Clinicopathologic and pathologic findings of herpesvirus-induced urinary tract infection in conventionally reared cats

Clinicopathologic manifestations of induced infection of the feline lower urinary tract with bovid herpesvirus-4 (BHV-4, strain FCAHV) were characterized in 6 conventionally reared adult cats (2 sexually intact males, 2 castrated males, and 2 females). Two additional control cats were exposed with noninfected cell culture control inoculum. Clinical and radiographic signs of lower urinary tract disease were not observed in exposed or control cats. Microscopic hematuria was detected in urine samples collected by cystocentesis from 4 to 6 exposed cats and 1 of 2 control cats. Results of culture of urine for bacteria, mycoplasmas, ureaplasmas, and viruses were consistently negative. Low titer of serum BHV-4 (strain FCAHV)-neutralizing antibodies was detected in 4 of 6 exposed cats, but not in controls. Gross abnormalities of the urinary tract were not observed in any cat. Light microscopic examination of serial sections of the lower urinary tract revealed mild focal lymphoid cystitis in 2 of 6 exposed cats, one of which also had increased amounts of connective tissue and proliferation of blood vessels in the urinary bladder lamina propria. Ninety days after initial exposure, BHV-4 (strain FCAHV) was reisolated from explanted urinary bladder tissues of 5 of 6 exposed cats. Virus was not isolated from tissues of control cats. It was concluded that BHV-4 (strain FCAHV) establishes persistent urinary tract infection in conventionally reared adult male and female cats. However, persistent BHV-4 infection in cats may remain clinically inapparent.     

Genetic and serologic analysis of feline cell-associated herpesvirus-induced infection of the urinary tract in conventionally reared cats

The genetic and antigenic nature of feline cell-associated herpesvirus (FeCAHV) was characterized by use of DNA restriction endonuclease analysis, and direct and indirect fluorescent antibody (FA) techniques. Serologic responses of 6 conventionally reared cats with induced FeCAHV urinary tract infection were retrospectively evaluated, using an indirect FA test. The EcoRI, HindIII, and Pst I restriction endonuclease cleavage patterns of FeCAHV DNA were similar to those of bovid herpesvirus 4 (BHV-4; DN599 strain) DNA. Specific fluorescence was observed when FeCAHV-inoculated cell monolayers were reacted with fluorescein-conjugated BHV-4 (DN599 strain) antiserum. Conversely, specific fluorescence was also observed when feline anti-FeCAHV serum and fluorescein-conjugated caprine anti-feline IgG was reacted with BHV-4 (DN599 strain)-infected cell monolayers. At postinoculation week 10, serum antibody titer in cats with FeCAHV-induced urinary tract infection ranged from 1:2,560 to 1:10,240, as measured by use of indirect FA testing. It was concluded that FeCAHV is a member of the BHV-4 group. In addition, the FeCAHV indirect FA test provides a sensitive and specific means of evaluating FeCAHV antibody concentration in exposed cats.     

Prevalence of bacterial urinary tract infection after perineal urethrostomy in cats.

It has been reported that the prevalence of bacterial urinary tract infection (UTI) increases after perineal urethrostomy in male cats. Perineal urethrostomy, using a surgical technique preserving striated urethral sphincter function, was performed on 2 groups of cats. The first group consisted of healthy castrated cats. The second group of cats had recurrent or persistent urethral obstruction. All cats had normal urethral sphincter function after surgery, as measured by urethral pressure profilometry and electromyography. Long-term periodic urinalysis and bacterial culturing of urine was performed on all cats. Twenty-two percent of the previously obstructed cats had recurrent bacterial UTI, compared with none of the healthy cats. On the basis of these findings, we suggest that perineal urethrostomy per se does not predispose cats to bacterial UTI, but surgical alteration of the urethral meatus combined with an underlying uropathy may increase the prevalence of ascending bacterial UTI after surgery.     

