Effect of therapy on susceptibility to urinary tract infection in male cats with indwelling urethral catheters

A clinical approach to multidrug-resistant urinary tract infection and subclinical bacteriuria in dogs and cats

Multidrug-resistant bacteria are increasingly isolated from the urinary tract of pets, particularly those that suffer from concurrent conditions, have been hospitalised, or were treated with antimicrobials in the recent past. Many of the multidrug-resistant bacteria encountered are resistant to all commonly used oral antibiotics. This poses both a therapeutic dilemma in the individual pet and a threat to public health. This article begins with an overview of multidrug resistance in organisms that are commonly isolated from the urinary tract of pets. This is followed by a proposed clinical approach to managing multidrug-resistant urinary bacteria, which summarises current knowledge regarding appropriate sampling and analysis, reviews the current guidelines regarding appropriate antimicrobial use and discusses treatment options that might be considered. The article highlights several shortcomings of the current knowledge to be considered when planning future clinical research and developing policies.

Effect of intraoperative positioning on postoperative neurological status in cats after perineal urethrostomy

OBJECTIVES

The aim of this study was to evaluate and quantify the changes in neurological status in cats after perineal urethrostomy performed in dorsal and ventral recumbency.

METHODS

This was a prospective, randomised study. Twenty male castrated cats with feline lower urinary tract disease presented for perineal urethrostomy were enrolled in this study. Surgery was performed in either dorsal recumbency (group A) or ventral recumbency (group B). Motor response of patellar tendon, gastrocnemius muscle, pelvic limb withdrawal and perineal reflexes, as well as the presence of spinal pain in the lumbosacral region, motor function of the tail and faecal continence, were examined before surgery, and 24 h and 14 days after surgery.

RESULTS

The animals had a mean weight of 5.07 ± 1.08 kg, with a mean age of 6.12 ± 1.85 years. Weight and age were not significantly different between groups A and B (both P = 0.897). All tested parameters of the neurological examination performed prior to surgery were considered normal in both groups (P = 1). The comparison between neurological examinations (perineal reflex and spinal pain) before and 24 h after surgery revealed a significantly decreased briskness of the perineal reflex and an increased occurrence of spinal pain 24 h after surgery (P = 0.043 and P = 0.031, respectively). However, the changes of aforementioned parameters were statistically insignificant (P = 0.249 and P = 0.141) between groups A and B. The other parameters (patellar tendon, pelvic limb withdrawal and gastrocnemius muscle reflexes, motor function of the tail and faecal continence) were statistically insignificant (P = 1) before surgery and 24 h after surgery, as well as between groups A and B 24 h after surgery. Results of all tested parameters were statistically insignificant (P = 1) before surgery and 14 days after surgery, as well as between groups A and B 14 days after surgery.

CONCLUSIONS AND RELEVANCE

The briskness of the perineal reflex was significantly decreased and the occurrence of spinal pain significantly increased 24 h after surgery. A parallel with a low-grade positioning-dependent nerve injury as described in human medicine may be drawn. However, no positioning method was proven to be superior to the other.

Incidence of bacteriuria at presentation and resulting from urinary catheterization in feline urethral obstruction

OBJECTIVE

To determine the incidence of bacteriuria at the time of presentation and as a result of indwelling urethral catheterization in naturally occurring feline urethral obstruction (UO).

DESIGN

Prospective observational study.

SETTING

University teaching hospital.

ANIMALS

A population of 34 male cats with UO admitted for standard medical care.

INTERVENTIONS

A presenting urine sample was obtained by cystocentesis (precatheterization). After catheterization (performed under strict aseptic technique), a urine sample was obtained through the urinary catheter every 24 hours, as well as just prior to catheter removal. Urine was applied to culture media within 30 minutes of collection or refrigerated immediately at 4°C for subsequent culture the following morning. Samples positive for growth (defined as > 10⁴ colony forming units/mL) had bacterial identification and susceptibility testing performed.

MEASUREMENTS AND MAIN RESULTS

All 34 cats enrolled had initial culture performed. Of these, 1 patient died and 2 were euthanized within 24 hours and therefore subsequent cultures were obtained. The remaining 31 cats had median catheterization time of 42 hours (range 20-110 hours). No urine cultures yielded growth at presentation (0/34). A total of 4 of 31 patients (13%) subsequently had bacterial cultures that yielded growth. In these cases, all yielded growth by the 24-hour time point, and all had the same organism identified on subsequent cultures. Identified bacteria included Streptococcus spp. (3) and Pasteurella spp. (1).

CONCLUSIONS

The male cats with UO in this study did not have bacteriuria at the time of presentation. The overall incidence of acquired bacteriuria was found to be 13% and could represent a transient bacterial population or true bacterial urinary tract infection. Based on these findings, empirical administration of antibiotics is not warranted in male cats with UO.

