Prevalence of positive urine culture in the presence of inactive urine sediment in 1049 urine samples from dogs

BACKGROUND: Urinalysis (UA) is often used to screen for bacterial cystitis, regardless of sediment results, and followed up by quantitative urine culture (UC) for definitive diagnosis. OBJECTIVES: Determine prevalence of positive UCs in dogs with inactive urine sediments on routine UA. ANIMALS: A total of 1049 urine samples with inactive urine sediments and UCs collected from dogs presented to a veterinary specialty hospital between January 2018 and February 2020. METHODS: Retrospective study of dogs with an inactive urine sediment on routine UA and follow‐up UCs. Signalment, UA findings, proteinuria, and UC results were recorded. Associations among these findings were assessed using multivariate logistic regression carried out using a backward stepwise method. RESULTS: Overall prevalence of positive UC was 3.4% (95% confidence interval [CI], 2.4‐4.8). Escherichia coli was the most commonly isolated bacteria. Only naturally voided samples were associated with increased prevalence of positive culture when compared to collection by cystocentesis or a non‐specified method. No statistically significant association with culture positivity was found for urine protein‐to‐creatinine ratio, urine specific gravity, urine pH, breed, age, or sex. CONCLUSIONS AND CLINICAL IMPORTANCE: Based on the low prevalence (3.4%) of positive culture in urine samples from dogs with inactive sediment on routine UA and the relatively high cost of UC and sensitivity, cost‐benefit analysis including clinical suspicion of lower urinary tract disease should inform testing decisions, rather than routinely performing cultures on urine samples without active sediments.