Molecular investigation of Escherichia coli strains associated with apparently persistent urinary tract infection in dogs

Persistent Escherichia coli urinary tract infection (UTI) in dogs is a frustrating clinical problem. Affected dogs often appear to fail to respond to therapy or to reacquire infection shortly after therapy is completed. Urovirulence factors (UVFs) of the infecting E. coli, antibiotic resistance, and tissue colonization may be contributory but have not been evaluated in dogs with persistent E. coli UTI. In this study, the strain types of E. coli in dogs with persistent UTI were evaluated with pulsed-field gel electrophoresis (PFGE) to determine whether persistence was due to acquisition of new isolates or failure to eradicate existing isolates. UVFs in these isolates, assessed by polymerase chain reaction, and antibiograms were correlated with treatment outcome in these dogs. Results documented a mixed pattern: 9 dogs remained chronically infected with 1 or 2 strains, each with distinct reproducible UVFs, but 1 dog was infected with numerous unrelated E. coli strains over time. Two dogs had a mixed pattern, consisting of 1 or more episodes of persistent E. coli infection attributable to a single strain in addition to episodes caused by unrelated strains. Many isolates had no detectable UVFs, highlighting the likely importance of impaired colonization resistance in the affected dogs. Antibiotic resistance was common, often in response to previous treatments, especially with trimethoprim-sulfamethoxazole. Antibiotic resistance patterns differed significantly within PFGE strain types, suggesting lateral acquisition of resistance plasmids or integrons. These results can be used to help guide testing for and management of persistent E. coli UTI in dogs.     

Relationship of upper and lower urinary tract infection and bacterial invasion of uroepithelium to antibody-coated bacteria test results in female dogs

Urinary tract infection was demonstrated in 12 female dogs via bacteriologic culture of a specimen of bladder urine collected by antepubic cystocentesis. Escherichia coli was isolated in pure culture from the urine of 9 dogs. Urine specimens from 2 dogs contained E coli and alpha-streptococci and from 1 dog contained Streptococcus zymogenes in pure culture. In 6 dogs, urinary tract infection was limited to the urinary bladder, whereas 6 dogs had unilateral or bilateral culture-positive renal pelvic urine as well (specimens collected by percutaneous nephropyelostomy). An antibody-coated bacteria (ACB) test was conducted on a portion of the bladder urine specimen from each dog, and the urinary tissues from these 12 dogs and from 6 healthy, noninfected female dogs were examined at necropsy. Tissues were given a subjective score based on the severity of the lesions seen microscopically. Histologic scores, bacterial cultural results, and ACB test results were examined for significance. A significant difference was found in the histologic scores between infected and noninfected dogs (P less than 0.025), but comparisons among histologic scores, cultural results, and ACB test results were not significant among infected dogs. The ACB test could neither be used to localize bacterial infection within the urinary tract nor could it be used to indicate the presence of bacterial invasion of the uroepithelium in dogs.     

Urinary tract infection induced by intermittent urethral catheterization in dogs.

Sterilized and unsterilized catheters were passed into the urinary bladders of 9 clinically normal adult male dogs once daily for 5 consecutive days, and the dogs were examined for up to 30 days to determine whether urinary tract infections developed. Two dogs that were catheterized with clean unsterilized catheters (1 clinically normal dog and 1 dog given immunosuppressant drugs) developed persistent cystitis and pyelonephritis due to infection with Proteus sp. One dog given immunosuppressant drugs developed a mixed bacterial infection (Proteus sp and Escherichia coli) that resolved without treatment between 22 and 30 days later.     

