Prevalence and risk factors of antimicrobial resistance in canine urinary infections

Thesis Abstract

The rise of antimicrobial resistance (AMR) in canine urinary infections poses a significant threat to veterinary clinical outcomes and public health, driven by inappropriate antimicrobial use, ecological factors, and canine microbiota dynamics. This study addresses the persistent gap in regionally representative data on AMR prevalence and the multifactorial risk factors that drive resistant infections in the urinary tract of dogs. The aim is to determine the prevalence of antimicrobial-resistant pathogens in canine urinary infections and to identify patient-level, environmental, and management factors associated with AMR. Specific objectives include (i) estimating the prevalence of bacterial isolates resistant to key veterinary antibiotics (?-lactams, fluoroquinolones, tetracyclines, and aminoglycosides); (ii) characterising species distribution and resistance profiles of isolates; (iii) assessing associations between host factors (age, sex, breed, comorbidities), clinical history (previous antibiotic exposure, hospitalization, prior urinary tract infection), and AMR; (iv) evaluating the influence of veterinary practice characteristics (clinic type, antimicrobial stewardship policies) on AMR risk; and (v) informing empirical treatment guidelines and stewardship interventions. The theoretical framework integrates the eco-social model of AMR, the One Health concept, and Ajzen’s Theory of Planned Behavior to explain how provider prescribing patterns, owner adherence, and animal health status interact to shape resistance trajectories. A cross-sectional, multicenter design will be adopted across 12 veterinary clinics and two referral hospitals over 12 months, targeting canine patients presenting with signs of urinary tract infection. A purposive sampling strategy aims to enroll a minimum of 400 dogs with confirmed bacteriuria or suspected infection, from which urine cultures will yield bacterial isolates for antimicrobial susceptibility testing (AST) using standardized disk diffusion and broth microdilution methods following CLSI guidelines. Data collection will integrate laboratory results with a structured clinical data form capturing demographics, clinical presentation, prior antimicrobial exposure (within the last 6 months), hospitalization history, urine sampling method, comorbidities, and treatment outcomes. To ensure data quality, instrument validity will be assessed through pilot testing in 20 cases, and reliability will be evaluated using inter-rater agreement for clinical data abstraction. Multivariable logistic regression will identify risk factors for any resistant infection, with antibiotic resistance as the dependent variable and covariates including prior antibiotic exposure, hospitalization, age, comorbidities, and clinic stewardship practices. Secondary analyses will examine species-specific resistance patterns using multinomial logistic regression and explore interaction effects between prior antibiotic exposure and recent hospitalization. Descriptive statistics will summarise prevalence, species distribution, and resistance profiles. It is anticipated that overall AMR prevalence will exceed 20%, with higher resistance observed to fluoroquinolones and ?-lactams among Escherichia coli and Klebsiella spp., and that recent antibiotic exposure and hospital-based care will be significant risk factors. The study is expected to reveal gaps in current empirical therapy, highlight the impact of antimicrobial stewardship practices at clinics, and provide a basis for targeted interventions. The anticipated contribution includes robust, regionally relevant estimates of AMR prevalence in canine urinary infections, identification of modifiable risk factors to inform clinical decision-making, and evidence to support policy development for prudent antibiotic use in companion animals. The main conclusion will emphasize the necessity of integrated stewardship strategies combining routine surveillance, provider education, and owner engagement to reduce AMR in canine urinary pathogens. Recommendations will include standardized diagnostic workflows, restricted use of critically important antimicrobials, implementation of antibiogram-guided empiric therapy, and continued surveillance through a centralized canine urinary AMR database to monitor trends and evaluate the impact of stewardship initiatives.