Evaluation of modified Wright-staining of dried urinary sediment as a method for accurate detection of bacteriuria in cats

Romanowsky staining: history, recent advances and future prospects from a chemistry perspective

Romanowsky staining was an important methodological breakthrough in diagnostic hematology and cytopathology during the late 19th and early 20th centuries; it has facilitated for decades the work of biologists, hematologists and pathologists working with blood cells. Despite more than a century of studying Romanowsky staining, no systematic review has been published that explains the chemical processes that produce the "Romanowsky effect" or "Romanowsky-Giemsa effect" (RGE), i.e., a purple coloration arising from the interaction of an azure dye with eosin and not due merely to their simultaneous presence. Our review is an attempt to build a bridge between chemists and biomedical scientists and to summarize the available data on methylene blue (MB) demethylation as well as the related reduction and decomposition of MB to simpler compounds by both light and enzyme systems and microorganisms. To do this, we analyze modern data on the mechanisms of MB demethylation both in the presence of acids and bases and by disproportionation due to the action of light. We also offer an explanation for why the RGE occurs only when azure B, or to a lesser extent, azure A is present by applying experimental and calculated physicochemical parameters including dye-DNA binding constants and electron density distributions in the molecules of these ligands. Finally, we discuss modern techniques for obtaining new varieties of Romanowsky dyes by modifying previously known ones. We hope that our critical literature study will help scientists understand better the chemical and physicochemical processes and mechanisms of cell staining with such dyes.

Incidence of feline idiopathic cystitis and urethral obstruction during COVID-19 human movement restrictions in Queensland, Australia

OBJECTIVES

Feline idiopathic cystitis (FIC) and urethral obstruction (UO) are commonly linked to increased stress. The influence of human movement restrictions on their incidence remains undetermined. FIC with or without UO is associated with environmental stress factors. The severe acute respiratory syndrome coronavirus 2 (COVID-19) pandemic restricted human movement and working behaviours. It is unknown if these restrictions increased the risk of FIC or UO in cats.

METHODS

Total cat emergency accessions and transfers between 8 February 2019 and 8 February 2021 at two private hospitals were retrospectively reviewed. Cats were included in the FIC group if they presented with lower urinary tract signs and supporting urinalysis, and were included in the UO group if they presented with UO. Cats with current urinary tract infection, or previous FIC or UO, were excluded. Groups were considered 'pre-COVID-19' between February 2019 and 2020 and 'COVID-19' between February 2020 and 2021. Cases of FIC and UO were compared between COVID-19 and pre-COVID-19 using Fisher's exact test and relative risk (RR) calculations.

RESULTS

The pre-COVID-19 incidence of FIC was 4.3% (63/1477, 95% confidence interval [CI] 0.0332-0.053), non-obstructive FIC was 1.4% (20/1477, 95% CI 0.008-0.020) and UO was 2.9% (43/1477, 95% CI 0.020-0.038). One cat was excluded as obstruction occurred during hospitalisation. The COVID-19 incidence of FIC was 5.4% (113/2081, 95% CI 0.044-0.64), non-obstructive FIC was 2.1% (70/2081, 95% CI 0.014-0.027) and UO was 3.4% (70/2081, 95% CI 0.026-0.042). The risk of non-obstructive FIC (P = 0.122; RR 0.652, 95% CI 0.387-1.096), UO (P = 0.382; RR 0.839, 95% CI 0.577-1.22) or either (P = 0.098; RR 0.773, 95% CI 0.572-1.044) was not significantly higher in the COVID-19 period than the pre-COVID-19 period.

CONCLUSIONS AND RELEVANCE

No clear association between COVID-19 movement restrictions and the incidence of UO or non-obstructive FIC was found within this retrospective population.

[Urinalysis in dogs and cats, part 2: Urine sediment analysis]

Examination of the urine sediment is part of a routine urinalysis and is undertaken in order to identify insoluble particles in the urine. This procedure is mainly used in the context of diagnostic evaluation of urinary tract diseases, but may also be useful for the diagnosis of systemic diseases and intoxications. Analysis of fresh urine is recommended as changes in cell morphology, cell lysis and in vitro crystal formation may occur in the course of its storage. Manual urine sediment analysis is still performed in many veterinary practices. Native wet-mount preparations are suitable for the identification and quantification of urine sediment particles. The examination of stained wet-mount preparations or air-dried smears may be necessary to further differentiate cells and to identify bacteria. For several years, automatic urine sediment analyzers have been available in veterinary medicine. These save considerable time and staff resources, however verification of the automatically generated results by an experienced observer remains necessary. Urine sediment particles that are frequently identified and clinically relevant include red blood cells, white blood cells, different types of epithelial cells, crystals, and casts as well as bacteria. Furthermore, parasite eggs, fungal hyphae, lipid droplets, spermatozoa, fibres, hair, mucus, plant parts or environmental contaminations may be found in the urine sediment and result in a complication of the result interpretation.