A technique for resection of invasive tumors involving the trigone area of the bladder in dogs: preliminary results in two dogs

Objective— To describe a surgical technique for resection of the entire bladder neck, including the trigone and proximal urethra in dogs with invasive tumors causing life-threatening urinary tract obstruction.
Study Design— Clinical case reports.
Animals— Dogs (n=2) with bladder tumors.
Methods— Circumferential excision of the bladder neck and proximal urethra with preservation of the neurovascular pedicles was performed to remove a rhabdomyosarcoma (dog 1) and a transitional cell carcinoma (dog 2) involving the trigone and bladder neck that were causing urinary tract obstruction. Reconstruction of the bladder and proximal urethra included bilateral ureteroneocystostomy. Adjuvant chemotherapy was administered postoperatively to both dogs.
Results— Postoperatively, dogs 1 and 2 were continent after 7 and 17 days, respectively, and regained normal urinary function after resolution of a transient pollakiuria. Dog 1 had no evidence of local or regional recurrence; however, a large solitary pulmonary metastatic lesion was diagnosed 8 months later. The dog was euthanatized despite a lack of clinical signs. Dog 2 had at least 1 metastatic lesion in the abdominal wall 6 months later and was euthanatized at 580 days because of renal failure.
Conclusion— En-bloc removal of the bladder neck and proximal urethra with preservation of the dorsal vascular and nervous pedicles, although a technically challenging procedure, can be performed without associated urinary incontinence or bladder wall necrosis.
Clinical Relevance— In dogs with invasive bladder tumors causing life-threatening urinary tract obstruction, resection of the bladder neck and proximal urethra should be considered as a promising surgical alternative to urinary diversion.     

TOLERABILITY AND TUMOR RESPONSE OF A NOVEL LOW‐DOSE PALLIATIVE RADIATION THERAPY PROTOCOL IN DOGS WITH TRANSITIONAL CELL CARCINOMA OF THE BLADDER AND URETHRA

Previously reported radiation protocols for transitional cell carcinoma of the canine lower urinary tract have been ineffective or associated with increased side effects. Objectives of this retrospective, cross‐sectional study were to describe safety of and tumor responses for a novel palliative radiation protocol for transitional cell carcinoma in dogs. Included dogs had cytologically or histologically confirmed transitional cell carcinoma of the bladder or urethra, and were treated with 10 once‐daily fractions (Monday–Friday) of 2.7 Gy. Thirteen dogs were sampled, with six treated using radiation as first‐line (induction) therapy and seven treated using radiation as rescue therapy after failing previous chemotherapy. Within 6 weeks of radiation, 7.6% (1/13) dogs had a complete response, 53.8% (7/13) partial response, 38.5% (5/13) stable disease, and none had progressive disease. Three patients presenting with urethral obstruction had spontaneous micturition restored during the treatment protocol. A single patient with unilateral ureteral obstruction was patent at recheck examination. Median survival time from time of initial diagnosis was 179 days. Median survival time from start of radiation was 150 days. Acute radiation side effects occurred in 31% (4/13) patients and were classified as grade 1 or 2. No significant late side radiation side effects were reported. No variables examined were identified as prognostic factors. Findings indicated that the reported radiation protocol was safe in this sample of dogs with bladder and urethral transitional cell carcinoma. Future prospective studies are needed to determine utility of this treatment as a rescue therapy in patients with complete urinary tract obstruction.     

Clinical factors determining the efficacy of urinary bladder tumour treatments in dogs: surgery, chemotherapy or both?

In a study of 44 canine patients suffering from histopathologically proven urinary bladder tumour with a high incidence of transitional cell carcinoma (TCC) (n = 35), a close relationship was found either between the disease-free period and the age (r = -0.40) of animals or between the survival times and the age (r = -0.62) of animals after treatment. In addition to the dog breeds known to be prone to have urinary bladder tumour, we found an additional potentially sensitive breed, the Hungarian Vizsla. The median survival times obtained by the applied treatment types were as follow: 'surgery and chemotherapy' (n = 8/44) 475 days, 'surgery alone' (n = 19/44) 240 days, 'chemotherapy alone' (n = 7/44) 31 days, and 'no treatment' (n = 10/44) 7 days (P < 0.001). According to the findings, chemotherapy combined with surgery completed in time is the most effective protocol in the treatment of urinary bladder tumour cases in dogs. A rational and more effective procedure for the assessment and treatment of urinary bladder tumour cases is presented.     

