Neuropathological findings in 9 cases of listeria monocytogenes brain stem encephalitis.

Brain stem encephalitis is a particular manifestation of infection with the bacterium Listeria monocytogenes. Here, we present the neuropathological findings in 9 such cases. In the brain stem, the inflammatory infiltrates were located predominantly within nuclei and tracts of cranial nerves innervating the oropharynx. These findings support the hypothesis that the food-borne bacterium Listeria monocytogenes invades the brain stem along cranial nerves.