Bacterial infections of the lower urinary tract may or may not cause clinical signs, and signs may be similar to those of other diseases of the lower urinary tract. This comprehensive survey covers all the bases from diagnosis to treatment and prevention and includes specifics for the physical examination, tests, treatment, and prevention of bacterial urinary tract infections (UTI). Complete urinalysis of a sample collected by cystocentesis is the best way to screen for suspected UTI. A urine culture is definitive, and a urine sediment examination should always be performed to rule out other causes of lower urinary tract disease. Abdominal radiography and ultrasonography for evaluating the kidneys and bladder can reveal uroliths, renomegaly, or other defects that may predispose to UTIs. Endoscopy of the lower urinary tract can be useful in identifying lesions. Bacteria that commonly cause UTIs are the same in dogs and cats, with Escherichia coli, the most common, accounting for 1 of 3 to 1 of 2 of all organisms isolated from infected animals. The second major group of organisms is gram-positive staphylococci and streptococci, accounting for another 1 of 4 to 1 of 3 of isolates recovered. Less commonly seen are species of Proteus, Klebsiella, Pasteurella, Enterobacter, Pseudomonas, Corynebacterium, and Mycoplasma. Successful treatment of bacterial UTI is dependent on whether the infection is an uncomplicated temporary breech in bodily defenses (no underlying structural, functional, or neurologic abnormality) or whether it is complicated by a predisposing factor, such as renal failure, hyperadrenocorticism, or diabetes. Eradication is dependent on selection of the appropriate antibiotic administered at the proper dosage and duration with appropriate follow-up, especially in the case of relapse, reinfection, or superinfection. Prevention is effected by minimizing conditions that impair host defenses, such as prolonged catheterization, endoscopy, and perineal urethrostomies (the magnitude of the risk increases with preexisting urinary tract abnormality). Prophylactic antimicrobial therapy may be indicated in animals with relapses or frequent infections.

COMMENTARY: This article details the scientific underpinnings of contemporary management of UTI in dogs and cats. Most important is the understanding that UTI often represents temporary or chronic loss of normal host defense mechanisms and appropriate management requires these changes to be identified and addressed.

Bad bugs: bacterial UTI. Bartges J. NAVC PROC, January 2004, p571.