Genetic relationships of the isolates based on MLST. A) The minimum spanning tree of the 36 STs from China. Each circle corresponds to a sequence type. The shadow zones in different color correspond to different clonal complexes. The size of the circle is proportional to the number of the isolates, and the color within the cycles represents the serotypes of the isolates. B) Neighbor-joining tree of L. monocytogenes sequence types constructed using the concatenate sequences of seven housekeeping genes. Listeria innocua was used as an outgroup. Lineages are marked on both trees which were shown using dotted boundary lines in A.