Urine bacterial culture growth and association with urine sedimentation and clinical findings in cats with acute kidney injury

OBJECTIVES

A urine culture is often pursued in cats with acute kidney injury (AKI) to screen for bacterial growth in the urine, but it can be cost prohibitive. The aim of the study was to determine the ability of a urinalysis and lower urinary tract signs (LUTS) to predict urine culture results in cats with AKI.

METHODS

Ninety-seven cats with AKI were included in this study. This was a retrospective, observational study. Medical records from 2008 to 2018 were reviewed to identify cats with AKI that had a paired urinalysis and urine bacterial culture. The sensitivity, specificity, positive predictive value and negative predictive values of microscopic bacteriuria, pyuria, hematuria and the presence of LUTS for predicting urine culture results was calculated.

RESULTS

Thirty-two percent of cats (n = 31) had a positive urine culture. Of these, 28 (90%) had bacteriuria, 21 (68%) had pyuria, 13 (42%) had hematuria and 10 (32%) had LUTS. Of the 42 cats without hematuria or pyuria, seven had a positive urine culture (17%). Bacteriuria had a high sensitivity (90%) and specificity (92%) for predicting urine culture bacterial growth. The absence of bacteriuria had a high negative predictive value for no bacterial growth (95%). The odds of a positive urine culture were increased with bacteriuria (odds ratio [OR] 114, 95% confidence interval [CI] 29-621; P <0.001), pyuria (OR 21, 95% CI 7-70; P <0.001) and LUTS (OR 5, 95% CI 1.7-16; P = 0.004). Hematuria was not associated with a positive culture (sensitivity 42%, specificity 52%).

CONCLUSIONS AND RELEVANCE

Microscopic bacteriuria and pyuria on urine sediment evaluation and LUTS can be helpful for predicting bacterial culture results in cats with AKI and in settings where submitting a urine culture may not be financially feasible.

Comparison of the Anvajo Vet Fluidlab 1 urine sediment analyzer to manual microscopy and Idexx SediVue analysis for analysis of urine samples from cats and dogs

The Vet Fluidlab 1 (Anvajo), a new urine sediment analyzer for use in veterinary medicine, uses holographic microscopy to detect urine sediment particles in uncentrifuged urine. We compared the performance of the Fluidlab to manual microscopy and Idexx SediVue analysis for the detection of RBC, WBC, epithelial cells (EC), struvite crystals (STR), all crystals (CRY), and casts (CST) in urine samples from cats and dogs. The performance of the Fluidlab for the detection of bacteria was compared to bacterial culture. We included 624 urine samples from feline (238; 38%) and canine (386; 62%) patients; 227 samples had been submitted for bacterial culturing. The sensitivity of the Fluidlab compared to manual microscopy was 92.1% for RBC, 90.1% for WBC, 87.5% for EC, 67.6% for STR, 53.9% for CRY, and 12.5% for CST. Specificity was >97% for STR and CST, 90.0% for CRY, 78.4% for WBC, 59.4% for EC, and 55.1% for RBC. Sensitivities and specificities of the Fluidlab for analytes compared to manual microscopy were found to be similar to those obtained by the Fluidlab compared to SediVue analysis. Miscellaneous materials (e.g., lipid droplets, sperm, cell detritus) seemed to be the main reason for the high false-positive rate in RBC and EC classification by the Fluidlab. Detection of bacteria by the Fluidlab compared to bacterial culture had a sensitivity of 89.8% and a specificity of 72.3%. The performance of the Fluidlab is acceptable for the detection of WBC and bacteria; sensitivity for the detection of CRY and CST, and specificity for the detection of RBC and EC, require improvement.

