Multilocus genotypes of two strains of Neisseria meningitidis and their presumed variants obtained upon subcultivation.

ABSTRACT

Loss of sulfonamide resistance and endotoxin liberation have been described in two strains of Neisseria meningitidis serogroup B, upon subcultivation every 1 to 2 months over an 18-month period. Subsequently, the two laboratory variants, designated 270E- and 840E-, were also found to differ from the parent strains, 270E+ and 840E+, in serotype, outer membrane protein pattern, and virulence in mice. We report here the multilocus genotypes determined by enzyme electrophoresis, of the four isolates 270E+, 270E-, 840E+, and 840E-, and demonstrate that 270E- and 840E- strains could not have originated from subcultivation of 270E+ and 840E+, respectively, but that a mix-up of strains has occurred.