Proximal Urethral Reconstruction Using a Distally Based Ventral Bladder Tube Flap An Experimental Study

Reconstruction of the proximal urethra using a distally based tube flap mobilized from the ventral bladder wall was performed on 12 clinically normal dogs after total prostatectomy and resection of 2 cm of membranous urethra. One dog was euthanized at 6 hours and one at 36 hours after surgery because of surgical complications. Five dogs were euthanized at 10 days, two dogs at 6 weeks and three dogs at 12 weeks. Advancement of the tube flap allowed for tension-free anastomosis to the membranous urethra. Vascular integrity was maintained in all flaps. Intermittent to continuous postoperative urinary incontinence occurred in 7 of 10 dogs. The incontinence was transient in all 6 and 12 week dogs except one in which a persistent stress incontinence developed. Mild to severe dysuria was noted in 8 of 10 dogs, but was also transient in all of the 6 and 12 week dogs, with the exception of one dog. Postoperative urethral closure pressure profilometry revealed decreased tone in the membranous urethra in all 6 and 12 week dogs. It was concluded that proximal urethral reconstruction, using a ventral bladder tube flap, is a viable technique that may permit functional urodynamic recovery in dogs with significant proximal urethral loss.     

Helicobacter felis infection in dogs: effect on gastric structure and function.

The relationship of Helicobacter felis, an organism that is observed in the stomachs of dogs, to gastric disease in dogs is unclear. The objective of this study was to determine if Helicobacter felis infection alters gastric morphology and gastric secretory function in dogs. Five specific-pathogen-free (SPF), Helicobacter-free Beagle dogs were examined before and for 26 weeks after inoculation with H. felis (ATCC 49179). Three SPF uninfected dogs served as controls. All five dogs became colonized by H. felis as determined by urease activity, histopathology, polymerase chain reaction, and transmission electron microscopic examination of serial gastric biopsies. The degree of colonization ranged from < 1 organism/400 x field to > 10 organisms/400 x field. The fundus, body, and cardia were most heavily colonized. Evaluation of gastric biopsies showed mild gastric inflammation and lymphoid follicles in both infected and uninfected dogs. There was no correlation between the number of organisms observed and the degree of gastric inflammation or number of lymphoid follicles. The gastric secretory axis, assessed by fasting and meal-stimulated plasma gastrin, mucosal gastrin and somatostatin immunoreactivity, fasting gastric pH, and pentagastrin-stimulated gastric acid secretion, was similar in both infected and uninfected dogs. Fasting gastric pH was not a reliable indicator of gastric secretory function. These findings suggest that H. felis may not be a gastric pathogen in dogs. However, the density of colonization and limited duration of infection should be considered when interpreting these findings.     

Comparison of three techniques for the diagnosis of urinary tract infections in dogs with urolithiasis

