Characterization and Public Health Insights of the New Delhi Metallo-β-Lactamase-Producing from Laying Hens in China.

The New Delhi metallo-β-lactamase (NDM) is a major element for the rapid expansion of the carbapenem-resistant , which poses a great challenge to public health security. NDM-producing strains (50 , 40 , and 5 ) were isolated from laying hens in China for the surveillance of antibiotic-resistant pathogens, and all were found to be multi-drug resistant bacteria. The genomic analysis of these NDM-positive bacteria revealed the ST167, ST617, and ST410 of the fifteen ST-type clones and ST37 of the four ST-type clones to be the same types as the human-derived strains. Among them, some new clone types were also found. Most of the genes ( or ) were on the IncX3 plasmids (n = 80) and were distributed in , , and , while the remaining genes were harbored in the ST167 with IncFII plasmids (n = 15). The typeⅠ1 of the eight IncX3 plasmid subtypes was consistent with the human-derived pNDM5_020001 plasmid (accession no. CP032424). In addition, these two plasmids did not affect the growth of the host bacteria and could be reproduced stably without antibiotics. Our study revealed the high genetic propensity of the NDM-positive from the laying hens and human commensal , suggesting the potentially enormous risk of its transmission to humans.