Urinary tract infection (UTI) in dogs and cats: etiology and antimicrobial resistance

Bacterial urinary tract infections (UTIs) are a common cause of disease in dogs, cats and humans. Although Gram-positive bacteria such as Staphylococcus spp., Streptococcus spp. and Enterococcus spp. are linked with UTIs, Gram-negative bacteria (Escherichia coli, Proteus spp., Klebsiella spp., Pseudomonas spp. and Enterobacter spp.) account for 75% of the cases. This study aimed to determine the frequency of different genera of bacteria in UTIs of dogs and cats as well as their susceptibility to antimicrobials used in clinical routine. Therefore, urine samples from 100 dogs and cats suspected of UTI were collected aseptically. Samples underwent to microbiological evaluation through qualitative and quantitative methods, and urinalysis. All isolates were tested for antimicrobial susceptibility. UTI was confirmed in 74% of animals, with no predominance in one gender. With regard to age, 85% of dogs and 87% of cats were older than six years. Ninety-five bacterial strains were isolated with higher frequency of Escherichia coli (55% of total) of serogroups O6 and O2. High levels of antimicrobial resistance were found. Gram-positive strains had the highest resistance to tetracycline (46.1%), enrofloxacin, cotrimazol and streptomycin (42.3% each), while above 50% of Gram-negative were resistant to amoxicillin and tetracycline. Multidrug resistance has been observed in more than 50% of the major genera isolated. Considering the zoonotic potential of E. coli strains and its strong participation in antimicrobial resistance dissemination, the important role of the veterinarians in the prevention and control of animal UTIs and their contribution to public health must be emphasized.