Most of the first time simple urinary tract infections usually respond within several days; however, if the symptoms are relapsing or don't resolve, then
a sterile urine culture is performed to look for resistant bacteria, thus allowing a better antibiotic selection, and / or x-rays performed to look for other abnormalities (like urinary tract calculi or stones).
To obtain a
sterile urine sample for
culture, your veterinarian may perform a cystocentesis — using a long,
sterile needle to draw a sample from the bladder through the body wall.