Whole genome sequencing for tracking the global bacterial transmission scenarios of four representative bacterial species A. baumannii (A), E. coli (B), S. enterica (C) and V. cholera (D). The geographical locations of all of these closely related isolates (differing from one another by <10 loci) were pinpointed on geographic maps, and the topologies of the lines connecting these isolates follows a minimum spanning tree, constructed based on cgMLST analysis. The digital numbers on the lines illustrate the number of allelic differences, while the collection years are color coded and listed to the right of the circles. The right minimum spanning tree was constructed for the control isolates, which were collected from a single site (symbolized as a red pentagram on each left-side map).