Characteristics of ciprofloxacin and cephalosporin resistant Escherichia coli isolated from turkeys in Great Britain |
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| Authors: | LP Randall D Mueller-Doblies FL Lemma RA Horton CJ Teale RH Davies |
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| Institution: | Animal Health and Veterinary Laboratories Agency (Weybridge) , New Haw, Addlestone, Surrey , KT15 3NB , United Kingdom |
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| Abstract: | 1. A field study was performed to investigate the presence and characteristics of ciprofloxacin-resistant, extended spectrum β-lactamase (ESBL) and AmpC Escherichia coli from turkeys in Great Britain. E. coli were isolated from ～9000 boot swab samples from 27 different farms owned by four different companies. Between 1 and 14 visits were made to each farm (mean 3) at between 0 and 15?m intervals (mean?～?5?m). 2. CHROMagar ECC with and without ciprofloxacin or cephalosporin antibiotics was used as selective isolation media. Representative isolates with different phenotypes were tested for mutations in gyrA and for: qnrA, B, S, qepA and aac(6′)-Ib genes, for ESBL phenotype, the presence of bla CTX-M genes and plasmid type, and for ampC genes. Representative ciprofloxacin-resistant and CTX-M isolates were further tested for serotype and PFGE type. On ciprofloxacin selective media 55% of samples yielded ciprofloxacin resistant E. coli and of those further analysed, most had ciprofloxacin MICs >4 mg/l and mutations in gyrA. 3. For the different companies, the mean number of samples per farm with cefoxitin- or cefotaxime-resistant isolates ranged from 1·0% to 61·9% and 4·7% to 31·7% respectively. Cefotaxime-resistance was most commonly associated with an ESBL phenotype, a CTX-M-1 or CTX-M-14 sequence type and an I1-γ or K plasmid inc type. The mechanism of cefoxitin resistance was not determined for most isolates, but where determined it was bla CMY-2. 4. PFGE and serotyping showed clonally-related isolates persisting over multiple visits suggesting both more prudent use of antibiotics and improved farm hygiene are needed to address the issue of antimicrobial resistance in isolates from turkeys. |
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