Prevalence of individual bacterial uropathogens isolated from urine samples of dogs and cats and the relationship between a positive urine culture and the presence of organic, inorganic elements and proteins in the urine

Clinical signs of lower urinary tract inflammation are common in domestic carnivores. In dogs, they are usually the result of a bacterial infection, while in cats, they are more often caused by sterile inflammation or behavioural disorders. The prevalence of individual bacterial pathogens isolated from urine samples of dogs and cats was determined, and the relationship between a positive urine culture and the presence of organic and inorganic elements, and proteins was investigated. From January 2022 to June 2024, a total of 563 dog urine samples and 86 cat urine samples were analysed in the Split branch of the Laboratory for Diagnostics, Croatian Veterinary Institute. A clinically significant number of bacteria were isolated from 196 of 563 (34.81%) dog urine samples and 21 of 86 (24.41%) cat urine samples. Of the total number of bacterial isolates, 141 (64.4%) were gram-negative and 78 (35.6%) were gram-positive. Escherichia coli was the most common isolate (45.9% in dogs, 33.3% in cats). In dogs, the second most common isolates were Staphylococcus spp. (20.9%), Streptococcus spp. (9.2%), Proteus spp. (7.7%), Enterococcus spp. (4.6%), Klebsiella spp. (4.08%), and Pseudomonas spp. (3.6%), while other bacterial isolates were <2%. In cats, the most frequently isolated bacteria were Proteus spp. (23.8%), Pseudomonas spp. (14.3%), Streptococcus and Enterococcus spp. (9.5% each), and Staphylococcus spp. and Pasteurella spp. (4.8% each). In dogs, a significant and positive correlation was found between a positive bacteriological result and pyuria, haematuria, proteinuria, and age. In cats, no significant correlations were found between a positive bacteriological culture and variables such as pyuria, haematuria, proteinuria, crystals, or animal age or sex.