The prevalence and potential mobility of Tn21-like mercury resistance transposons in E. coli isolated from dairy cattle slurry

Iles, Ethan (2019) The prevalence and potential mobility of Tn21-like mercury resistance transposons in E. coli isolated from dairy cattle slurry. MRes thesis, University of Nottingham.

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Abstract

The risk of antimicrobial resistance as well as antimicrobial resistant infections arising from agricultural environments is widely debated. Through the movement and acquisition of plasmids, which carry complex and varying resistance gene cassettes, there is an undeniable rise in resistances occurring across the world though the impact of this movement needs to be evaluated.

A total of 926 E. coli isolates that had been cultured from slurry samples and from the slurry tank on the Sutton Bonington dairy unit using Tryptone-Bile X-glucuronide (TBX) growth media with or without cefotaxime, or isolated using CHROMagar ESBL media, were tested for mercury and antibiotic resistance. Seven E. coli isolates were phenotypically mercury resistant and confirmed by PCR to carry merA, merC, merR and intI, suggesting they carried a Tn21-like transposon. All isolates were tested for phenotypic resistance to 21 antibiotics representing 15 antibiotic classes. All the isolates found to be mercury resistant were found to be resistant to at least 4 antibiotics, with 2 isolates taken from the slurry tank being resistant to 6 antibiotics and those taken from the muck heap being resistant to 4.

Potential mobility of the Tn21 like transposons was determined using transposon trapping using RP4-8 using gentamicin resistance as a phenotypic marker. Only two of the isolates out of seven showed transposons which were able to move into RP4-8 and then into E. coli K12 MG6155 strains.

Item Type: Thesis (University of Nottingham only) (MRes)
Supervisors: Hobman, Jon
Dodd, Christine
Keywords: antimicrobial resistance, plasmids, dairy cattle, transposons
Subjects: Q Science > QR Microbiology > QR 75 Bacteria. Cyanobacteria
S Agriculture > SF Animal culture
Faculties/Schools: UK Campuses > Faculty of Science > School of Biosciences
Item ID: 56658
Depositing User: Iles, Ethan
Date Deposited: 13 Sep 2023 12:20
Last Modified: 13 Sep 2023 12:20
URI: https://eprints.nottingham.ac.uk/id/eprint/56658

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