Neisseria meningitidis. Coloured Transmission electron micrograph of the bacteria Neisseria meningitidis, the agent which causes meningitis. These are non-motile, Gram-negative coccus (spherical) bacteria. At lower frame a cell has undergone a double cell division, producing 4 bacterial cells. Neisseria meningitidis is an obligate human parasite. It causes meningococcal (cerebrospinal) meningitis, the inflammation of connective tissue membranes lining the brain & spinal cord. Symptoms include headache, fever, muscle rigidity, delirium, sometimes death. Treatment with antibiotics. Magnification: x42,500 at 6x7cm size. Magnification: x125,000 at 10x8 inch size.