Molecular Investigation of Escherichia coli Strains Associated with Apparently Persistent Urinary Tract Infection in Dogs
Version of Record online: 28 JUN 2008
© 2004 American College of Veterinary Internal Medicine
Journal of Veterinary Internal Medicine
Volume 18, Issue 3, pages 301–306, May 2004
How to Cite
Drazenovich, N., Ling, G. V. and Foley, J. (2004), Molecular Investigation of Escherichia coli Strains Associated with Apparently Persistent Urinary Tract Infection in Dogs. Journal of Veterinary Internal Medicine, 18: 301–306. doi: 10.1111/j.1939-1676.2004.tb02549.x
- Issue online: 28 JUN 2008
- Version of Record online: 28 JUN 2008
- Revised October 23, 2003; Accepted December 1, 2003.
- Antibiotic susceptibilityl;
- Polymerase chain reactionl;
- Pulsed-field gel electrophoresis
Persistent Escherichia coli urinary tract infection (UTI) in dogs is a frustrating clinical problem. Affected dogs often appear to fail to respond to therapy or to reacquire infection shortly after therapy is completed. Urovirulence factors (UVFs) of the infecting E coli, antibiotic resistance, and tissue colonization may be contributory but have not been evaluated in dogs with persistent E coli UTI. In this study, the strain types of E coli in dogs with persistent UTI were evaluated with pulsed-field gel electrophoresis (PFGE) to determine whether persistence was due to acquisition of new isolates or failure to eradicate existing isolates. UVFs in these isolates, assessed by polymerase chain reaction, and antibiograms were correlated with treatment outcome in these dogs. Results documented a mixed pattern: 9 dogs remained chronically infected with 1 or 2 strains, each with distinct reproducible UVFs, but 1 dog was infected with numerous unrelated E coli strains over time. Two dogs had a mixed pattern, consisting of 1 or more episodes of persistent E coli infection attributable to a single strain in addition to episodes caused by unrelated strains. Many isolates had no detectable UVFs, highlighting the likely importance of impaired colonization resistance in the affected dogs. Antibiotic resistance was common, often in response to previous treatments, especially with trimethoprim-sulfamethoxazole. Antibiotic resistance patterns differed significantly within PFGE strain types, suggesting lateral acquisition of resistance plasmids or integrons. These results can be used to help guide testing for and management of persistent E coli UTI in dogs.