Figure 2. Minimum spanning tree showing the sexual orientation of the host of 526 Chlamydia trachomatis-positive samples from MSM and heterosexuals in Amsterdam between July 2008 and May 2010.

Sizes of the node discs are proportional to the number of samples of each sequence type; branches show single locus variants (SLV); halos indicate clusters based on SLV; and letters indicate ompA genovar type. The color coding is: pink, men who have sex with men only (n = 262); green, men who have sex with men and women (n = 8); and blue, heterosexual men and women (n = 256).