High diversity of genes and plasmids encoding resistance to third-generation cephalosporins and quinolones in clinical Escherichia coli from commercial poultry flocks in Italy

Research output: Contribution to journalJournal article – Annual report year: 2018Researchpeer-review

Without internal affiliation

  • Author: Niero, Giulia

    University of Padova

  • Author: Bortolaia, Valeria

    University of Copenhagen

  • Author: Vanni, Michele

    University of Pisa

  • Author: Intorre, Luigi

    University of Pisa

  • Author: Guardabassi, Luca

    University of Copenhagen

  • Author: Piccirillo, Alessandra

    University of Padova

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The aim was to investigate occurrence and diversity of plasmid-mediated resistance to third-generation cephalosporins (3GC) and quinolones in clinical Escherichia coli from 200 industrial poultry farms across Italy. E. coli was isolated from colibacillosis lesions in turkeys (n = 109), broilers (n = 98) and layers (n = 22) between 2008 and 2012. 3GC-resistant isolates were screened for extended-spectrum and AmpC β-lactamase (ESBL/AmpC), while all isolates were tested for plasmid-mediated quinolone resistance (PMQR) genes. ESBL/AmpC- and PMQR-positive isolates were typed by pulsed-field gel electrophoresis and antimicrobial susceptibility testing, and their plasmids were characterised by replicon typing, multilocus sequence typing, restriction fragment length polymorphism and conjugation. EBSL/AmpC genes (blaCTX-M-1, blaCTX-M-14, blaCTX-M-2, blaSHV-12 and blaCMY-2) were detected in 7%, 9% and 4% of isolates from turkeys, broilers and layers, respectively. We identified seven ESBL/AmpC-encoding plasmid types, usually conjugative (78%), with a marked prevalence of IncI1/pST3 plasmids carrying blaCTX-M-1. PMQR occurred less frequently among isolates from turkeys (0.9%) compared to those from broilers (5%) and layers (4%). The PMQR genes qnrS, qnrB19 and oqxA/B were located on three plasmid types and two non-typeable plasmids, mostly (85%) conjugative. ESBL/AmpC- and PMQR-positive isolates were genetically unrelated and 64% of them were additionally resistant to aminoglycosides, sulfonamides and tetracyclines. Our data show that 3GC- and quinolone-resistant clinical E. coli in Italian poultry production represent a highly diverse population often resistant to most antimicrobials available for poultry. These findings underline the crucial need to develop new strategies for prevention and control of colibacillosis.

Original languageEnglish
JournalVeterinary Microbiology
Pages (from-to)93-98
Publication statusPublished - 1 Mar 2018
Externally publishedYes
CitationsWeb of Science® Times Cited: No match on DOI

    Research areas

  • Broiler, Clinical Escherichia coli, CMY, ESBL, Extended-spectrum cephalosporins, Fluoroquinolone, Layer, PBRT, PMQR, Turkey

ID: 146511568