521: Intra-amniotic injection alters the intrauterine microbiome in a primate model of inflammatory preterm birth

Abstract

Identification of causative bacteria in chorioamnionitis has been unyielding, and our prior work examining the intrauterine microbiome in association with histological chorioamnionitis demonstrates the presence of bacteria in the placental membranes that is normally found within oral and vaginal cavities. Here, we aimed to examine changes in the intrauterine microbiome that occur in a primate model of inflammatory preterm birth. Sterile intra-amniotic injections (IA) of saline, lipopolysaccharide (LPS), IL-1B, or Ureaplasma parvum were given to preterm (126-132 days) Rhesus macaques (n=23) with ultrasound guidance. Delivery of offspring occurred via cesarean within one week post-injection. Sterile techniques was utilized in the collection and DNA extraction of oral swabs, stool, placental tissue, vaginal swabs, and meconium. Next-generation sequencing (16S and whole genome shotgun (WGS)) of DNA was performed with negative controls, and resultant sequences were quality filtered prior to analysis. Analysis of 16S sequencing was performed with QIIME, LEfSe, GENE-E, and PICRUSt. Analysis of WGS sequencing was performed using HUMAnN and MG-RAST. Integrative analysis was used to determine the relationships of the microbiome alterations in each cohort with relation to bacterial metabolic pathways. As expected, microbiota of the maternal oral and vaginal cavities was not significantly altered by intra- amniotic injection of LPS, IL-1B, nor U. parvum when examining alpha (Fig. A) and beta diversity. However, intrauterine microbiota were significantly altered by both alpha (p<0.03, Fig. A) and beta (p=0.02, Fig. B) diversity with intra-amniotic injection of inflammatory mediators in comparison to control animals. Furthermore, we found clustering of samples by control or inflammatory injection when examining hierarchal clustering by Spearman’s correlation (Fig. C). This study demonstrates the presence of bacteria in the intrauterine environment due to alterations occurring in placenta microbiota with exposure to inflammatory mediators. Additionally, we find that inflammatory mediators significantly alter the intrauterine microbiome in a clinically relevant primate model.