CHARACTERIZATION OF 127 URINARY SAMPLES IN DOGS WITH URINARY TRACT INFECTIONS: A RETROSPECTIVE STUDY (2015 -2018)

Uncomplicated canine bacterial urinary tract infection (UTI) commonly occurring in approximately 14 % of dogs over its lifetime. Persistent or recurrent infections, including refractory bacteria to conventional antimicrobial therapy, are also reported in 4.5% of dogs with UTI, with pet regarded as potential reservoirs of drug-resistant uropathogens [1]. The aim of this study was to describe clinical, bacterial culture and urinalysis findings of dogs with suspected UTI, with emphasis on incidence of multi-drug resistant (MDR) infections and factor affecting their occurrence. From 2015 to 2018, 127 urine samples of 79 dogs were retrospectively evaluated. Among dogs (mean age 8.5 ± 3.5 years), 51/79 were males (8 neutered) and 28/79 females (8 sterilized). Mixed breed (6/79), Pinscher (5/79) and German Shepherd (5/79) were the more represented. Urine samples were obtained by cystocentesis (66/127), midstream free flow (56/127) and catheterization (5/127). Positivity on bacterial culture was recorded in 25/127 urine samples (Group A), while 102/127 samples scored negative (Group B), without predisposition of sex (p=0.6) and age (p=0.2). The most frequently bacterial isolates were E. coli (12/25), Staphylococcus spp. (4/25), Pseudomonas spp. (3/25), Enterococcus spp. (2/25), Proteus spp. (2/25) and others (2/25). Lower urinary tract signs (e.g. dysuria, hematuria, pollakiuria) (p=0.02), bacteriuria (p<0.001) and active sediment (p<0.001) were significantly increased in Group A, regardless the collection methods (cystocentesis vs midstream free flow) (p= 0.75). No statistical differences between Group A and B were observed in regards of urine pH (p=0.56), urine specific gravity (p=0.69) and urine protein to creatinine ratio (p= 0.89). An history of antibiotic treatment within 6 weeks before the sampling was recorded in 20/79 dogs and 6/20 had urine positive to urinary culture. Antibiotic-resistance was detected in 20/25 bacterial isolates and, of them, 9/20 were identified as MDR; a significant increase of detection of MDR bacteria was observed in dogs underwent antibiotic therapy (amoxi-clav. and enrofloxacin) within 6 weeks before the sampling (p<0.05). The infections were resolved in 21 dogs, while a chronic cystitis developed in 4 dogs. This study confirms that the presence of bacteriuria, active sediment and clinical signs are associated with UTI in dogs [2], demontrates that the urinalysis is not dependent to the collecting method, and midstream free flow can be an alternative method in dogs. The high prevalence of antibiotic-resistance in dogs with UTI and the increased incidence of MDR in dogs previously treated with antibiotic, confirm the clinical utility of bacterial culture to decrease the prevalence of persistent or recurrent UTIs often difficult to treat using conventional antimicrobial therapy.