Endotoxin liberation by strains of N. meningitidis isolated from patients and healthy carriers.

The main objective of this study was to assess whether the capacity of Neisseria meningitidis to release endotoxin depends upon the type of strain or upon bacterial mass. Endotoxin release was studied in 32 strains isolated from patients with meningococcal infections and in 49 from asymptomatic carriers, using a quantitative test (limulus test with a chromogenic substrate). The results show that the strains from patients release significantly higher amounts of endotoxin than strains from carriers regardless of serogroup and isolation site. No correlation was found between stage of bacterial growth and the amount of endotoxin liberated. These findings suggest that endotoxin liberation is a characteristic of certain strains of N. meningitidis and is not determined simply by bacterial mass.