Diverse flanking sequence types of blaNDM in IncX3 and IncB/O/K/Z plasmids in Escherichia coli isolated from poultry

Abstract

We identified 33 blaNDM-harboring Escherichia coli in 470 poultry samples from Shandong and Guangdong provinces during 2016 to 2017 and included the subtypes blaNDM-1, blaNDM-5 and blaNDM-9. The blaNDM gene possessed by all strains was plasmid-borne and ranged in size from 46 to 265 kb. The plasmids included the replicon types IncX3, IncY, IncB/O/K/Z and IncHI2 and most were transferable and stable in recipient host bacteria. Sequences flanking blaNDM in IncX3 and IncB/O/K/Z plasmids were diverse and the mobile element IS26 played an important role in the evolution of the IncB/O/K/Z blaNDM plasmids.