Controversies in the management of feline urethral obstruction

OBJECTIVE

To discuss areas of differing opinion in the management of feline urethral obstruction and present current evidence to either support or refute common practices.

ETIOLOGY

Urethral obstruction may occur as a result from a functional obstruction (idiopathic obstruction) or a physical obstruction, such as mucous plugs or calculi within the urethra. Potential risk factors for obstruction in cats include predominantly indoor status, decreased water intake, and increased body weight.

DIAGNOSIS

The diagnosis is most commonly made based on history and initial physical exam-straining to urinate, vocalizing, signs of systemic illness, moderate to large firm bladder on abdominal palpation.

THERAPY

Treatment is based on available evidence. The type of IV isotonic crystalloid used does not seem to matter and rate should be determined by need for fluid resuscitation, and replacement of deficit and ongoing losses. Though controversial, cystocentesis appears to be safe and may offer some benefits in initial management. There is evidence to suggest a smaller urethral catheter (3.5 Fr) may be associated with decreased risk of reobstruction. Routine use of antimicrobial agents in hospital is not recommended; they should be dispensed based on culture performed at the time of catheter removal. Though commonly used, evidence in support of antispasmodics is limited and further prospective investigation is needed.

PROGNOSIS

Feline urethral obstruction is associated with 90-95% survival, with reported recurrence rates of 15-40%. Potential factors affecting recurrence include size or duration of indwelling urinary catheter, use of antispasmodic agents, patient age, and indoor-outdoor lifestyle; however, different studies offer conflicting results. Increased water intake and environmental modification do seem to decrease risk of recurrence.

A retrospective analysis of urethral rupture in 63 cats

The aim of this study was to investigate the short- and long-term morbidity and mortality associated with urethral rupture in cats. Medical records were reviewed from four veterinary hospitals. Diagnosis was made from retrograde urethrography or direct visualisation during surgery. Location of rupture was categorised as pre-, intra- or post-pelvic. Follow-up data were collected from referring veterinarians. Sixty-three cats were included in the study of which, males predominated (88.9%). Trauma was the most common cause (n = 35; 55.6%) with the remainder due to iatrogenic injury. Forty-eight cats (88.9%) were treated surgically and six (11.1%) managed conservatively. Significant differences between cats suffering traumatic versus iatrogenic injury included the presence of musculoskeletal injuries (P <0.001); the location of rupture (P <0.001); the degree of rupture (P <0.001); definitive management (P <0.001) and short-term complications (P = 0.026). Short-term complications were significantly associated with the following: musculoskeletal injuries (P = 0.012); uroabdomen/uroretroperitoneum (P = 0.004); azotaemia (P = 0.021); postoperative urinary diversion (P = 0.036) and >1 surgery performed (P = 0.006). Forty-seven cats (74.6%) survived to discharge. Prognostic factors associated with survival to discharge included the presence of musculoskeletal injuries (P = 0.017); cause of rupture (P = 0.017); location of rupture (P = 0.039) and definitive management (P = 0.020). Twenty-four cats (57.1%) suffered short-term complications and 10 (27.0%) suffered long-term complications. Of those cats surviving to discharge 30 (71.4%) had a good outcome. Median follow-up was 16 months. Outcome was significantly associated with cause of rupture (P = 0.04); short-term complications (P = 0.03) and long-term complications (P <0.001). In conclusion, a significantly greater proportion of cats with iatrogenic injuries survived to discharge and had a good outcome compared with those that suffered trauma.

Clinical features and risk factors for development of urinary tract infections in cats

The clinical and diagnostic features of 155 cats with urinary tract infection (UTI) and 186 controls with negative urine culture/s were characterized retrospectively (signalment, clinical signs, urinalysis, urine culture, concurrent diseases, lower urinary tract diagnostic/therapeutic procedures). Multivariable logistic regression was used to identify risk factors associated with UTI. Cats of all ages were affected by UTI with no sex/breed predisposition. Lower urinary tract signs were absent in 35.5% of cats with UTI. Pyuria and bacteriuria had sensitivities of 52.9% and 72.9%, and specificities of 85.5% and 67.7% for detection of UTI, respectively. Risk factors significantly associated with increased odds of UTI were urinary incontinence [odds ratio (OR)=10.78, P=0.0331], transurethral procedures (OR=8.37, P<0.0001), urogenital surgery (OR=6.03, P=0.0385), gastrointestinal disease (OR=2.62, P=0.0331), decreased body weight (OR=0.81, P=0.0259) and decreased urine specific gravity (OR=0.78, P=0.0055). Whilst not independently significant, renal disease and lower urinary tract anatomic abnormalities improved statistical model performance and contributed to UTI.

