Classification of Neisseria meningitidis Group B into Distinct Serotypes. III. Application of a New Bactericidal-Inhibition Technique to Distribution of Serotypes among Cases and Carriers

Abstract

The development of sensitive serologic techniques in this laboratory has enabled the subdivision of group B meningococci into 11 distinct serotypes. The establishment of serologic types within group B has permitted these preliminary epidemiologic studies of disease due to group B Neisseria meningitidis. A sensitive technique for bactericidal inhibition is described. This technique and two other methods have been used to serotype a large number of group B strains. Strains with the type 2 antigen (i.e., type 2-associated serotypes) were the most prevalent. Almost 75% of the group B, type 2-associated strains examined were isolated from patients with meningococcal disease. In addition, 69% of these type 2-associated strains were resistant to sulfisoxazole at a concentration of 0.1 mg/ 100 mI, whereas only 17% of non-type 2 serotypes were resistant to this level of sulfisoxazole. When strains from carriers were examined, the non-type 2 serotypes represented 78% of these carrier strains.