|dc.contributor.author||Wagner, Samuel Jack Alexander||
|dc.description.abstract||This study focused on a group of multi-drug resistant (MDR) E. coli collected
between 2002 and 2011 at the Small Animal Hospital, Royal (Dick) Veterinary
School; isolated from urinary tract infections in dogs. The MDR E. coli isolates
were compared against a group of fully susceptible E. coli, also collected from
canine urinary tract infections.
The MDR isolates were notable for their AmpC β-lactamase resistance phenotype
(12/18) and resistance genotype (blaCMY-2, 8/12). Phylogenetic comparisons
between the MDR and susceptible groups of isolates showed a large degree of separation
between the two groups. Susceptible isolates strongly associated the the
pathogenic B2 phylogroup (67%), which was expected. The MDR group was
much more mixed, with isolates more associated with commensal A (28%) and
B1 (22%) phylogroups.
Virulence marker abundance, evaluated using an Identibac microarray, showed
a much reduced presence of virulence markers in the MDR group, as compared
with the susceptible isolates. An infection model, using Galleria mellonella larvae,
was used to better test the phenotypic virulence of the MDR and susceptible
E. coli isolates. An asymptomatic bacteriurea strain (ABU83972) and a virulent
pyelonephritis strain (CFT073) were used as non-virulent and virulent control
strains of uropathogenic E. coli. The model produced consistent and expected differences
in lethality between ABU8392 (non-lethal) and CFT073 (lethal) strains.
However, the model showed no differences between the MDR and susceptible
Second generation Illumina short-read sequencing and third generation single-molecule
real-time sequencing were used to further dissect the genetic background
of both the E. coli and the MDR genotype. Core-genomic sequence comparisons
of the E. coli showed no clonal relatedness amongst the different MDR and susceptible
strains. Most strikingly, sequencing revealed extensive plasmid carriage
of the MDR genotype.
Plasmid mediated blaCMY-2 was associated with a clonal group of IncI1 plasmids.
The IncI1 plasmids show favorable sequence comparisons to a plasmid
backbone previously reported in dogs and other animals, with a global distribution.
The remaining resistance genes were associated with a group of IncFII
plasmid sequences. This study highlights a broader range of commensal E. coli,
which have resulted in opportunistic infections in their canine hosts. As such,
they act as a potential reservoir of resistance, which is as yet uncharacterized.||en
|dc.contributor.sponsor||Biotechnology and Biological Sciences Research Council (BBSRC)||en
|dc.publisher||The University of Edinburgh||en
|dc.relation.hasversion||Mainda, G., Lupolova, N., Sikakwa, L., Bessell, P. R., Muma, J. B., Hoyle, D. V., McAteer, S. P., Gibbs, K., Williams, N. J., Sheppard, S. K., La Ragione, R. M., Cordoni, G., Argyle, S. A., Wagner, S., Chase-Topping, M. E., Dallman, T. J., Stevens, M. P., Bronsvoort, B. M. d., and Gally, D. L. Phylogenomic approaches to determine the zoonotic potential of shiga toxin-producing escherichia coli (stec) isolated from zambian dairy cattle. Scienti c Reports, 6: 26589 EP, 05 2016.||en
|dc.relation.hasversion||Wagner, S., Gally, D. L., and Argyle, S. A. Multidrug-resistant Escherichia coli from canine urinary tract infections tend to have commensal phylotypes, lower prevalence of virulence determinants and ampC-replicons. Veterinary microbiology, 169(3-4):17,8, mar 2014.||en
|dc.relation.hasversion||Wagner, S., Lupolova, N., Gally, D. L., and Argyle, S. A. Convergence of plasmid architectures drives emergence of multi-drug resistance in a clonally diverse escherichia coli population from a veterinary clinical care setting. Vet Microbiol, 211:6,14, Nov 2017.||en
|dc.subject||AmpC β-lactamase resistance phenotype||en
|dc.subject||reservoir of resistance||en
|dc.title||Molecular epidemiology of multi-drug resistant Escherichia coli in companion animal species||en
|dc.type||Thesis or Dissertation||en
|dc.type.qualificationname||PhD Doctor of Philosophy||en