Characterization of serogroup A Neisseria meningitidis strains by rRNA gene restriction patterns and PCR: correlation with the results of serotyping, subtyping and multilocus enzyme electrophoresis.

We studied 35 strains of Neisseria meningitidis serogroup A from different locations (France, Central African Republic, Sudan and Burkina Faso) using both ribotyping and a polymerase chain reaction (PCR). A non-radioactive probe label was used for ribotyping; detection consisted of an immunoenzymatic procedure using a bispecific antibody. The PCR was designed to amplify the 16S-23S rDNA internal transcribed spacer. These techniques were compared with other markers. The strains were identified as belonging to three clones (I, III-1, IV) by multilocus enzyme electrophoresis (MEE) and to three subtypes by serological methods. Ribotyping identified five groups and PCR identified four groups. Ribotyping gave more diversity between strains than either MEE or sero/subtyping, but confirmed the epidemiological data provided by the combination of these two techniques. The PCR provided a simple and convenient one-step procedure for the differentiation of strains of serogroup A.