Are Routine Urine Cultures Needed for Diabetic Dogs?

Alex Gallagher, DVM, MS, DACVIM (SAIM), Columbia Veterinary Emergency Trauma and Specialty, Columbia, South Carolina

ArticleLast Updated June 20232 min read
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In the Literature 

Nelson V, Downey A, Summers S, Shropshire S. Prevalence of signs of lower urinary tract disease and positive urine culture in dogs with diabetes mellitus: a retrospective study. J Vet Intern Med. 2023;37(2):550-555. doi:10.1111/jvim.16634 

The Research … 

Prior studies have indicated high prevalence of UTIs in dogs with diabetes mellitus (DM).1,2 Urine culture has therefore been recommended in dogs with DM, as a UTI could result in insulin resistance and contribute to poor diabetic regulation. Recent guidelines recommend not treating subclinical bacteriuria (ie, bacteriuria in the absence of clinical signs). 

In this retrospective study, prevalence of subclinical bacteriuria in dogs with DM (n = 107) was evaluated. All dogs had a paired urinalysis and urine culture. On urinalysis, 16 dogs (15%) had bacteriuria, and 8 dogs (7.5%) had pyuria. Fifteen dogs (14%) had a positive bacterial urine culture; of these, all had bacteriuria, and 8 (53.3%) had pyuria. One dog with bacteriuria had a negative culture.  

Nineteen dogs had clinical signs of lower urinary tract disease, but only 4 of the 15 dogs with a positive culture had signs of lower urinary tract disease, meaning 12.5% (11/88) of diabetic dogs without lower urinary tract signs had subclinical bacteriuria. In comparison, 16.3% (15/92) of diabetic dogs with a negative urine culture had lower urinary tract signs. 

All 11 dogs with a positive culture and no lower urinary tract signs were treated with antibiotics. Three dogs were subsequently diagnosed with subclinical bacteriuria. Of the 15 dogs with lower urinary tract signs and a negative culture, one was treated with antibiotics pending results of urine culture. Average follow-up was 3 months to 4 years; none of these 15 dogs were documented to have a UTI at the time of follow-up.  

 … The Takeaways 

Key pearls to put into practice: 

  • The current study showed lower prevalence of positive bacterial urine cultures in dogs with DM compared with prior studies. 

  • A majority of dogs with a positive urine culture had subclinical bacteriuria. Routine bacterial culture of urine in dogs with DM may therefore not be indicated in the absence of lower urinary tract signs. 

  • Dogs with DM can have lower urinary tract signs without bacterial infection. Antibiotic therapy is not indicated in these dogs without bacteriuria or a positive urine culture.