The Impact o Molecular Techniques on the Study of Meningococcal Disease.

Neisseria meningitidis, the meningococcus, is normally a harmless commensal bacterium that colonises the naso/oropharynx of humans. This antigenically variable gram-negative diplococcus has the potential, however, to cause rapidly progressing meningitis and fulminant septicemia, either separately or together (1,2). Once present in the bloodstream, meningococci grow rapidly and their highly toxic lipo-oligosaccharides frequently cause extensive tissue damage and severe toxic shock. The progress of the disease is swift, and death often occurs within hours of the onset of symptoms (3). Even in countries where meningococcal infection is relatively rare, it remains a high priority for public health services because of the high mortality rates of fulminant septicemic disease (which can be up to 40% even when intensive supportive therapy is available), the high proportion of sequelae in patients who have recovered (including brain damage and digit or limb loss), and the age groups most susceptible (young children and, to a lesser extent, teenagers) (4,5).