Intravesical instillation of amikacin for treatment of a lower urinary tract infection caused by Pseudomonas aeruginosa in a dog.

Case Description-A 9-year-old neutered male Golden Retriever was evaluated because of recurrent lower urinary tract infection subsequent to placement of a permanent cystostomy tube. Clinical Findings-The dog was clinically normal except for the presence of malodorous urine. Bacteriologic culture of a urine sample obtained by cystocentesis yielded growth of Pseudomonas aeruginosa, which was susceptible to amikacin, gentamicin, imipenemcilastatin, and ticarcillin-clavulanic acid. Treatment and Outcome-The dog was administered amikacin sulfate (15 mg/kg [6.8 mg/lb], SC, q 24 h) for 14 days before treatment was discontinued because of the presence of casts in the urine. The cystostomy tube was replaced, and intravesical instillation of amikacin (15 mg/kg diluted in 30 mL of saline [0.9% NaCl] solution, q 12 h) was initiated. On day 25 of instillation treatment, bacterial culture of a urine sample yielded no growth, urinalysis revealed no casts, and SUN and creatinine concentrations were within reference intervals. On day 27 of instillation treatment, gross hematuria was observed, which resolved following discontinuation of amikacin instillation. Clinical Relevance-In this dog, treatment of a lower urinary tract infection caused by a multidrug-resistant strain of P aeruginosa was successfully achieved with intravesical instillation of amikacin. Results of serial serum biochemical analyses remained within reference limits, and urine casts were not identified on urinalyses during the treatment period, which suggested that systemic absorption of amikacin was minimal. Intravesical instillation of antimicrobials may be a viable treatment option for dogs with lower urinary tract infections caused by multidrug-resistant bacteria.