Vaginourethroplasty as a salvage procedure for management of traumatic urethral rupture in a cat

This report describes a cat that suffered pelvic urethral rupture associated with multiple pelvic fractures. A vaginourethroplasty was performed as a salvage procedure, via intrapelvic anastomosis of the proximal urethra to the caudal vagina, following failure of a primary urethral anastomosis. Urinary diversion was achieved via tube cystostomy and a vagino-urethral catheter was maintained for 3 days postoperatively. Anterograde cystourethrography was performed at 7 days and 14 days postoperatively. Absence of contrast leakage from the vagino-urethral anastomosis was documented at 14 days postoperatively and the tube cystostomy was removed. An Escherichia coli urinary tract infection was treated following removal of the tube cystostomy and subsequent urine culture revealed no evidence of urinary tract infection. The cat retained normal urinary continence and elimination behaviour during the 7-month follow-up period. Vaginourethroplasty could be considered as a salvage option for management of traumatic pelvic urethral rupture in the neutered female cat.

Urethral obstruction in cats: predisposing factors, clinical, clinicopathological characteristics and prognosis

Feline lower urinary tract diseases in general, and urethral obstruction (UO) in particular, are common clinical conditions in cats. The aims of this study were to identify risk factors for UO, to characterise clinical and clinicopathological signs, outcome and recurrence, as well as risk factors for mortality and recurrence. Eighty-two cats with UO were compared to 82 sex and time matched controls. The mean age of cats with UO was significantly lower compared to controls, while the mean body weight was higher. The proportion of indoors-outdoors cats was significantly lower in the study group compared to the control group, and the proportion of cats consuming only dry food was higher. Overall mortality was 8.5%. Ionised calcium was significantly higher in survivors compared to non-survivors, and the prevalence of hypocalcaemia was lower. Recurrence in 6 months and 2 years were 22% and 24%, respectively. Cats with recurrence had significantly lower urine pH at presentation.

Frequency of urinary tract infection among dogs with pruritic disorders receiving long-term glucocorticoid treatment

OBJECTIVE

To determine frequency of urinary tract infection (UTI) among dogs with pruritic disorders that were or were not receiving long-term glucocorticoid treatment.

DESIGN

Observational study.

ANIMALS

127 dogs receiving glucocorticoids for > 6 months and 94 dogs not receiving glucocorticoids.

PROCEDURE

Bacterial culture of urine samples was performed in dogs receiving long-term glucocorticoid treatment, and information was collected on drug administered, dosage, frequency of administration, duration of glucocorticoid treatment, and clinical signs of UTI. For dogs not receiving glucocorticoids, a single urine sample was submitted for bacterial culture.

RESULTS

Multiple (2 to 6) urine samples were submitted for 70 of the 127 (55%) dogs receiving glucocorticoids; thus, 240 urine samples were analyzed. For 23 of the 127 (18.1%) dogs, results of bacterial culture were positive at least once, but none of the dogs had clinical signs of UTI. Pyuria and bacteriuria (present vs absent) were found to correctly predict results of bacterial culture for 89.9% and 95.8% of the samples, respectively. Type of glycocorticoid, dosage, frequency of administration, and duration of treatment were not associated with frequency of UTI. None of the urine samples from dogs not receiving glucocorticoids yielded bacterial growth. The frequency of UTI was significantly higher for dogs treated with glucocorticoids than for dogs that had not received glucocorticoids.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that dogs receiving long-term glucocorticoid treatment have an increased risk of developing a UTI. On this basis, we recommend that urine samples be submitted for bacterial culture at least yearly for such dogs.

In Vitro Efficacy of a Polyhexamethylene Biguanide-Impregnated Gauze Dressing Against Bacteria Found in Veterinary Patients

OBJECTIVE

To evaluate the in vitro efficacy of polyhexamethylene biguanide (PHMB)-impregnated gauze dressing in limiting the growth of bacteria both within and underneath the dressing.

STUDY DESIGN

In vitro study.

METHODS

Squares of PHMB-impregnated and control gauze were placed on agar plates inoculated with 1 of 11 bacterial species, including 8 multi-resistant organisms. Growth under the gauze was assessed qualitatively after 24-hour incubation. Repeated use of sponges was used to evaluate residual inhibitory activity against Micrococcus lutea and Staphylococcus schleiferi ss. schleiferi. In a second procedure, PHMB-impregnated and control gauze squares were placed in sterile plastic wells and inoculated with 1 of 5 bacterial species, including Pseudomonas spp. and Klebsiella spp. Inhibition of bacterial growth within and underneath the dressing after 24-hour incubation was evaluated by quantifying the numbers of bacteria on the well floor and within each square.

