Genotypic analysis of serogroups other than A, B or C of Neisseria meningitidis in China.

To serologically and genetically characterize other serogroups (except A, B, and C) of Neisseria meningitidis isolates in China, we collected 56 strains of other serogroups, identified by serogroup typing and multilocus sequence typing (MLST). All of them are non-invasive isolates. The serogroups of the 56 Chinese isolates were W135 (11 isolates), Y (4), X (15), 29E (15), D (1), H (4), I (3), K (2), and non-groupable (1). By MLST, 34 different sequence types (STs) were identified, 28 of which were not found in the MLST database as of July 2006 and seemed to be unique to China. Statistical analysis of the MLST results revealed that, although the Chinese isolates seemed to be genetically divergent, they could be classified into 5 major clonal groups and other minor groups. Among these isolates, none of the well-documented ST complexes found worldwide was present.