The agent is Neisseria meningitidis that is gram negative diplococci, aerobic, fastidious and produces cytochrome oxidase. Transmission is by direct contact or by respiratory droplets. There are nine serotypes based on their polysaccharide capsules. Types A, B, C, W-135 and Y have clinical importance. Bacterial meningitis can be caused by other organisms.
Virulence factors are attachment pili, capsules and siderophore.
This disease requires immediate, accurate diagnosis and therapy. Treatment - Penicillin, chloramphenicol and cephalosporin. There is a vaccine containing A,C,Y and W-135 polysaccharides. Group B polysaccharide is not very immunogenic.