery from Subamniotic Tissues

Abstract

Prolonged exposure to infection appears to influence fetal/neonatal development. We characterize the relationship between histologic patterns of inflammation and microorganism recovery from the placentas of live born infants delivered before the 28th postmenstrual week. The subamniotic parenchyma of 835 placentas delivered by cesarean section were cultured and evaluated for specific histologic patterns of inflammation in a blinded fashion. Cases with prolonged membrane rupture were excluded. Microorganisms were recovered from 41% of placentas. Microorganisms found more frequently in placentas with high-grade chorionic plate inflammation include Actinomyces, Prevotella bivia, Corynebacterium sp., Escherichia coli, Peptostreptococcus magnus, multiple species of Streptococci, and Mycoplasma sp., including Ureaplasma urealyticum. These microorganisms were also associated with fetal vasculitis (neutrophilic infiltration of chorionic plate stem vessels or umbilical cord). Recovery of microorganisms from placental parenchyma is associated with histologic inflammation. The same microorganisms responsible for inciting high-grade chorionic plate inflammation are also most likely to promote fetal inflammation.

Antecedents of chronic lung disease following three patterns of early respiratory disease in preterm infants

“…The presence of chorioamnionitis and funisitis was determined by an ELGAN study pathologist at each institution who first engaged in training procedures to minimise interobserver variability, was masked to maternal history, and used predefined operational definitions; 1126 placentas were examined 5 6…”

The placenta in preterm birth

“…Clinically, the most common pathogens are the genital mycoplasmas (especially Ureaplasma urealyticum ) and Streptococcus agalactiae , Escherichia coli , Fusobacterium sp., and Gardnerella vaginalis 79. Group B streptococcus, Staphylococcus , Propionibacterium , Peptostreptococcus , Pseudomonas , Proteus and Klebsiella species have also been commonly associated with acute clinical or pathological chorioamnionitis 29 35 52 . Candida albicans , while an uncommon pathogen, has been associated with high rates of morbidity and mortality in early preterm infants 66.…”

“…Many of these have been associated with bacterial vaginosis, a condition in which the normal vaginal flora of lactobacilli are replaced by other low and high grade pathogens. However, the exact rates of infection and factors that determine a given maternal–fetal dyad’s susceptibility to infection and SPTB are unclear 31 35 79. Microbiological studies of amniotic fluid have shown that overall rates of infection in preterm birth are 25–40%; some 32.5% of women with PTL and delivery and over 75% who deliver following PPROM have positive amniotic fluid cultures 31.…”

Correlation between Clinical, Placental Histology and Microbiological Findings in Spontaneous Preterm Births

“…In the current study, inaccuracies were minimized by the use of multiple sources for identifying specific maternal and neonatal parameters, and by manual validation of each individual medical file. Contamination from vaginal flora or normal skin may be unavoidable with the technique used in the current study compared to other techniques in which cultures were taken from the area between the chorion and the amnion [18]. However, among the 91 positive chorioamnionic cultures in the study group, only 2 (2.2%) isolations were lactobacilli and coagulase-negative staphylococci.…”