Journal of Veterinary Diagnostic Investigation 25(2) 199 –202 © 2013 The Author(s) Reprints and permission:

Urolithiasis is a common lower urinary tract problem in cats and dogs.1,5 Specific types of uroliths have been associated with bacterial urinary tract infections (UTIs).4 The associa-tion between mineral compositions and bacteria has not been recently evaluated in the past 15 years. Importantly, cultured isolates may change over time.9,11 Furthermore, previous studies did not specify if the patients were receiving antimi-crobials at the time the urolith was cultured. Uroliths can also act as a nidus for infection and can be found in dogs with recurrent UTI.13 It has been reported that bacteria isolated from the urine may differ from what is found in either the urolith or bladder mucosa; therefore, cultures of uroliths are warranted.2 In human beings, positive urolith cultures are better predictors of potential urosepsis compared to urine collected from the bladder.6 Methods describing laboratory techniques regarding urolith cultures have been reported.2,3 Oftentimes, a urolith is washed with sterile saline at least 3 or 4 times to remove any superficial bacteria that may have contaminated the stone. By convention, after the fourth wash, the wash and the core of the urolith are cultured for aerobic bacteria. Any patho-gens grown from the core of the urolith are usually reported. Other methods have described washing the urolith with alco-hol.2 Laboratory protocols for urolith cultures have not been prospectively evaluated. Therefore, the objective of the current study was to 1) ret-rospectively evaluate canine and feline urolith cultures and their association with mineral composition, signalment, urine cultures, and previous antimicrobial administration; and 2) prospectively evaluate 2 laboratory protocols for urolith cultures. Materials and methods Data collectio