Diagnosis and Management of Canine Sporadic Cystitis in Primary Veterinary Practice

Dogs with clinical signs of lower urinary tract disease are commonly encountered in veterinary practice, and UTI is a common indication for antibiotic prescription. Clinical signs of lower urinary tract disease are characteristic, but unspecific for infection and the prevalence of cystitis in dogs with compatible clinical signs is reportedly around 50%.^1,2 Only dogs with bacterial infection (cystitis) will benefit from antimicrobial treatment and rational clinical decision-making is therefore a prerequisite to ensure proper case management and prudent use of antibiotics.

Clinical decision-making can be divided in two phases: (i) The decision to treat with an antimicrobial and the (ii) choice of antimicrobial class (drug-dose­ duration).

Diagnosis

Several studies have investigated the sensitivity and specificity of available point-of-care diagnostic tests (Table 1) for identification of clinically relevant bacterial growth (significant bacteriuria). The studies were performed in tertiary facilities or university settings, and results are therefore not necessarily representative of the accuracy obtained in veterinary primary practice.

Table 1. Accuracy of currently available point-of­ care diagnostic tests

Quantitative bacterial culture (QBC) is still the gold standard for diagnosing UTI, although new and faster methods to discriminate cases with and without infection are emerging.³ When performed by trained personnel, microscopy of stained sediment can be a useful point-of-care test and is recommended along with bacterial culture to diagnose sporadic cystitis in dogs.^4,5 Complete urinalysis is part of the standard diagnostic work up and can provide information with regard to underlying or concomitant disease processes.

The purpose of susceptibility testing is dual: to target choice of treatment to the individual patient and to monitor susceptibility trends in practice. In areas of low resistance to first line agents, susceptibility testing of bacteria from first episodes of canine sporadic cystitis may be redundant; however, regular susceptibility testing of primary cases are necessary for surveillance at practice level. In-house susceptibility testing is generally not adequate for surveillance purposes or for diagnostic work-up of recurrent cystitis or upper UTI. When applied for sporadic cystitis one must ensure use of validated point of care tests only, and performance of regular quality control. Susceptibility testing can easily be performed following in-house culture by sending swabs of colonies, or the entire agar plate, to a specialized laboratory.

Timing of Treatment

Appropriate clinical decision making is not only dependent on accurate diagnostic tools, it also depends on timing. A recent prospective study in Denmark showed that 88% of dogs with clinical signs of UTI were diagnosed with UTI according to the veterinarians, although only 49% of the dogs had significant bacteriuria on the gold standard QBC.² As a consequence there was a high proportion of antibiotic over-prescription in dogs with suspected UTI. This resulted not only from lower accuracy of diagnostic tests when applied in practice, but mainly from a disconnection between test results and clinical decision making. In particular for bacterial culture, the decision to treat was made prior to reading of the test result. Preliminary results from an ongoing randomized controlled diagnostic study suggest that use of point of care culture promotes appropriate antibiotic use if treatment is withheld for one day until test results are available.

Management of Sporadic Cystitis

Antimicrobial treatment of sporadic cyst itis first of all aims at solving the clinical signs, more than completely eradicating the bacteriuria.

To avoid inappropriate overtreatment a “test - read - treat” strategy should be applied whenever possible. Withholding empiric antimicrobial treatment for 24 hours while awaiting the result of point of care culture is an option to consider in many cases of canine sporadic cystitis. Palliative treatment with non-steroidal anti­inflammatory drugs (NSAIDS) can be initiated, where no contraindications are present.

Choice of antibiotic treatment should ideally be based on susceptibility data. This is however rarely rapidly available, and initiation of empiric treatment of non­recurrent cases is justified if significant bacteriuria is found on in-house QBC. Amoxicillin and potentiated sulfonamides (TMS) are both accumulating in high concentrations in urine and are therefore generally good first line agents towards the most common uropathogens. Resistance-rates do however vary across Europe,⁶ and (when available) local/regional guidelines should be consulted to guide empiric choice of antibiotic class.

There is very sparse evidence with regard to optimal duration of treatment in companion animal UTI including canine sporadic cystitis.⁷ Recent randomized controlled studies suggest that short term (3 days) treatment of TMS⁸ and high dose enrofloxacin⁹ is non-inferior to long term (7–14 days) treatment with beta lactams in treating canine sporadic cystitis. Short-term treatment with amoxicillin has not been investigated in dogs, but in people a 3–5 days course of pivmecillinam is considered adequate.¹⁰ The benefits of short-term treatment include not only reduced antimicrobial resistance selection pressure, but also reduced adverse effects, increased compliance and reduced costs.

Monitoring of bacteriuria during or after completion of therapy is not advised unless clinical signs persist or recur.

References

1.  Serensen TM, Jensen AB, Damborg P, Bjernvad CR, Guardabassi L, Jessen LR. Evaluation of different sampling methods and criteria for diagnosing canine urinary tract infection by quantitative bacterial culture. Vet J. 2016;216:168–173.

2.  Soerensen TM, Bjornvad CR, Hoelmkjaer KM, Guardabassi L, Bjerrum L, Jessen LR. Research Communications of the 26th ECVIM-CA Congress. Diagnostic work-up does not affect appropriate antibiotic prescription in dogs with suspected urinary tract infection - an observational study in Danish small animal practices. J Vet Intern Med. 2017;31(1):217.

3.  Jacob ME, Crowell MD, Fauls MB, Griffith EH, Ferris KK. Diagnostic accuracy of a rapid immunoassay for point of-care detection of urinary tract infection in dogs. Am J Vet Res. 2016;77(2):162–166.

4.  Swenson CL, Boisvert AM, Gibbons-Burgener SN, Kruger JM. Evaluation of modified Wright-staining of dried urinary sediment as a method for accurate detection of bacteriuria in cats. Vet Clin Pathol. American Society for Veterinary Clinical Pathology. 2011;40(2):256–264.

5.  Swenson CL, Boisvert AM, Kruger JM, Gibbons-Burgener SN. Evaluation of modified Wright-staining of urine sediment as a method for accurate detection of bacteruria in dogs. J Am Vet Med Assoc. 2004;224(8):1282–1289.

6.  Marques C, Gama LT, Belas A, Bergstrom K, Beurlet S, Briend-Marchal A, et al. European multicenter study on antimicrobial resistance in bacteria isolated from companion animal urinary tract infections. BMC Vet Res. 2016;12(1):213.

7.  Jessen LR, Sorensen TM, Bjornvad CR, Nielsen SS, Guardabassi L. Effect of antibiotic treatment in canine and feline urinary tract infections: a systematic review. Vet J. (London, England: 1997). 2015;203(3):270–277.

8.  Clare S, Hartmann FA, Jooss M, Bachar E, Wong YY, Trepanier LA, et al. Short - and long-term cure rates of short-duration trimethoprim-sulfamethoxazole treatment in female dogs with uncomplicated bacterial cystitis. J Vet Int Med. American College of Veterinary Internal Medicine. 2014;28(3):818–826.

9.  WestroppJL, Sykes JE, from S, Daniels JB, Smith A, Keil D, et al. Evaluation of the efficacy and safety of high-dose short duration enrofloxacin treatment regimen for uncomplicated urinary tract infections in dogs. J Vet Int Med. American College of Veterinary Internal Medicine. 2012;26(3):506–512.

10.  Grabe M, Bartoletti R, Bjerklund-Johansen TE, Cek HM, Pickad RS, Tenke P, et al. Guidelines on Urological Infections. EAU, European Association of Urology; 2014.