Age dependence of in vitro survival of meningococci in whole blood during childhood.

OBJECTIVES: To determine the association between the ability of a different strains of meningococci to survive in whole blood and the age of the donor. METHODS: A panel of serogroup B and a serogroup C strain of Neisseria meningitidis was tested in an ex vivo whole blood model. Blood from 81 healthy children and 20 adults and from children during convalescence from serogroup B (55 patients) or serogroup C (43 patients) meningococcal infection was assessed. RESULTS: Age-dependent acquisition of whole blood killing of serogroup B and C bacterial isolates was demonstrated in healthy children with an inverse relationship to the reported incidence of disease. After infection with serogroup B or C meningococci, evidence of whole blood killing of the bacteria was found even in blood from children