Introduction: Emergence of resistance determinants of blaNDM and mcr-1 has undermined the antimicrobial effectiveness of the last line drugs carbapenems and colistin. Aim: This work aimed to assess the prevalence of blaNDM and mcr-1 in E. coli strains collected from food in Shenzhen, China, during the period 2015 to 2017. Methods: Multidrug-resistant E. coli strains were isolated from food samples. Plasmids encoding mcr-1 or blaNDM genes were characterised and compared with plasmids found in clinical isolates.ResultsAmong 1,166 non-repeated cephalosporin-resistant E. coli strains isolated from 2,147 food samples, 390 and 42, respectively, were resistant to colistin and meropenem, with five strains…
Four Enterobacteriaceae clinical isolates bearing mcr-1 gene-harboring plasmids were characterized. All isolates demonstrated the ability to transfer colistin resistance to Escherichia coli; plasmids were stable in conjugants after multiple passages on nonselective media. mcr-1 was located on an IncX4 (n?=?3) or IncN (n?=?1) plasmid. The IncN plasmid harbored 13 additional antimicrobial resistance genes. Results indicate that the mcr-1-bearing plasmids in this study were highly transferable in vitro and stable in the recipients.This is a work of the U.S. Government and is not subject to copyright protection in the United States. Foreign copyrights may apply.
IS26-flanked transposons played an increasingly important part in the mobilization and development of resistance determinants. Heterogeneous resistance-encoding plasmid clusters with polymorphic MDR regions (MRRs) conferred by IS26 in an individual Escherichia coli isolate have not yet been detected.To characterize the complete sequence of a novel blaCTX-M-65- and fosA3-carrying IncZ-7 plasmid with dynamic MRRs from an E. coli isolate, and to depict the mechanism underlying the spread of resistance determinants and genetic polymorphisms.The molecular characterization of a strain carrying blaCTX-M-65 and fosA3 was analysed by antimicrobial susceptibility testing and MLST. The transferability of a plasmid bearing blaCTX-M-65 and fosA3 was determined…
Colistin resistance mediated by mcr-1-harbouring plasmids is an emerging threat in Enterobacteriaceae, like Salmonella. Based on its major contribution to the diarrhoea burden, the epidemic state and threat of mcr-1-harbouring Salmonella in community-acquired infections should be estimated.This retrospective study analysed the mcr-1 gene incidence in Salmonella strains collected from a surveillance on diarrhoeal outpatients in Shanghai Municipality, China, 2006-2016. Molecular characteristics of the mcr-1-positive strains and their plasmids were determined by genome sequencing. The transfer abilities of these plasmids were measured with various conjugation strains, species, and serotypes.Among the 12,053 Salmonella isolates, 37 mcr-1-harbouring strains, in which 35 were serovar…