Frequency and risk factors for urinary tract infection in cats with diabetes mellitus

BACKGROUND: Identification and control of infections are important in the management of diabetic cats. Urinary tract infections have not been well characterized in diabetic cats. This retrospective study was performed to review and characterize urinary tract infections in diabetic cats. HYPOTHESIS: Urinary tract infections are common in diabetic cats. ANIMALS: A review was made of the medical records of 141 diabetic cats that had had urine obtained for culture by antepubic cystocentesis and that had not been treated with antibiotics, undergone urinary tract catheterization or urinary tract surgery within 2 weeks of urine collection or had urethral obstruction at the time of urine collection. METHODS: A review of medical records. RESULTS: Urinary tract infection was identified in 18 of 141 diabetic cats. Escherichia coli was the most common isolate (67%). Female cats were at increased risk (prevalence odds ratios [POR], 3.7; 95% confidence interval [CI], 1.3 to 10.2; P = .013). Clinical signs of lower urinary tract disease and findings on urine sediment examination were good predictors of positive urine cultures. CONCLUSIONS AND CLINICAL IMPORTANCE: Urinary tract infections are common in diabetic cats regardless of status of diabetic control, suggesting routine monitoring with urine sediment exams or urine culture is warranted.     

Pathogenesis of acute toxoplasmosis in specific-pathogen-free cats

Systemic toxoplasmosis was produced in specific-pathogen-free cats by intravenous inoculation with Toxoplasma gondii tachyzoites. Infectious organisms were recovered from all tissues studied, but the number of organisms recovered from liver, lungs and spleen was 10-fold to 10,000-fold higher than from heart and brain. The occurrence and severity of Toxoplasma-induced lesions correlated with the number of infectious organisms recovered from the various tissues. In nonlymphoid tissues, the Toxoplasma-associated lesions consisted of multifocal necrosis, usually with demonstrable organisms. Lesions in the spleen and mesenteric lymph nodes consisted of reticuloendothelial and lymphoid hyperplasia, with few demonstrable organisms. Pneumonitis was severe and sometimes fatal in the early stages of systemic toxoplasmosis. Light- and electron-microscopic studies showed that the earliest lung lesions were randomly distributed infiltrates of neutrophils, eosinophils, and mononuclear cells into alveolar walls. Later lesions were diffuse alveolar necrosis, pneumocytic hyperplasia, and extensive fibrinocellular exudates in alveoli. Tachyzoites were present in cytoplasmic vacuoles of fibroblasts, macrophages, type I and II pneumocytes, bronchiolar epithelial cells, bronchiolar smooth muscle cells, endothelial cells, neutrophils, and eosinophils, and circulating monocytes. Replication of organisms was found in all parasitized cell types except neutrophils and eosinophils.     

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

ABSTRACT

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.     

A herd level analysis of urinary tract infection in dairy cattle

Cystitis, urethritis and pyelonephritis in cattle most commonly result from ascending urinary tract infection with Corynebacterium renale, Corynebacterium cystidis, Corynebacterium pilosum or Escherichia coli. We describe the clinical, bacteriological, clinical-pathological and epidemiological findings in a dairy cattle herd with urinary tract infection (UTI). Blood and urine samples from 17 calves and 19 cows were submitted to laboratory examinations. Depression, muscle wasting, weakness and frequent urine dribbling were the main characteristics of UTI in calves. Affected cows showed weight loss and an abrupt reduction in feed intake and milk production. Enlargement of the left kidney and loss of normal lobulation were evident on rectal examination. E. coli was the most frequent cause of UTI but C. renale, alpha-haemolytic Streptococcus spp., Proteus spp. Pseudomonas aeruginosa, Klebsiella spp. and Oligella urethralis were isolated as well. Differences in total protein and several protein fractions were found between affected and healthy animals.     

Nutrition and lower urinary tract disease in cats.