OBJECTIVES: To identify an appropriate sampling technique(s) to accurately detect the bacteria causing urinary tract infections in dogs with urolithiasis. METHODS: Twenty-one dogs with urolithiasis were included in the study. Three types of samples were taken from each dog. Urine was collected by cystocentesis, and a urinary bladder mucosal biopsy and urolith were retrieved during cystotomy. The samples were then cultured on blood agar and MacConkey's agar to identify the bacteria associated with urinary tract infections. RESULTS: Bacterial urinary tract infection was found in 16 cases (76.19 per cent). The most prevalent bacteria found to cause urinary tract infection were Escherichia coli (n=7), followed by coagulase-positive Staphylococcus species (n=4), Klebsiella pneumoniae (n=2), Pseudomonas aeruginosa (n=2) and Proteus mirabilis (n=1). In the case of a positive urine culture, the same bacteria were also cultured from the urinary bladder mucosal biopsy alone or from both the urinary bladder mucosal biopsy and urolith. However, in the case of a negative urine culture, bacteria were found to be present in the urinary bladder mucosal biopsy or urolith cultures in 23.81 per cent of dogs. The uroliths that gave positive culture results were either infection-induced uroliths composed of struvite and calcium carbonate phosphate, ammonium acid urate only or metabolic uroliths composed of calcium oxalate and calcium phosphate, or calcium phosphate only. All the uroliths that gave negative culture results were metabolic uroliths composed of calcium oxalate and/or calcium phosphate, and uric acid and calcium phosphate. CLINICAL SIGNIFICANCE: When the culture from the urine obtained by cystocentesis is negative, cultures of urinary bladder mucosal biopsy and urolith are recommended in dogs with urolithiasis in order to accurately assess the microbiological status of the urinary tract.     

Phase II Clinical Trial of Carboplatin in Canine Transitional Cell Carcinoma of the Urinary Bladder

Fourteen dogs with histologically-confirmed transitional cell carcinoma (TCC) of the urinary bladder were treated with 300 mg/m² carboplatin every 3 weeks. Response to therapy was assessed with abdominal radiography, double contrast cystography, urinary bladder ultrasonography and thoracic radiography before therapy and at 6–week intervals during therapy. Dogs were monitored for hematologic toxicity with a CBC and platelet count performed immediately before and 10 to 14 days after carboplatin treatment. Tumor responses included progressive disease in 11 dogs and stable disease in 1 dog. Two dogs were euthanized due to carboplatin toxicity before assessment of tumor response. Toxicity included thrombocytopenia with or without neutropenia in 7 dogs and gastrointestinal toxicity in 6 dogs. Carboplatin therapy was not beneficial in the treatment of TCC in the 14 dogs in this study.     

Corticoid production by four dogs with hyperfunctioning adrenocortical tumours during treatment with mitotane (o,p'-DDD).

In two dogs with hyperadrenocorticism due to an adrenocortical tumour, treatment with o,p'-DDD was started. Their hormonal response was monitored by measurements of the urinary corticoid/creatinine ratio. In one dog, two courses of 10 days treatment with o,p'-DDD were ineffective, whereas in the other dog the urinary corticoids decreased to very low levels after only six days of treatment, and corticosteroid supplementation had to be started. Two other dogs received o,p'-DDD according to a protocol used for the treatment of pituitary-dependent hyperadrenocorticism which aims at the complete destruction of the adrenal cortices, with substitution for the induced hyperadrenocorticism. Both dogs made a good recovery and their urinary corticoid/creatinine ratio decreased to within the reference range. In one of them the tumour had decreased considerably in size by five weeks after the start of the treatment.     

Preclinical evaluation of 5-aminolevulinic acid-based photodynamic therapy for canine transitional cell carcinoma

As a prelude to photodynamic therapy, 5‐aminolevulinic acid (ALA) was given orally to healthy dogs. ALA‐induced protoporphyrin IX (PpIX) fluorescence significantly increased in the mucosa of the urinary bladder in an ALA dose‐dependent fashion. Vomiting occurred after ALA administration in 70% of the dogs but did not affect PpIX fluorescence. ALA‐based photodynamic therapy (PDT) of the urinary bladder in healthy dogs caused only submucosal oedema within the bladder wall. No haematologic or serum biochemistry abnormalities were observed after ALA administration. Microscopic haematuria was observed in all the dogs after PDT but was mild and self limiting. ALA‐based PDT was administered to six dogs with transitional cell carcinoma (TCC) of the lower urinary tract. ALA‐based PDT resulted in tumour progression‐free intervals from 4 to 34 weeks in five dogs; one dog with pre‐existing hydronephrosis died shortly after PDT. Dogs with TCC represent an outbred, spontaneous, tumour model for developing PDT protocols for humans with bladder cancer.     

