Urinary tract infections in dogs with spontaneous hypercortisolism - frequency, symptoms and involved pathogens.

Dogs with hypercortisolism are predisposed to developing bacteriuria associated either with clinical signs of cystitis or without clinical signs (subclinical bacteriuria). Based on current guidelines, dogs with subclinical bacteriuria should not be treated with antibiotics because there is no evidence that treatment improves outcome and because unnecessary treatments should be avoided. Before these guidelines were published in 2019, dogs with hypercortisolism and bacteriuria were commonly treated with antibiotics irrespective of clinical signs. Comprehensive data on the frequency of bacterial cystitis, subclinical bacteriuria and the outcome of antimicrobial treatment in dogs with hypercortisolism is sparse. The aims of this study were to investigate dogs with hypercortisolism for the presence of bacterial cystitis and subclinical bacteriuria, to address the pathogens involved, and to assess the outcome of antibiotic treatment. Dogs newly diagnosed with hypercortisolism between 2005 and 2015 from which a urine bacterial culture was available were included. Statistical analysis was performed with non-parametric tests. Of the 161 client-owned dogs included, 29 (18%) showed bacteriuria, which was subclinical in 24 (83%) cases. Escherichia coli was the most commonly isolated pathogen (58%). Bacteriuria was not associated with sex or neutering status. In 14 dogs, follow-up data was available, of which 13 (93%) were treated with antimicrobials for 14 to 28 days. Follow-up bacterial culture (1 to 118 days after cessation of therapy) was negative in 10 (77%) treated dogs; a negative follow-up culture was not associated with gender, age or duration of treatment. Bacteriuria persisted in three treated dogs and the one untreated dog. The prevalence of positive bacterial urinary culture in dogs with hypercortisolism was lower than previously reported. In the majority of dogs, bacteriuria was subclinical. Most dogs had a negative bacterial culture result after antimicrobial treatment; however, more resistant bacteria were detected in persistently positive urine.