FIG. 7.

Histopathology of rat brain tissue 18 h after inoculation of ExPEC wild-type strain 408 (A), ExPEC 408 cured of pAPEC-O103-ColBM (B), and ExPEC 408 complemented with pAPEC-O103-ColBM (C). In panels A and C, moderate diffuse meningitis was observed (arrows), with neutrophils and lymphocytes scattered throughout the cerebral parenchyma and mild areas of edema. There were similar inflammatory cells that were scattered throughout the cerebral parenchyma and mild areas of edema (not shown). The plasmid-cured strain (B) (the lower magnification shows a larger region) did not cause any lesions.