TABLE 3.

Progression of infection of fetoplacental units infected by F. nucleatum

Time of infection (h)Ni/NtaFetal statusb (no. of fetuses)Extent of infectionc (no. of fetuses)Localization of F. nucleatumc (no. of fetal units)
AliveDeadFocalDiffuseDBMarginMembranesLabyrinth
0 (uninfected)0/1000000000
242/1411202000
489/1145815510
727/907166555
  • a Ni, number of fetal units infected with F. nucleatum; Nt, total number sampled. Fetal units were sampled from two mice at each time point.

  • b Fetal status of F. nucleatum-infected fetaplacental units was determined by the color of fetuses at the time of dissection. Alive, number of fetuses that remained pink; dead, number of fetuses that had already turned purple.

  • c Determined by immunohistochemical staining of infected fetaplacental units with anti-F. nucleatum antibodies. Shown in each column are the numbers of fetaplacental units with each particular infectious pattern (focal or diffuse) or with infections observed in each particular anatomic area (decidua basalis [DB], margin, membranes, or labyrinth). Focal, isolated symmetric area(s) of bacterial colonization; diffuse, continuous zone of colonization encompassing one third or more of the placental structure affected; DB, maternal decidua basalis; margin, lateral point of intersection between the maternal decidua basalis, maternal decidua capsularis, fetal parietal yolk sac, and placental spongiotrophoblast; membrane, visceral yolk sac and/or amnion; Labyrinth, (zone where vascularized fetal tissue and trophoblast-lined maternal blood spaces interdigitate for gas exchange). Also see Fig. 2a for placental anatomy.