FIG. 5.

ET dendrogam showing the distribution of different exl cassettes in the meningococcal population represented by 97 ETs. The carriage of hmbR (stippled boxes), exl2 (black boxes), and exl3 or exl3A (hatched boxes) in 92 ET isolates is shown to the left of the dendrogram. The ET designations appear on the y axis in the following manner: serogroup/ET type, where serogroup is represented by the single-letter code (A, B, C, Y, W [W-135], Z, and NG [nongroupable]) and ET type is represented by the four-digit numerical code. All of the representative strains from each ET type are clinical isolates, except for those labeled with an asterisk, indicating isolation from the nasopharynx of an asymptomatic carrier. ET complexes or clonal groups are boxed in grey and are labeled accordingly. The ET clonal groups ET5 and ET17-ET24 and subgroups I, II, III, IV-1, V, VI, VII, and VIII have been described elsewhere (2). The clonal complexes ET501-ET508, A, and B are described in this study.