Spread of Clonally Related Escherichia coli Strains Harboring an IncA/C Plasmid Encoding IMP-8 and Its Recruitment into an Unrelated MCR-1-Containing Isolate.

Ten IMP-8-producing isolates were recovered from surveillance cultures of a neonatal intensive care unit; eight of the isolates were clonally related. A 168.2-kb plasmid was fully sequenced, and it corresponded to the recently described IncA/C1-ST13 plasmid. This plasmid was detected in all isolates, even in those that were not clonally related. One unrelated isolate was also resistant to colistin and positive for This marker was located in a 62.7-kb IncI2 plasmid, which was also fully sequenced.