Antimicrobial susceptibility of bacteria isolated from urine samples in dogs

Abstract

Urinary tract infections are very common in dogs, while the number of antimicrobials available for therapy has decreased due to the adaptation and evolution of bacterial populations. The aim of the study was to establish the prevalence of the main etiological agents involved in the pathogenesis of urinary tract infections, antimicrobial susceptibility and treatment alternatives.For this study, 50 dogs of different breeds, both females and males, aged between 2 years and 13 years were considered. The experimental part of this study took place between February 2018 and May 2019 in the Department of Microbiology, Faculty of Veterinary Medicine, Cluj-Napoca. Samples were processed using microscopic and cultural examinations. The Petri dishes were inoculated and incubated for 24 hours at 37°C, and interpreted, analyzing the cultural and morphological characteristics of the bacterial colonies as well as the presence or absence of haemolysis areas. The identification of bacterial species was performed by microscopic examination of cells from isolated colonies and biochemical examinations. Antibiotic susceptibility testing was performed by Mueller-Hinton agar disk diffusion technique. The most frequently isolated bacterial strain was E. coli, present in 21 samples of 54 (38.8%), followed by Staphylococcus spp. in 16 (29.6%), Streptococcus spp., present in 10 samples (18.5%), Proteus spp. with 4 samples (7.4%), and Klebsiella spp. and Pseudomonas spp., each present in 3 (5.5%). Bacterial associations were only observed in 7 samples, mainly involving E. coli and Proteus spp., while 4 samples were negative for bacterial growth. Increased susceptibility was observed for enrofloxacin, doxycycline and amoxicillin with clavulanic acid, while increased resistance was recorded for cefovecin, cephalexin and trimethoprim.