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International Society for Companion Animal Infectious Diseases (ISCAID) guidelines for the diagnosis and management of bacterial urinary tract infections in dogs and cats

Weese JS, Blondeau J, Boothe D, Guardabassi LG, Gumley N, Papich M, Jessen LR, Lappin M, Rankin S, Westropp JL, Sykes J. International Society for Companion Animal Infectious Diseases (ISCAID) guidelines for the diagnosis and management of bacterial urinary tract infections in dogs and cats. Vet J. 2019 May;247:8-25. doi: 10.1016/j.tvjl.2019.02.008. Epub 2019 Feb 26. PubMed PMID: 30971357

While this blog usually focuses on new research in feline medicine, it is equally if not more important to take the time to review the state of veterinary medicine and discuss current standards of care. Consensus statements are recommendations made by panels of experts based on the best quality evidence in the literature. The International Society for Companion Animal Infectious Disease (ISCAID) has previously published consensus guidelines for the treatment of several classes of infection, and has recently updated their statement on the treatment of urinary tract infections. While the article focuses on dogs and cats, this blog will focus on the feline portion.

The statement classifies urinary tract infections into several categories based on history, clinical signs, and concurrent disease. These categories include:

  • Sporadic Bacterial Cystitis (Simple Uncomplicated UTI)- Healthy, non-pregnant females or neutered males without urinary tract abnormalities or relevant co-morbidities with less than 3 episodes of bacterial cystitis in the last 12 months. Animals must have clinical signs of lower urinary disease (ie pain, straining, inappropriate urination, etc), as well as a positive urine culture. As primary UTI is rare in cats, this should not be diagnosed without a positive culture.
  • Recurrent Bacterial Cystitis- Three or more episodes of bacterial cystitis in a 12 month period or two episodes in 6 months. Generally associated either with an underlying cause (stones, anatomical abnormalities, systemic disease, etc) or inappropriate treatment of a previous UTI.
  • Upper Urinary Tract Infection (Pyelonephritis)- Infection of the kidney tissue either through ascending infection or bloodborne infection. Combination of positive urine culture and signs of renal pain, azotemia, lethargy, fever, casts, pelvic dilation, and other clinical and laboratory signs.
  • Bacterial Prostatitis- This is extremely uncommon in cats and is not really discussed in this species
  • Subclinical Bacteriuria- A positive urine culture with no clinical signs of lower urinary disease. Blood and white blood cells may be present, but the animal has no signs of lower urinary disease, or signs attributable to a concurrent condition (ie increased urination may be due to diabetes and not bladder infection)
  • Urinary catheters- Any patients with indwelling or temporary urinary catheters
  • Urologic surgery and implants- Patients undergoing cystotomy, scoping, stent or SUB placement, or other urologic procedures
  • Medical dissolution of uroliths- Cats with struvite stones rarely have underlying infections, but if urine culture is positive, therapy may be indicated as for sporadic cystitis.

Based on each of these categories, the panel made recommendations on the diagnostic path, treatment, and monitoring of animals with these conditions. While a full discussion of event he feline-relevant sections of this consensus statement would be beyond the scope of this blog, a few important points can be taken away. These include:

  • Don’t treat a UTI unless there are clinical signs- Subclinical bacteriuria should not be treated unless there is significant clinical risk for progression. Even in diabetic, cushingoid, or post-UTI treatment populations, the presence of bacteria or pyuria is not enough to justify therapy.
  • In cats, treatment should always be based on culture and sensitivity (C&S)
  • Samples should be collected by cystocentesis unless there are direct contraindications
  • NSAIDs or other pain control may be as effective as antibiotics and may be used in place of empirical therapy while awaiting culture results
  • Amoxicillin is the most reasonable empirical antibiotic choice. Amoxicillin with clavulanic acid is acceptable but rarely needed. TMS is another acceptable empirical choice. Other drugs should be based on culture results or significant clinical judgement
  • Duration of therapy should be 3-5 days
  • Post-treatment culture is not recommended for sporadic cystitis, and is of debatable utility for recurrent cystitis
  • Empirical therapy of pyelonephritis should involve a fluoroquinolone, cefotaxime or ceftazidime, or another broad spectrum antimicrobial with efficacy against Enterobacteriaceae. 10-14 days of treatment is recommended.
  • Urinary catheters should be placed and cared for aseptically and remain in place as short a time as possible. Prophylactic antimicrobials, culture of the catheter tip, and routine culture should be discouraged.
  • Cats rarely have infection-associated struvite uroliths, and so antibiotic therapy is rarely indicated. Bacterial infection alongside struvite may be subclinical.

A major limitation to these recommendations is the determination of whether clinical signs are present. While some cats present with typical hematuria, stranguria, and inappropriate urination, other animals with more mild signs and stoic demeanors may show limited indications of disease. This limits the ability of veterinarians to differentiate subclinical bacteriuria from bacterial cystitis. This is not a purely veterinary concern; a similar issue is encountered by physicians working with senile or non-verbal patients, many of whom may be predisposed to lower urinary infections.

Taken together, the recommendations from this guideline detail a plan for more responsible, targeted, and effective antimicrobial use in lower urinary disease. There is a general trend towards shorter courses of therapy, basing therapy on culture and sensitivity results, treating only the animals that need treatment, and using antimicrobials of least concern as first line choices.  While there may be practical and financial difficulties associated with following these recommendations in some situations, striving to practice according to the consensus described will help provide the best medicine to individual patients and minimize antimicrobial resistance in the future.

See Also

Weese, J.S., Blondeau, J., Boothe, D., Breitschwerdt, E., Guardabassi, L., Hillier, A., Lloyd, D., Papich, M.G., Rankin, S., Turnidge, J.D., et al., 2011. Antimicrobial use guidelines for treatment of urinary tract infections in dogs and cats: antimicrobial guidlines working group of the International Society for Companion Animal Infectious Diseases. Vet. Med. Int. 4, 1–9.

Lulich, J.P., Berent, A.C., Adams, L.G., Westropp, J.L., Bartges, J.W., Osborne, C.A., 2016. ACVIM small animal consensus recommendations on the treatment and prevention of uroliths in dogs and cats. J. Vet. Intern. Med. 30, 1564–1574