@article{mbs:/content/journal/jmm/10.1099/jmm.0.062729-0, author = "Ingram, Paul Robert and Rogers, Benjamin A. and Sidjabat, Hanna E. and Gibson, Justine S. and Inglis, Timothy J. J.", title = "Co-selection may explain high rates of ciprofloxacin non-susceptible Escherichia coli from retail poultry reared without prior fluoroquinolone exposure", journal= "Journal of Medical Microbiology", year = "2013", volume = "62", number = "11", pages = "1743-1746", doi = "https://doi.org/10.1099/jmm.0.062729-0", url = "https://www.microbiologyresearch.org/content/journal/jmm/10.1099/jmm.0.062729-0", publisher = "Microbiology Society", issn = "1473-5644", type = "Journal Article", abstract = "Australia has never permitted fluoroquinolone use in food-producing animals. We examined local retail poultry for contamination with fluoroquinolone non-susceptible Escherichia coli, then explored the hypothesis that their presence may be due to co-selection of resistance determinants. Between August and November 2010, samples from 30 locally produced, uncooked retail poultry carcasses from four different processing centres underwent selective enrichment culture for ciprofloxacin non-susceptible E. coli. Their chromosomal- and plasmid-mediated resistance determinants were characterized, and phylogenetic analysis and transformation experiments were performed. Unexpectedly, we found nine (30 %) of our small collection of poultry samples carried fluoroquinolone non-susceptible E. coli of which nearly half possessed aac(6')-Ib-cr, a novel plasmid-mediated gene encoding an aminoglycoside acetylating enzyme that also confers fluoroquinolone resistance. All nine isolates were co-resistant to amoxicillin, gentamicin, tetracycline and trimethoprim/sulfamethoxazole – all antibiotic classes that are registered for use in poultry reared for food production within Australia. Their unique phylogenetic relatedness suggested clonal dissemination driven by non-fluoroquinolone selective pressures. aac(6')-Ib-cr was successfully transformed and selected for using non-fluoroquinolone antibiotic pressure. Vertical and perhaps horizontal co-selection may be contributing to the emergence of fluoroquinolone resistance in poultry and could play a similar role in the human setting. This suggests that preservation of the usefulness of fluoroquinolones may require more than just restriction of their use in isolation from other interventions.", }