CHARACTERIZATION OF SEROGROUP-A NEISSERIA-MENINGITIDIS STRAINS BY RIBOSOMAL-RNA 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 diffe rent locations (France, Central African Republic, Sudan and Burkina Fa so) using both ribotyping and a polymerase chain reaction (PCR). A non -radioactive probe label was used for riboryping; detection consisted of an immunoenzymatic procedure using a bispecific antibody. The PCR w as designed to amplify the 16S-23S rDNA internal transcribed spacer. T hese techniques were compared with other markers. The strains were ide ntified as belonging to three clones (I, III-1, IV) by multilocus enzy me electrophoresis (MEE) and to three subtypes by serological methods. Ribotyping identified five groups and PCR identified four groups. Rib otyping gave more diversity between strains than either MEE or sero/su btyping, but confirmed the epidemiological data provided by the combin ation of these two techniques. The PCR provided a simple and convenien t one-step procedure for the differentiation of strains of serogroup A .