Leading Off: New guidance for treating bacterial UTIs

Veterinarians are often presented with patients that have signs of lower urinary tract disease characterized by hematuria, pollakiuria, dysuria, and inappropriate urination. Many of these patients are given antimicrobial agents for presumed bacterial urinary tract infection (UTI).

Joseph W. Bartges

Bacterial UTI occurs in 10% to 15% of dogs in their lifetimes1; however, the prevalence of bacterial UTI in cats is variable. In cats less than 10 years of age, it occurs in 1% or less, while in cats older than 10 years, it may occur in > 50% of cases with lower urinary tract signs.1

Microscopic examination of an unstained urine sediment has only a 40% positive predictive value and a 95% negative predictive value,2 so patients may receive antimicrobial agents for presumed bacterial UTI based on this information when it is erroneous. Additionally, the most common cause of lower urinary tract signs in cats less than 10 years of age is idiopathic cystitis, affecting 55% to 65% of these patients, which typically resolves in less than seven days of onset.1 If such a patient is given an antimicrobial agent for presumed bacterial UTI and the clinical signs resolve within seven days, then an erroneous diagnosis of bacterial UTI has likely been made—and the cat more likely had idiopathic cystitis.

Because urinary tract disease is common in dogs and cats and accounts for frequent use (and presumably improper use) of antimicrobials, guidelines for diagnosing and managing urinary tract infections have been developed. Veterinary Medicine International has published "Antimicrobial use guidelines for treatment of urinary tract disease in dogs and cats."3 These guidelines were created by the Antimicrobial Guidelines Working Group of the International Society for Companion Animal Infectious Diseases.

The guidelines provide recommendations for the diagnosis and antimicrobial treatment of simple and complicated bacterial UTI, including management of patients with indwelling urinary catheters, asymptomatic bacterial UTI, pyelonephritis, and UTI with multidrug-resistant bacterial organisms. Recommended dosages for antimicrobial agents are also presented. The recommendations are based on available data when present along with expert opinion considering the principles of infectious diseases, antimicrobial therapy, antimicrobial resistance, pharmacology, and internal medicine.

These guidelines provide an important framework for using antimicrobial agents and for managing patients with bacterial UTI in companion-animal practice. Visit http://hindawi.com/journals/vmi/2011/263768 to read the guidelines. (Also see "Hot Literature: Antibiotic guidelines for dogs and cats with urinary tract disease.")

Joseph W. Bartges, DVM, PhD, DACVIM, DACVN, Department of Small Animal Clinical Sciences, College of Veterinary Medicine, The University of Tennessee, Knoxville, TN 37996.

REFERENCES

1. Pressler B, Bartges JW. Urinary tract infection. In: Ettinger SJ, Feldman EC, eds. Textbook of Small Animal Internal Medicine. 7th ed. St. Louis, Mo: Elsevier Saunders, 2010;2036-2047.

2. Swenson CL, Boisvert AM, Kruger JM, et al. Evaluation of modified Wright-staining of urine sediment as a method for accurate detection of bacteriuria in dogs. J Am Vet Med Assoc 2004;224(8):1282-1289.

3. Weese JS, Blondeau JM, Boothe D, et al. Antimicrobial use guidelines for treatment of urinary tract disease in dogs and cats: Antimicrobial Guidelines Working Group of the International Society for Companion Animal Infectious Diseases. Vet Med Int 2011;2011;263768. Epub 2011 Jun 27.