Treatment of cyclophosphamide-induced hemorrhagic cystitis in five dogs

Sterile hemorrhagic cystitis developed in 5 dogs after treatment with cyclophosphamide. Four dogs were being treated with various antineoplastic protocols, and the fifth dog had recurrent immune-mediated thrombocytopenia. In all instances, clinical signs of hematuria and stranguria persisted after cyclophosphamide administration was discontinued. Three dogs required cystotomy to remove necrotic mucosa and calculi. The other 2 dogs were treated with intravesicularly administered dimethyl sulfoxide to decrease inflammation and to inhibit fibroplasia of the bladder wall. In 4 dogs, clinical signs resolved after treatment. The fifth dog, treated surgically, continued to have intermittent urinary incontinence attributable to residual bladder wall fibrosis.     

Fenbendazole for treatment of Paragonimus kellicotti infection in dogs.

The effect of fenbendazole therapy was studied in 9 dogs with pulmonary paragonimiasis induced by inoculation of metacercariae (25/dog) of Paragonimus kellicotti. At 42 to 47 days after 6 dogs were inoculated, they were given fenbendazole in 2 divided doses totaling 50 mg (4 dogs) or 100 mg (2 dogs)/kg of body weight each day for 10 to 14 days. Three dogs were not treated. The passage of Paragonimus eggs in the feces ceased after 3 days at the high dosage and after 3 to 8 days at the low dosage. All dogs were euthanatized and necropsied on day 14. Live flukes were not recovered from the lungs of any treated dog, but 15, 19, and 23 live flukes were recovered from the untreated dogs.     

Staphylococcal colonization of mucosal and lesional skin sites in atopic and healthy dogs

Staphylococcal colonization was compared in healthy dogs and in dogs with atopic dermatitis. Bacterial swabs were collected from the nasal mucosa, ear and perineum of 43 healthy and 24 atopic dogs and also from potentially infected skin lesions of the atopic dogs. Coagulase positive staphylococcal isolates were identified to the species level. At the time of this study Staphylococcus intermedius was considered a single species but has since been recognized as comprising at least three species with canine isolates believed to belong to Staphylococcus pseudintermedius . Of atopic dogs, 87.5% were colonized with S. intermedius compared to only 37.2% of healthy dogs. The ear was the only carriage site that showed any significant difference in S. intermedius isolation between healthy and atopic dogs. The perineum represented the most frequently colonized mucosal site for both groups. Sampling the nasal mucosa alone identified 71.4% of atopic and 37.5% of healthy S. intermedius carriers. Inclusion of a perineal swab identified 100% of atopic and 93.8% of healthy carriers. S. intermedius was isolated from all the lesional sites sampled from atopic dogs. Significantly fewer dogs were colonized by Staphylococcus aureus than S. intermedius , and there was no significant difference between S. aureus colonization of atopic and healthy dogs. S. aureus was not recovered from any lesions in atopic dogs. The results show that S. intermedius carriage is more prevalent in atopic dogs compared to healthy dogs and that to identify staphylococcal carriers both the nasal mucosa and the perineum should be sampled.     

URINARY BLADDER MURAL HEMORRHAGE ASSOCIATED WITH SYSTEMIC BLEEDING DISORDERS IN THREE DOGS

The sonographic appearance of three dogs with diffuse bladder wall thickening due to mural hemorrhage is described. Two dogs were diagnosed with immune-mediated thrombocytopenia and the third dog with vitamin K antagonist toxicity. Urinary bladder wall thickening ranged from 5 to 12 mm on initial sonographic examination. In the two surviving dogs, the bladder wall returned to normal thickness. One dog, euthanatized for refractory hematuria, had submucosal hemorrhage in the urinary bladder at necropsy. Urinary wall thickening sonographically resolved at a rate of approximately 1 mm per day. Mural hemorrhage should be considered in patients with concurrent bleeding disorder and urinary bladder wall thickening.     

