Blood and brain bacterial counts after intraperitoneal challenge.

Congenic mice (wild-type, human transferrin expressing transgenic mice with or without IAV infection) were challenged by intraperitoneal injection of 5*10⁶ CFU of the N. meningitidis serogroup C strain LNP24198. At each indicated time point, mice were anaesthetized, blood samples were withdrawn and then perfusion was performed for each mouse to wash out blood using phosphate saline buffer. Brains were then extracted. Blood and brain samples were plated to determine the bacterial counts in each fraction. Data represent the means ± SD from 5 independent experiments of groups of five mice per time point in each experiment.