RESULTS

PHMB-impregnated gauze provided greater inhibition of growth of 4/4 Gram-positive species and 2/6 Gram-negative species on inoculated plates compared with control gauze. Residual inhibitory activity of PHMB-impregnated gauze was significantly greater against M. lutea on all days and against S. schleiferi ss. schleiferi on days 1 and 4 compared with control. No bacteria were recovered from inoculated PHMB-impregnated gauze squares placed in sterile wells or from the well floor underneath. More than 9 x 10(5) colony-forming units (CFU) were recovered from inoculated control samples placed in sterile wells and more than 8.4 x 10(4) CFU were recovered from control well floors.

CONCLUSION

PHMB-impregnated gauze dressing, when placed on inoculated agar plates, reduces growth of underlying bacteria, particularly Gram-positive species. Wet-inoculated PHMB-impregnated dressing prevents growth of Gram-positive and Gram-negative bacteria both within and underneath the dressing.

CLINICAL RELEVANCE

PHMB-impregnated dressings may be useful for reducing contamination of underlying wounds by bacterial pathogens.

Clinical use of low-profile cystostomy tubes in four dogs and a cat

Traditional cystostomy tubes (used for temporary or permanent diversion of urine in dogs and cats) are long (> or = 22 cm) and cumbersome to stabilize, requiring sutures or bandages to hold the tube against the body. Use of a low-profile gastrostomy port system as a low-profile cystostomy tube (LPCT) in 4 dogs and a cat was investigated; owner satisfaction with the device was assessed. Technical difficulty associated with placement and management of LPCTs was similar to that for traditional cystostomy tubes; with LPCTs, activity and mobility of pets was not compromised, and bandaging was not required. Complications included lower urinary tract infection, mild peristomal leakage of urine and leakage from components of the system, and subcutaneous peristomal infection. Four of 5 owners considered the tube to be easy to use; all owners said they would be comfortable repeating their decision to use the LPCT in their pet.

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.

Use and misuse of indwelling urethral catheters

Because indwelling urethral catheterization is potentially detrimental, especially when it leads to urinary tract infection, indwelling urinary catheters must not be used indiscriminately. Appropriate use of indwelling catheters in recently obstructed cats is accomplished by identifying which cats are likely to experience repeated obstruction if such catheterization is not performed. When indwelling catheters are used, precautions must be taken to minimize the occurrence and severity of catheter-associated complications. Following catheter removal, which should be done as soon as possible, urine culture results should be used to verify absence of infection or to guide treatment when infection is detected.

Pharmacologic management of feline lower urinary tract disorders

Pharmacological recommendations for the treatment of lower urinary tract disorders in cats are rapidly evolving as more is learned about the physiology and pathophysiology of the feline urinary bladder and urethra. Recent investigations and clinical observations have led to reconsideration of previously prescribed treatments and to the use of new and alternative pharmacologic agents. Pharmacologic agents used in the management of common lower urinary tract disorders in cats, including urinary tract infections, idiopathic lower urinary tract inflammation, urinary incontinence, urine retention, and urinary elimination disorders, are reviewed.

Feline perineal urethrostomy: a potential cause of feline lower urinary tract disease

Perineal urethrostomies are associated with complications that may mimic primary causes of feline lower urinary tract disorders. Though postoperative urethral strictures may be minimized by proficiency with an effective surgical technique, removal of the distal urethra may result in bacterial urinary tract infections in 25% to 30% of patients after surgery. Urinary tract infections caused by urease-producing microbes may induce struvite urolith formation. Thus the prophylactic benefits of minimizing recurrent urethral obstruction by urethrostomy must be weighed against a long-term predisposition to recurrent bacterial urinary tract infection and urolith formation.

Prednisolone therapy of idiopathic feline lower urinary tract disease: a double-blind clinical study

A double-blind clinical study was performed to evaluate prednisolone as treatment for idiopathic feline lower urinary tract disease. No differences in response were observed in prednisolone- and placebo-treated cats.

Management of nonobstructive idiopathic feline lower urinary tract disease

Consistently effective treatment and prevention of nonobstructive idiopathic lower urinary tract disease (LUTD) in male and female cats remains an enigma. Because clinical signs associated with this form are frequently self-limiting, considerable debate exists about the efficacy of various symptomatic therapies advocated for management of idiopathic feline LUTD. Any form of therapy might appear to be beneficial, as long as it was not harmful. The self-limiting nature of some forms of idiopathic feline LUTD underscores the need for controlled prospective double-blind clinical studies to prove the value of various forms of therapy.