“…We identified 33 plasmid Inc types among all isolates, and the results showed that the most common Inc type was IncFIB(K) (45.8%, n = 22), followed by IncColRNAI (43.8%, n = 21), IncHI1 (33.3%, n = 16), IncX1 (31.3%, n = 15), IncFIB (AP001918) (27.1%, n = 13), and IncY (20.8%, n = 10). Remarkably, the common Inc types of mcr - 1 -harboring plasmids, such as IncX4, IncI2, IncHI2, and IncpO111 [ 1 , 3 , 4 , 12 ], were rarely detected among these isolates (Fig. 1 ), indicating that the chromosomally-encoded mcr - 1 may derive from IS Apl1 /Tn 6330 through transposition, but not from the plasmid.…”