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Objectives: Characterization of non-Escherichia coli NDM-carrying Enterobacteriaceae in the poultry production environment., Methods: A total of 36 NDM-positive Enterobacteriaceae (22 Klebsiella pneumoniae, 13 Enterobacter cloacae and 1 Salmonella enterica) were isolated from a chicken farm and WGS was conducted using Illumina Hiseq2500. The genomic characterization of the isolates acquired through WGS analysis included the genomic context-flanking blaNDM genes, MLST, the antibiotic resistance genes (ARGs) and replicon types of plasmids. WGS information for another 73 K. pneumoniae isolates from different sources was retrieved from GenBank and then combined with isolates in this study for comparative genomic and phylogenetic analysis., Results: Three types of genetic environment carrying blaNDM were identified in 36 non-E. coli Enterobacteriaceae isolates. Sequence comparison analysis indicated these genetic environments were completely identical to our previous findings. WGS further revealed three major types of plasmids (IncFIB, IncX3 and IncFII) from these isolates and the phylogenetic analysis suggested several K. pneumoniae isolates with ST11, ST37 and ST147 from the commercial chicken farm that were closely related to isolates of human origin., Conclusions: The blaNDM-harbouring genetic contexts were identified not only in E. coli, but also in K. pneumoniae, E. cloacae and S. enterica, which may indicate that blaNDM has been widely disseminated to non-E. coli Enterobacteriaceae species in animal farms. The close relationship of K. pneumoniae isolates from different origins suggests they could serve as a key vehicle for the transfer of ARGs between humans and food animal production environments., (© The Author(s) 2019. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Colistin is one of the last-line drugs against difficult to treat and multidrug-resistant Gram-negative bacteria. The emergence of mobile colistin resistance gene m cr-1 increased worldwide attention on colistin resistance. mcr-1 is the dominant gene that caused resistance to colistin in chicken-derived Escherichia coli (E. coli) in China; it has a broad resistance spectrum and causes multiple drug resistance problems. There are only few studies on mcr -positive E. coli (MCRPEC) from laying ducks and quails in China. Here, the molecular and epidemiological characteristics of MCRPEC from three kinds of poultry farms (laying duck, quail, and broiler) were investigated in Changsha, China. A total of 17 mcr -positive E. coli (MCRPEC) strains were screened in 690 samples from the three kinds of poultry farms. This is the first report on MCRPEC, to our best knowledge, derived from quail. All the MCRPEC strains were resistant to colistin, sulfamethoxazole-trimethoprim, florfenicol, tetracycline, and ciprofloxacin, and mildly resistant to tigecycline, gentamicin, piperacillin/tazobactam, cefotaxime, and ceftiofur. All the strains were sensitive to meropenem and amikacin. By bioinformatics analysis, 17 MCRPEC strains belonging to 11 MLST types were distributed in phylogroups A (58.8%), B1 (23.5%), and phylogroup D (17.6%). mcr-1 was located in IncI2 plasmid with typical plasmid conjugation transfer part, type IV secretory system, and tellurium-resistant protein, increasing transmission capacity to other bacteria. Monitoring of colistin-resistant bacteria in poultry farms should be strengthened. [ABSTRACT FROM AUTHOR]