Abstract
The distribution of the meningococcal insertion sequence IS1301 was analysed in 496 strains of different serogroups and clonal lineages of Neisseria meningitidis, and in 64 neisserial strains other than N. meningitidis. IS1301 was found in meningococci, but not in apathogenic Neisseria sp. and Neisseria gonorrhoeae. The copy numbers of IS1301 varied between 2 and 17 per genome. IS1301 positive strains were mostly found among the serogroups 29E, W135, X, and Y. Clonal lineages of serogroup A, B, and C meningococci associated with epidemic meningococcal disease were rarely positive for IS1301.