Uropathogenic Escherichia coli of dogs and cats : pathotypic traits and susceptibility to bacteriophages : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Clinical Sciences at Massey University, Turitea, Palmerston North, Aotearoa, New Zealand

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dc.contributor.authorFreitag, Thurid
dc.date.accessioned2010-08-11T23:22:43Z
dc.date.availableNO_RESTRICTIONen_US
dc.date.available2010-08-11T23:22:43Z
dc.date.issued2006
dc.description.abstractThe purpose of this study was to investigate the feasibility of using bacteriophages - viruses that can lyse bacteria - to control infections caused by uropathogenic Escherichia coli (UPEC) in dogs and cats. Prior to phage experiments, UPEC were subjected to virulence factor genotyping by multiplex polymerase chain reaction assay and phylogenetic 'fingerprinting' by Pulsed-Field Gel Electrophoresis (PFGE). Twenty-five of 30 assessed virulence factor gene (VFG) markers were detected at least once in 31 UPEC isolated from 20 UK cats and 89 UPEC isolated from dogs (56), cats (22) and people (11) living in New Zealand (NZ). The PFGE banding patterns of UPEC isolates from different individuals were markedly dissimilar unless isolates had been collected at the same hospital within one month of each other. In contrast, ≥2 UPEC strains isolated from each of 3 UK cats diagnosed with multiple UTIs were indistinguishable by PFGE. Antibiograms inaccurtely predicted UPEC clonality and, of clinical importance, underestimated the number of relapsing or persistent infections in these cats. A comparison of VFG profiles and PFGE banding patterns of UPEC isolated from NZ and UK cats demonstrated a geographically uneven distribution of pathotypic and phylogenetic traits and indicated that, among other factors, the source of UPEC must be considered when comparing UPEC from different host species. When comparing UPEC isolates from NZ dogs, cats and people, strains with similar VFG profiles were found among the different host species. Other strains, with VFG profiles that differed according to the host species of origin were also detected. The latter finding, which is in contrast to the results of previous studies, may be of interest to researchers aiming to predict the potential zoonotic risk posed by particular UPEC strains sourced from dogs and cats. Forty bacteriophages (phages for short) were isolated from sewage waters and propagated on UPEC strains. The ability of these phages to cause bacterial lysis was tested on 31 canine UPEC, 22 feline UPEC and 7 faecal E. coli. In contrast to faecal E. coli, UPEC strains were highly susceptible to phages. Ten phages with a particularly broad host range each lysed ≥27/53 (≥51%) UPEC strains. Used in combination, these 10 phages were predicted to be able to lyse 49/53 (92%) of the UPEC strains in the collection. Morphological and genotypic studies on 5 of these 10 phages demonstrated that 4 of them belonged to the lytic T4-like genus, while one phage showed similarity to the temperate phage P2. Overall, results of this project indicate that the majority of canine and feline UPEC - with very diverse PFGE banding patterns and VFG profiles - are susceptible to lysis by naturally occurring phages. Hence, phages show promise as therapeutic agents for treatment of canine and feline UTI and, perhaps, for other infections caused by UPEC.en_US
dc.identifier.urihttp://hdl.handle.net/10179/1541
dc.language.isoenen_US
dc.publisherMassey Universityen_US
dc.rightsThe Authoren_US
dc.subjectPhagesen_US
dc.subjectPhylogenyen_US
dc.subjectUPEC strainsen_US
dc.subject.otherFields of Research::300000 Agricultural, Veterinary and Environmental Sciences::300500 Veterinary Medicine::300510 Virologyen_US
dc.titleUropathogenic Escherichia coli of dogs and cats : pathotypic traits and susceptibility to bacteriophages : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Clinical Sciences at Massey University, Turitea, Palmerston North, Aotearoa, New Zealanden_US
dc.typeThesisen_US
massey.contributor.authorFreitag, Thurid
thesis.degree.disciplineVeterinary Clinical Scienceen_US
thesis.degree.grantorMassey Universityen_US
thesis.degree.levelDoctoralen_US
thesis.degree.levelDoctoralen
thesis.degree.nameDoctor of Philosophy (Ph.D.)en_US
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