Genomic rearrangements in Neisseria meningitidis strains of the ET-5 complex

A physical map of the chromosome of Neisseria meningitidis strain 44/76, wh ich belongs to the epidemic clone ET-5, was constructed. DNA fragments obta ined after SfiI and NheI digestion were resolved by pulsed field gel electr ophoresis (PFGE). The overall arrangement of 26 genetic markers localized o n the 2.3-Mb chromosome was conserved in comparison with that in meningococ cal strains B1940 and Z2491. Simplified physical maps of 29 additional stra ins belonging to the ET-5 complex isolated from various parts of the world were compared with that of strain 44/76. Ten distinct patterns of hybridiza tion were identified. While two of the seven probes hybridized to fragments of the same size in all strains, the remaining probes hybridized to differ ent fragments, in some cases to fragments not adjacent on the chromosome of 44/76. These results indicated the occurrence of genetic rearrangements in the genome of the ET-5 meningococcal clone in the course of its epidemic s pread.