title: Complete genetic analysis of plasmids carrying mcr-1 and other resistance genes in an Escherichia coli isolate of animal origin.
abstract: To investigate the genetic features of three plasmids recovered from an MCR-1 and ESBL-producing Escherichia coli strain, HYEC7, and characterize the transmission mechanism of mcr-1 .
  
  
  
  The genetic profiles of three plasmids were determined by PCR, S1-PFGE, Southern hybridization and WGS analysis. The ability of the mcr-1 -bearing plasmid to undergo conjugation was also assessed. The mcr-1 -bearing transposon Tn 6330 was characterized by PCR and DNA sequencing.
  
  
  
  Complete sequences of three plasmids were obtained. A non-conjugative phage P7-like plasmid, pHYEC7- mcr1 , was found to harbour the mcr-1 -bearing transposon Tn 6330 , which could be excised from the plasmid by generating a circular intermediate harbouring mcr-1 and the IS Apl1 element. The insertion of the circular intermediate into another plasmid, pHYEC7-IncHI2, could form pHNSHP45-2, the original IncHI2-type mcr-1 -carrying plasmid that was reported. The third plasmid, pHYEC7-110, harboured two replicons, IncX1 and IncFIB, and comprised multiple antimicrobial resistance mobile elements, some of which were shared by pHYEC7-IncHI2.
  
  
  
  The Tn 6330 element located in the phage-like plasmid pHYEC7- mcr1 could be excised from the plasmid and formed a circular intermediate that could be integrated into plasmids containing the IS Apl1 element. This phenomenon indicated that Tn 6330 is a key element responsible for widespread dissemination of mcr-1 among various types of plasmids and bacterial chromosomes. The dissemination rate of such an element may be further enhanced upon translocation into phage-like vectors, which may also be transmitted via transduction events.
authors.affiliation: Shenzhen Key Lab for Food Biological Safety Control, Food Safety and Technology Research Center, Hong Kong PolyU Shen Zhen Research Institute, Shenzhen, P. R. China.|The State Key Lab of Chirosciences, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR.
authors.forename: Ruichao
authors.initials: R
authors.lastname: Li
authors.affiliation: Shenzhen Key Lab for Food Biological Safety Control, Food Safety and Technology Research Center, Hong Kong PolyU Shen Zhen Research Institute, Shenzhen, P. R. China.
authors.forename: Miaomiao
authors.initials: M
authors.lastname: Xie
authors.affiliation: Division of Food Inspection and Supervision, Shenzhen Entry-Exit Inspection and Quarantine Bureau of the People's Republic of China, Shenzhen, P. R. China.
authors.forename: Jingzhang
authors.initials: J
authors.lastname: Lv
authors.affiliation: The State Key Lab of Chirosciences, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR.
authors.forename: Edward
authors.initials: E
authors.lastname: Wai-Chi Chan
authors.affiliation: Shenzhen Key Lab for Food Biological Safety Control, Food Safety and Technology Research Center, Hong Kong PolyU Shen Zhen Research Institute, Shenzhen, P. R. China.|The State Key Lab of Chirosciences, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR.
authors.forename: Sheng
authors.initials: S
authors.lastname: Chen
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002876:Chromosomes, Bacterial / Q000235:genetics*; D003227:Conjugation, Genetic; D004251:DNA Transposable Elements / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology* / Q000635:transmission; D029968:Escherichia coli Proteins / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods; D017422:Sequence Analysis, DNA / Q000379:methods; D001618:beta-Lactamases / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C000614037:MCR-1 protein, E coli; D001618:beta-Lactamases