Multilocus restriction typing: a tool for Neisseria meningitidis strain discrimination.

Invasive disease-associated strains of Neisseria meningitidis were analysed by multilocus restriction typing (MLRT), which involves the restriction fragment-length polymorphism analysis of PCR products generated from the seven loci of housekeeping genes used in MLST. Several different restriction patterns (alleles) were observed for each of the seven loci examined. Greater allelic variation was observed with the fumC and pgm loci than with the abcZ and adk loci, suggesting that the latter were more conserved. The alleles at each of the seven loci were combined to give an allelic profile or restriction type (RT). A good correlation between RT and serogroup, serotype and serosubtype was observed, as all C 2ap1.2,5 strains were contained in a single RT, as were all but one strain of B 4p1.4. In this study, MLRT proved to be an efficient, effective and relatively inexpensive method for N. meningitidis strain characterization.