title: Complete sequences of IncHI1 plasmids carrying blaCTX-M-1 and qnrS1 in equine Escherichia coli provide new insights into plasmid evolution.
abstract: OBJECTIVE
  To determine the structure of two multidrug-resistant IncHI1 plasmids carrying blaCTX-M-1 in Escherichia coli isolates disseminated in an equine clinic in the Czech Republic.
  
  
  METHODS
  A complete nucleotide sequencing of 239 kb IncHI1 (pEQ1) and 287 kb IncHI1/X1 (pEQ2) plasmids was performed using the 454-Genome Sequencer FLX system. The sequences were compared using bioinformatic tools with other sequenced IncHI1 plasmids.
  
  
  RESULTS
  A comparative analysis of pEQ1 and pEQ2 identified high nucleotide identity with the IncHI1 type 2 plasmids. A novel 24 kb module containing an operon involved in short-chain fructooligosaccharide uptake and metabolism was found in the pEQ backbones. The role of the pEQ plasmids in the metabolism of short-chain fructooligosaccharides was demonstrated by studying the growth of E. coli cells in the presence of these sugars. The module containing the blaCTX-M-1 gene was formed by a truncated macrolide resistance cluster and flanked by IS26 as previously observed in IncI1 and IncN plasmids. The IncHI1 plasmid changed size and gained the quinolone resistance gene qnrS1 as a result of IS26-mediated fusion with an IncX1 plasmid.
  
  
  CONCLUSIONS
  Our data highlight the structure and evolution of IncHI1 from equine E. coli. A plasmid-mediated sugar metabolic element could play a key role in strain fitness, contributing to the successful dissemination and maintenance of these plasmids in the intestinal microflora of horses.
authors.affiliation: Department of Biology and Wildlife Diseases, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Palackeho tr. 1/3, 612 42 Brno, Czech Republic CEITEC VFU, University of Veterinary and Pharmaceutical Sciences Brno, Palackeho tr. 1/3, 612 42 Brno, Czech Republic m.dolejska@centrum.cz.
authors.forename: Monika
authors.initials: M
authors.lastname: Dolejska
authors.affiliation: Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Villa
authors.affiliation: Department of Veterinary Disease Biology, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg C, Denmark.
authors.forename: Marco
authors.initials: M
authors.lastname: Minoia
authors.affiliation: Department of Veterinary Disease Biology, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg C, Denmark.
authors.forename: Luca
authors.initials: L
authors.lastname: Guardabassi
authors.affiliation: Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Carattoli
mesh_terms: D000818:Animals; D018153:Czech Republic; D004926:Escherichia coli / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary*; D029968:Escherichia coli Proteins / Q000235:genetics; D019143:Evolution, Molecular; D023061:Gene Order; D006736:Horses; D053858:Metabolic Networks and Pathways / Q000235:genetics; D008969:Molecular Sequence Data; D010957:Plasmids; D017422:Sequence Analysis, DNA; D026801:Synteny; D001618:beta-Lactamases / Q000235:genetics
chemical_list: D029968:Escherichia coli Proteins; C485384:Qnr protein, E coli; C055184:beta-lactamase TEM-3; D001618:beta-Lactamases
keywords: CTX-M-1; IncHI1; IncX1; fructooligosaccharides; horses