Fig. 1

The minimum spanning tree based on the STs of all pks+ strains (n = 171). The end of the bars were the corresponding STs. The four colored shaded circles represent different clonal complexes (CCs): CC12 (green), CC14 (light green), CC73 (blue), and CC95 (red). The length of the bar represents the quantity of strains for STs. The red parts of the bars of ST12, ST141, ST73, ST95, ST12 (orange), ST8303 (orange) represent the strains isolates from ulcerative colitis (UC) patients