Meningococcal pathogenesis: at the boundary between the pre- and post-genomic eras.

Meningococcal disease remains an important public health burden worldwide and, indeed, cause of death, particularly in poorer countries. The rapidly progressive nature of infections means that antibiotic therapy often comes too late. Vaccines are of limited efficacy in infants, one of the most vulnerable age groups, and do not exist for bacteria of serogroup B. Hence, much remains to be achieved in terms of vaccine design and the understanding of the pathogenesis of meningococcal disease. The causative bacterium, Neisseria meningitidis, is usually a commensal of the nasopharynx. Factors that lead to the invasion of the bloodstream, often followed by the crossing of the blood-brain barrier and meningitis, may be partly host- and partly bacterium-dependent, but are ill-understood. It is hoped that, taken together with the fundamental knowledge gained from biochemical and genetic studies, the huge amount of new information made available with the recent publication of the genome sequences will help to unlock more of the secrets of the lifestyle and pathogenic potential of this still poorly understood pathogen.