Minimum spanning tree showing the MLST pattern of 392 Chlamydia trachomatis positive anorectal samples from MSM and women. Each circle represents one ST. Size of the circles is proportional to the number of identical ST profiles. Bold lines connect types that differ for one single locus. Halos indicate the distinct clusters. The color coding is: green, men who have sex with men (n = 207); red, heterosexual women (n = 185).