CHARACTERIZATION OF NEISSERIA-MENINGITIDIS ISOLATES BY RIBOSOMAL-RNA GENE RESTRICTION PATTERNS AND RESTRICTION ENDONUCLEASE DIGESTION OF CHROMOSOMAL DNA

The use of ribosomal RNA (rRNA) gene restriction patterns to study the molecular epidemiology of Neisseria was investigated. Ninety-four isolates of Neisseria meningitidis were characterized by their rRNA gene restriction patterns with 16 + 23 S rRNA from Escherichia coli as a probe. Thirteen rRNA gene restriction patterns were recognized; each of these patterns represented between 1 and 30 isolates. Isolates with the outbreak-associated phenotype B15P1.16 (sulphonamide resistant) all gave a single rRNA gene restriction pattern but this pattern also contained isolates with other phenotypes. Further discrimination between isolates was achieved by comparison of banding patterns resulting from restriction endonuclease digestion of chromosomal DNA with Bgl II. This gave a banding pattern consisting of about ten bands which was simple to interpret. Using this technique 94 isolates were classified in 54 patterns containing between 1 and 14 isolates. Restriction endonuclease analysis with Bgl II characterized outbreak-associated isolates with the phenotype B15P1.16 and enabled strains not typable by conventional methods to be identified as probable outbreak-associated isolates. The techniques should prove useful for epidemiological studies.