Lower urinary tract disease occurs commonly in cats and is often associated with crystal-related disease. Dietary modification is beneficial in managing some of these diseases, including idiopathic cystitis, urolithiasis, and urethral matrix-crystalline plugs. Altering dietary formulation may result in decreasing urinary concentrations of crystallogenic compounds, increasing urinary concentrations fo crystallogenic inhibitors, and diluting urine composition.     

Dried solidified blood calculi in the urinary tract of cats

We have noted an increased number of calculi submitted to the Gerald V. Ling Urinary Stone Analysis Laboratory, University of California, Davis, that do not contain crystalline material but appear to be composed of dried solidified blood (DSB). Canine and feline laboratory records from 1986-2003 were reviewed for samples composed of >99% DSB. No calculi from dogs were found, but specimens from 49 cats were composed of >99% DSB, of which almost half (n = 22) had been submitted after 2001. The DSB calculi had been removed surgically or by postmortem examination from all areas of the upper and lower urinary tract. All samples were well formed and could be divided in half with Rongeur forceps. Detailed case information was available for 12 cats. Urinalyses were available for 9 of the 12 cats, and the mean specific gravity was 1.017 (range, 1.009-1.032). Red blood cells were reported in the sediment of all cats, with most containing >100 RBC/hpf. Ureteral obstructions but no radio-opaque calculi were visible by radiography, including radiographic contrast studies. Reports of ultrasound examinations were available for 10 cats, and discrete calculi were not recorded. In addition to polarized light microscopy, infrared spectroscopy and electron probe microanalysis were performed on a subset (n = 6, DSB calculi; n = 3, control calculi) of samples. Significantly more carbon, nitrogen, and sulfur (P = .012, P = .02, and P = .012, respectively) were present in the elemental analysis of the DSB calculi than in the control calculi, suggesting that the DSB calculi are primarily formed from organic material. At this time, we are uncertain why these DSB calculi become solidified, and we recommend that samples be submitted both in formalin and preservative free to further investigate their etiology.     

Bacterial species isolated from cats with lower urinary tract infection and their susceptibilities to cefovecin

Background

The aim of this study was to determine the bacterial species recovered from 61 cats with lower urinary tract infection (LUTI), and their susceptibility to cefovecin in vitro.

Results

The clinical signs and final clinical diagnosis for cats with confirmed LUTI were also reported. After physical examination of the cats, urine samples including ≥5-6 leucocytes in microscopic evaluation were cultured using bacteriological techniques. The isolates were identified by conventional microbiological methods and tested for in vitro susceptibility using the Kirby-Bauer disc diffusion method recommended by the Clinical Laboratory Standards Institute. Bacterial growth was observed in 16 of 61 urine samples. Antimicrobial susceptibility tests showed that 13 of 16 (81%) isolates were susceptible to cefovecin. The most frequently isolated bacterium from cats with signs of lower urinary tract infection, was Escherichia coli.

Conclusion

Cefovecin was found to be effective in cats with LUTI. Because cefovecin is a new antimicrobial agent in veterinary medicine, there are only few studies about urine culture of cats with LUTI. It is the first study on in vitro activity of cefovecin against bacterial isolates from cats with lower urinary infections in Istanbul, Turkey.     

Corynebacterium urealyticum urinary tract infection in dogs and cats: 7 cases (1996-2003)

