Adjunctive intravesical EDTA-tromethamine treatment of a biofilm-associated recurrent Escherichia coli cystitis in a dog

Abstract

A 15-month-old spayed female greater Swiss mountain dog was brought to our clinic because of relapsing episodes of urinary tract infection, present since her adoption at 2 mo of age. A diagnosis of chronic bacterial cystitis associated with an invasive, biofilm-forming uropathogenic Escherichia coli was made with bladder-wall histology and fluorescent in situ hybridization analysis. Local treatment with EDTA-tromethamine (EDTA-Tris) infusions along with parenteral cefquinome and prophylactic measures (Type-A proanthocyanidins and probiotics) coincided with clinical and bacterial remission. The dog has been free of clinical signs of urinary tract infection for >4 y. Biofilm-forming uropathogenic E. coli can cause chronic, recurrent cystitis due to low antibiotic efficacy and should be considered in cases of recurrent cystitis in dogs, especially in the absence of identified predisposing factors. This case report describes the diagnostic and therapeutic options that were used to manage a case of this type. Key clinical message: Fluorescent in situ hybridization analysis may be considered in the diagnosis of chronic bacterial cystitis in dogs, and intravesical instillations of EDTA-Tris may be helpful in managing such cases.

FIGURE 1

Light microscopic evaluation of the urinary bladder wall in a female dog. A — The low-magnification image shows an irregular thickening of the mucosa with fibrovascular polyps and several follicular aggregates (*) (hematoxylin and eosin stain; scale bar = 500 μm). B — At high magnification, bacterial rods are observed adherent to the apical surface of urothelial cells (arrows) (hematoxylin and eosin stain; scale bar = 10 μm).

FIGURE 2

Fluorescent in situ hybridization (FISH) analysis of bladder wall biopsies from a female dog. A — Patchy bacterial aggregates adhering to urothelium are visible at low magnification (scale bar = 50 μm). B — Invasive bacterial aggregates are observed in an area of urothelium erosion (scale bar = 25 μm). C — Bacterial aggregates embedded in a polysaccharide-rich matrix close to umbrella cells (scale bar = 25 μm). D — Image suggestive of bacterial aggregates within umbrella cells cytoplasm (scale bar = 25 μm); inset: intracellular bacterial community (scale bar = 5 μm). The FISH analysis stains are as follows: blue, 4′,6-diamidino-2-phenylindole (nuclear stain); green, wheat germ agglutinin (polysaccharide-rich material stain); red, Eub338 universal probe (bacterial stain).