Article of the Week


We will be posting commentaries on articles relating to internal medicine and endocrinology that we think are of interest.


November 23rd, 2021

Evaluation of antimicrobial prescriptions in dogs with suspected bacterial urinary tract disease


Infectious urinary tract disease is commonly diagnosed in dogs and accounts for abundant antimicrobial use. Both lower (eg, cystitis) and upper (pyelonephritis) urinary tract disease can be encountered and empirical treatment decisions are typically made when initiating antimicrobial treatment. The dearth of high level evidence comparing different treatment regimens complicates antimicrobial selection in companion animals. Properly designed randomized clinical trials, which provide the highest level of evidence, are scarce. Increasingly, there is interest in national or international clinical practice guidelines, akin to what is available in human medicine. While currently driven by expert opinion, veterinary guidelines, based on data from companion animals, data from other species and general principles of microbiology, pharmacology, infectious diseases, and internal medicine can provide guidance to practitioners and improve clinical care in the absence of high level data. In 2011, International Society for Companion Animal Infectious Diseases (ISCAID) guidelines for the diagnosis and treatment of bacterial urinary tract disease were released, with an updated version released in 2019. The impact of guidelines has not been properly evaluated and is difficult to study.


Antimicrobial stewardship is an area that is getting increasing attention in veterinary and human medicine, as the magnitude and scope of antimicrobial resistance become clear. Antimicrobial resistance is also a One Health problem that requires study of all components of the One Health triad—humans, animals, and the environment. Antimicrobial use in any area can contribute to resistance, with resistant bacteria and resistance genes moving among animals, humans, and the environment. Antimicrobial stewardship aims to optimize antimicrobial therapy, maximizing clinical outcomes while minimizing adverse effects on the patient (eg, gastrointestinal complications) or population (eg, selection pressure for antimicrobial resistance). Concerns about the public health impacts of antimicrobial use in animals add more pressure to optimize use of antimicrobials in all species. A core component of antimicrobial stewardship is improved understanding of when and how antimicrobials are used.


Understanding antimicrobial use patterns is critical for determining potential areas for improvement and intervention, and to facilitate an evidence-based approach to stewardship activities. Establishment of baseline rates (benchmarking) is necessary for comparisons and to evaluate the impact of interventions. The objective of this multicenter study was to evaluate initial antimicrobial therapy in dogs diagnosed with upper or lower urinary tract infections.


Background: Antimicrobials are commonly used to treat urinary tract disease in dogs. Understanding antimicrobial use is a critical component of antimicrobial stewardship efforts.


Hypothesis/Objectives: To evaluate antimicrobial prescriptions for dogs diagnosed with acute cystitis, recurrent cystitis, and pyelonephritis.


Animals: Dogs prescribed antimicrobials for urinary tract disease at veterinary practices in the United States and Canada.


Materials and Methods: A retrospective review of antimicrobial prescriptions was performed.


Results: The main clinical concerns were sporadic bacterial cystitis (n = 6582), recurrent cystitis (n = 428), and pyelonephritis (n = 326). Amoxicillin/clavulanic acid (2702, 41%), cefpodoxime (1024, 16%), and amoxicillin (874, 13%) were most commonly prescribed for sporadic bacterial cystitis. The median prescribed duration was 12 days (range, 3-60 days; interquartile range [IQR], 4 days). Shorter durations were used in 2018 (median, 10 days; IQR, 4 days) compared to both 2016 and 2017 (both median, 14 days; IQR, 4 days; P ≤ .0002). Amoxicillin/clavulanic acid (146, 33%), marbofloxacin (95, 21%), and cefpodoxime (65, 14%) were most commonly used for recurrent cystitis; median duration of 14 days (range, 3-77 days; IQR, 10.5 days). Amoxicillin/clavulanic acid (86, 26%), marbofloxacin (56, 17%), and enrofloxacin (36, 11%) were most commonly prescribed for pyelonephritis; however, 93 (29%) dogs received drug combinations. The median duration of treatment was 14 days (range, 3-77 days; IQR, 11 days).


Conclusions and Clinical Importance: Decreases in duration and increased use of recommended first-line antimicrobials were encouraging. Common drug choices and durations should still be targets for antimicrobial stewardship programs that aim to optimize antimicrobial use, concurrently maximizing patient benefits while minimizing antimicrobial use and use of higher tier antimicrobials.