Journal of Medical Microbiology (2004), 53, 657–662 DOI 10.1099/jmm.0.45541-0 45541 & 2004 SGM Printed in Great Britain 657 Correspondence

Analysis of 182Neisseria meningitidis strains isolated over the past 30 years in Japan by serogroup typing andmultilocus sequence typing (MLST)wasperformed. The serogroups of the 182 Japanese isolates were B (103 isolates), Y (39), W135 (1) and non-groupable (39). By MLST analysis, 65 different sequence types (ST) were identified, 42 of which were not found in the MLST database as of January 2004 and seemed to be unique to Japan. Statistical analysis of theMLST results revealed that, although the Japanese isolates seemed to be genetically divergent, they were classified into six major clonal complexes and other minor complexes. Among these isolates, well-documented ST complexes foundworldwidewere present, such asST-23 complex (49 isolates), ST-44complex (41 isolates) and ST-32 complex (8 isolates). On the other hand, a new clonal complex designated ST-2046 complex (28 isolates), which has not been identified in other countries, was also found, suggesting that this clone was indigenous to Japan. Taken together, it was speculated that meningococcal isolates in Japan comprised heterogeneous clones, which were derived both from clones identified in other countries and clones unique to Japan