I do not know a lot about bacterial meningitis, but I don't believe that it actually passes through the barrier. Meningitis is caused by the inflammation of a membrane that the brain and spinal chord are encased within [1]. So it might be causing the membrane to become enflamed from the outward facing surface.
There has been some potentially revolutionary work at CalTech with respect to the link between intestinal bacterial and Parkinson's (see link below). If it pans out it could potentially open up entirely new avenues of treatment.
