Inhibition of Gestational Pathogens by Placenta Extracts — 103p — Caylee Weber, Grace Lass, Ethyn Rollinger, Jennifer Gubbels, Paul Egland

The placenta is unique because it is an organ that is composed of tissue from two individuals. The placenta serves many important functions in pregnancy, including its contribution to innate immune protection of the fetus. Maternal (chorion) and fetal (amnion) portions from full-term human placentas were assayed for their contribution to this protection. Using in vitro assays, the antibacterial activity of cell-free placenta extracts was measured against four human pathogens that are most frequently associated with negatively affecting gestational and neonatal health: Streptococcus agalactiae, Fusobacterium nucleatum, Escherichia coli K1 and Listeria monocytogenes. These antimicrobial properties were tested to determine their inhibition of bacterial biofilm formation by quantifying the difference in biofilm growth in 96-well plates. Placental antibacterial properties against suspended cells were assessed using a live/dead assay measured by flow cytometry. Extracts from human placenta samples exhibited antibacterial activity against all bacterial species tested as suspended cells. Biofilm formation by E. coli was inhibited by both pretreatment of surfaces with placenta extract and by growth in the continuous presence of placenta extracts. Continuous placenta exposure also inhibited biofilm growth by L. monocytogenes. In contrast, pretreatment of surfaces with human placenta extracts enhanced biofilm formation by L. monocytogenes. The differences in biofilm formation suggest that L. monocytogenes may bind to certain components of the placenta while being inhibited by others.

University of Sioux Falls
Paul Egland