Evaluation of a method using Proteus mirabilis and Pseudomonas aeruginosa to experimentally induce dual infection of the urinary bladder in dogs

OBJECTIVE: To evaluate a method using Proteus mirabilis and Pseudomonas aeruginosa to experimentally induce dual infection of the urinary bladder in dogs. ANIMALS: 6 healthy mixed-breed dogs. PROCEDURE: Dogs were anesthetized, and cystitis was induced by infusing a solution of salicylic acid in ethanol into the bladder, followed by an inoculum containing field isolates of P. mirabilis and P. aeruginosa. Dogs were examined daily for 21 days after induction of cystitis. On day 21, dogs were euthanatized, and urinary bladder, renal pelvis, and prostate specimens were submitted for bacterial culture. RESULTS: After induction of cystitis, all dogs had evidence of thickening of the bladder wall, dysuria, tenesmus, and hematuria. Urinalysis revealed proteinuria, hematuria, and pyuria. All urine samples obtained on day 21 yielded growth of P. mirabilis, but P. aeruginosa was not cultured from any of these samples. Proteus mirabilis was isolated from bladder, renal pelvis, or prostate specimens from 4 dogs; P. aeruginosa was not isolated from any of the tissue specimens. CONCLUSION: Results suggest that the method used in the present study fails to induce dual infection of the urinary bladder with P. mirabilis and P. aeruginosa. The inability to establish a persistent dual infection with this method may have been a result of insufficient pathogenicity of the Pseudomonas isolate or an inadequacy of the experimental design.     

Haemangiosarcoma of the urinary bladder in a dog

Haemangiosarcoma of the urinary bladder is reported in a dog. The bladder mass was detected incidentally during physical examination. Partial cystectomy with unilateral ureteroneocystostomy were performed to remove the tumour en bloc. Necrosis of the urinary bladder was diagnosed 10 days postoperatively and the dog was euthanased.     

Reduction of hydronephrosis and hydroureter associated with ectopic ureters in two dogs after ureterovesical anastomosis

Severe hydronephrosis and hydroureter associated with ectopic ureters were diagnosed in 2 dogs. Surgical transplantation of the ectopic ureters into the urinary bladder resulted in urinary continence in both dogs. Intravenous urography revealed a marked decrease in the size of hydronephrosis and hydroureter in both dogs 28 to 35 weeks after surgery. In 1 dog with bilateral ureteral ectopia, kidney size and renal function remained normal for 5 years after surgery. A dog with one ectopic ureter and an associated ureterocele had a marked reduction in size of the affected kidney and an apparent decrease in function of that kidney, as indicated by decreased opacification on an intravenous urogram.     

Cisplatin (cisdiamminedichloroplatinum) for Treatment of Transitional Cell Carcinoma of the Urinary Bladder or Urethra

The records of 15 sequential cases of transitional cell carcinoma of the urinary bladder or urethra in dogs were examined to determine the results of treatment with cisplatin (cisdiamminedichloroplatinum) and to record and assess toxicities. All dogs had measurable disease and were considered eligible for evaluation of toxicity following one cisplatin treatment. Three dogs were eliminated from evaluation of efficacy because of acute toxicities. Of the 12 remaining dogs that received two or more cisplatin treatments, evaluations at the end of the second month of treatment revealed no complete responses; however, three dogs showed partial responses and six dogs maintained stable disease. Three dogs had tumor progression. The median survival time for these 12 dogs was 180 days (mean, 220 days; range, 36 to 589 days). Three dogs were azotemic before treatment. Two of these dogs showed improvement in renal function following therapy. Six of the other twelve dogs developed increases in serum creatinine during therapy. The objective and subjective improvements of some dogs to cisplatin chemotherapy suggest that this agent is active in selected dogs with transitional cell carcinomas of the urinary tract.