OBJECTIVE: To identify clinical features of Corynebacterium urealyticum urinary tract infection in dogs and cats and antimicrobial susceptibility patterns of C urealyticum isolates. DESIGN: Retrospective study. ANIMALS: 5 dogs and 2 cats. PROCEDURE: Medical records of dogs and cats for which C urealyticum was isolated from urine samples were reviewed. Isolates from clinical cases, along with previously lyophilized unsubtyped isolates of Corynebacterium spp collected between 1977 and 1995, were examined and, if subtyped as C urealyticum, tested for antimicrobial susceptibility. RESULTS: Signalment of infected animals was variable. Prior micturition disorders were common, and all animals had signs of lower urinary tract disease at the time C urealyticum infection was diagnosed. Median urine pH was 8.0; WBCs and bacteria were variably seen in urine sediment. In vitro antimicrobial susceptibility testing of 14 C urealyticum isolates revealed that all were susceptible or had intermediate susceptibility to chloramphenicol, tetracycline, and vancomycin and most were susceptible to enrofloxacin. Thickening of the bladder wall and accumulation of sediment were common ultrasonographic findings. Contrast radiography or cystoscopy revealed findings consistent with encrusting cystitis in 3 dogs. Infection resolved in 2 dogs following surgical debridement of bladder plaques and antimicrobial administration. In 2 other dogs and 1 cat treated with antimicrobials, infection with C urealyticum resolved, but urinary tract infection with a different bacterial species developed. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that preexisting urinary tract disorders are common in dogs and cats with C urealyticum infection. Treatment with appropriate antimicrobials in combination with surgical debridement might eliminate C urealyticum infection.     

Clinical evaluation of cats with lower urinary tract disease.

In a prospective study, 141 cats with hematuria, dysuria, urethral obstruction, or combinations of these signs were evaluated by contemporary diagnostic methods and compared with 26 clinically normal cats (controls). Specific diagnosis was established in 45% (64/141) of cats affected with lower urinary tract disease (LUTD). Crystalline matrix plug-induced urethral obstruction was diagnosed in 21% (30/141) of affected cats, uroliths were identified in 21% (30/141) of affected cats, uroliths with concomitant bacterial urinary tract infection (UTI) were identified in less than 2% (2/141) of affected cats, and bacterial UTI alone was identified in less than 2% (2/141) of cats with LUTD. Viruses, mycoplasmas, and ureaplasmas were not isolated from urine samples collected from affected or control cats. Bovine herpesvirus 4 (BHV-4)-neutralizing antibodies were not detected in any serum sample obtained from cats with LUTD or from control cats. In contrast, BHV-4 antibodies were detected by an indirect immunofluorescent antibody (IFA) test in sera obtained from 31% (44/141) of cats with LUTD and 23% (6/26) of control cats. The prevalence of positive BHV-4 IFA test results in affected cats was not significantly different from that observed in control cats. Significant association was not apparent between positive BHV-4 IFA test results and clinical diagnosis, abnormal laboratory findings, or cat age. However, the number of male cats with BHV-4 IFA titer was significantly (P less than 0.02, chi 2 test) greater than that of female cats. Detection of BHV-4 antibodies in approximately 30% of affected and control cats indicates prior virus exposure. Further investigations are warranted to clarify the specific role of BHV-4 in cats with naturally acquired LUTD.     

Adrenal gland function in dogs given methylprednisolone

Serum cortisol (hydrocortisone) was measured by radioimmunoassay in dogs given methylprednisolone (MP) orally or methylprednisolone acetate (MPA) IM. The MP was given on a daily and on an alternate-day basis to different treatment groups and the MPA was administered weekly. Samples of blood were obtained twice a week over a 9-week treatment period for serum cortisol determination, and the adrenal gland response to ACTH was assessed on posttreatment days 1, 3, 5, and 7. Administration of MP on an alternate or daily basis caused a slight but significant (P < 0.05) depression in mean resting cortisol values over time. The MPA administration caused a severe depression of resting serum cortisol values. In response to ACTH, cortisol values invariably increased sharply in nontreated control dogs and in those dogs given MP on an alternate-day basis. Dogs given MP daily had a depressed response to ACTH. The MPA treatment resulted in adrenal cortices that were unresponsive to ACTH. Dogs given MPA, but not challenge exposed with ACTH, had markedly lowered cortisol values for at least 2 weeks after cessation of treatment. Consequently, a difference between daily- and alternate-day MP administration was detected after ACTH challenge exposure; MPA administration inhibited adrenal cortisol secretion for at least the duration of the experiment.