The National Neisseria Network (NNN) has undertaken meningococcal isolate surveillance by means of a collaborative laboratory based initiative since 1994. The phenotype (serogroup, serotype and serosubtype) and antibiotic susceptibility of 343 isolates of Neisseria meningitidis from invasive cases of meningococcal disease were determined in 1997. Ninety six percent of the invasive isolates were...

Population and evolutionary analyses of pathogenic bacteria are frequently hindered by sampling strategies that concentrate on isolates from patients with invasive disease. This is especially so for the gram-negative diplococcus Neisseria meningitidis, a cause of septicemia and meningitis worldwide. Meningococcal isolate collections almost exclusively comprise organisms originating from patient...

The National Neisseria Network has undertaken meningococcal isolate surveillance by means of a collaborative laboratory based initiative since 1994. The phenotype (serogroup, serotype and serosubtype) and antibiotic susceptibility of 368 isolates of Neisseria meningitidis from invasive cases of meningococcal disease were determined in 1999. Ninety percent of the invasive isolates were either se...

Interrupting the transmission of infectious agents by introducing new vaccines into a population and creating herd immunity has proven to be a remarkable hidden genie for vaccine effectiveness. For example, oneto two-thirds of the effectiveness of the bacterial conjugate vaccines is linked to protection of the unvaccinated. However, the mechanisms of herd immunity are often not well understood,...