Fig. 5: CadD plays a critical role in ascending GBS infection of a pregnant mouse.

A Conceptual diagram of methods utilized in these studies. Pregnant mice were infected with GBS on embryonic day 13.5 and sacrificed 2 days post-infection. Reproductive tissues were collected for analyses. B Bacterial burden within reproductive tissues was evaluated by quantitative culture to determine Log CFU/mg (vaginal tissue was collected from 5 dams per experimental group, uterus tissues were collected from 6 separate dams, and all other tissues were collected from 6 separate fetal-placental units per experimental group). Significant changes in burden were observed between the WT GB112 and ∆cadD mutant in the decidua (*P = 0.0257), placenta (*P = 0.0003), amnion (*P = 0.0312), and fetus (*P = 0.0266) by one-tailed Mann–Whitney U analysis. These results were reversed by genetic complementation in trans resulting in significant changes in burden observed between the ∆cadD mutant and the complemented mutant in the decidua (*P = 0.0185), placenta (*P = 0.0285), amnion (*P = 0.0009), and fetus (*P = 0.0006) by one-tailed Mann–Whitney U analysis. C Histopathological examination of the hematoxylin and eosin-stained placental units at ×100 magnification (inset panel at ×400 magnification). D Placental units were analyzed by immunohistochemical techniques using a polyclonal antibody to stain specifically for GBS (indicated by the brown stain). Microscopic imaging of reproductive tissues from pregnant mice infected with WT GBS (GB112), isogenic ΔcadD mutant (ΔcadD), and the complemented isogenic ΔcadD mutant (ΔcadD:C). Micrographs are representative of analyses performed in a blinded fashion on tissues derived from 6 separate dams per experimental group. Magnification bars indicate 250 μm. All statistical analyses performed were one-tailed analyses.