Urinary Cytology: Potential Role in Canine Urinary Tract Infections

The diagnosis of urinary tract infections (UTIs) requires a concomitant evaluation of clinical signs and urine culture, which is of fundamental to start an appropriate antibiotic treatment. Several factors, such as subclinical bacteriuria or pre-analytical errors, may make the interpretation of urine culture difficult. The aim of the study was to evaluate the association between the finding of neutrophils and bacteria in unstained and stained canine urine sediment and the presence of clinical signs and positive urine culture. Urine samples from 35 dogs with clinical signs of UTI and 55 asymptomatic dogs with risk factors for UTI were prospectively collected by cystocentesis, divided into three aliquots, and submitted for: (1) physical and chemical Dipstick analysis and unstained urinary sediment (casts, crystals, bacteria, leucocytes, cells, parasites); (2) stained urinary sediment (extra/intracellular bacteria, degenerated and non-degenerated neutrophils); (3) qualitative and quantitative urine culture and antimicrobial sensitivity-test. The association between unstained and stained findings of urinary sediment and urine culture was tested. Sensibility, specificity, and positive/negative predictive values in diagnosing positive urine cultures of bacteria at unstained and stained evaluation were compared. Both wet-mount bacteriuria and the cytological presence of intracellular and extracellular bacteria, neutrophils, and degenerated neutrophils were successively associated with positive urine culture (p < 0.001). The presence of intracellular bacteria was the only independent predictor of positive urine culture. Total bacterial count did not differ significantly between symptomatic and asymptomatic dogs. Detection of extracellular and intracellular bacteriuria at stained urinary sediment significantly improved the sensibility of predicting positive urine culture. Cytologic evaluation of urinary sediment may be helpful in detecting signs of active inflammation, thus enhancing the clinical relevance of a positive urine culture.

Evaluation of Heller's reaction and the urine dipstick method alone or in combination to detect proteinuria in sheep

BACKGROUND

Urine dipstick and Heller's reaction are easy first-line screening tests for the detection of proteinuria; however, the performance of these methods in alkaline ovine urine is largely unknown.

OBJECTIVE

The aim of this study was to evaluate the diagnostic performance of Heller's reaction alone or in combination with dipstick for the detection of proteinuria in sheep, using the urine protein to creatinine ratio (UP/C) with two cut-off values as the reference method.

METHODS

Ninety-eight urine samples were collected from sheep using the transient apnea method. Heller's reaction, the dipstick method, and the UP/C ratio were used to assess proteinuria. The results were statistically analyzed twice, based on two different UP/C cut-off values of 0.2 and 0.5. Cohen's kappa value was used to determine the agreement between the UP/C ratios and Heller's reaction, the dipstick method, or the combination of methods. Sensitivity, specificity, and positive and negative likelihood ratios were calculated. ROC curves were also generated, and the areas under the curve (AUC) were evaluated to determine the optimal threshold for the numerical values of the two methods.

RESULTS

Heller's reaction is more specific (96.67% and 96.00% when the cut-off value is 0.2 and 0.5, respectively) than the dipstick method, while the dipstick method was more sensitive (91.18% and 91.30%, when the cut-off value was 0.2 and 0.5, respectively) than Heller's reaction for the detection of proteinuria. Both tests were accurate when any grade >0 was considered positive.

CONCLUSIONS

Proteinuria can almost be excluded in ovine urine samples with negative Heller's reaction and dipstick test.

Effect of urine-specific gravity on performance of bacteriuria in predicting urine culture results

OBJECTIVE

To determine the effect of urine-specific gravity (USG) on using microscopic evaluation of bacteriuria to predict urine culture results in dogs and cats.

MATERIALS AND METHODS

We performed a retrospective medical record review of canine and feline patients that had a urinalysis and urine culture performed simultaneously. The sensitivity, specificity, positive predictive value and negative predictive value of microscopic bacteriuria for predicting urine culture results were calculated, stratified by USG. Multivariable regression was performed to test the effect of USG, pyuria, haematuria and species on the agreement between microscopic bacteriuria and culture results.

RESULTS

A total of 481 dogs and 291 cats with paired urinalysis and urine culture results were included in the study. Microscopic bacteriuria had moderate sensitivity (76% in dogs, 64% in cats) and high specificity (97% in dogs, 96% in cats) for predicting urine culture bacterial growth. Samples with rod bacteria were more likely to have bacterial growth than those with cocci (OR=Infinity, 95% CI 4.8 - Infinity). As compared to isosthenuric+hyposthenuric samples (USG ≤1.012), agreement was lower in moderately concentrated (OR=0.44, 95% CI 0.19 to 0.91) samples. Absence of bacteriuria, pyuria and haematuria had a high negative predictive value for no bacterial growth (96%).

CLINICAL SIGNIFICANCE

Microscopic bacteriuria has a high specificity in predicting urine culture results, regardless of USG. The finding that microscopic bacteriuria has better agreement with urine culture results in isosthenuric+hyposthenuric urine argues against reflex culture in these samples, especially if pyuria and haematuria are also absent. Urine microscopy can aid clinicians in determining the likelihood of urine culture growth.

Using the Idexx SediVue Dx to predict the need for urine bacteriologic culture in cats

We analyzed urine samples from 191 cats for bacteriuria with an automated urine sediment analyzer (Idexx SediVue Dx), combined with image review by an observer, and compared to bacteriologic culture results. Sixty-nine samples were unambiguously assigned to be free of bacteria by the instrument and the observer, and no bacterial growth was detected. Twenty-seven samples were unambiguously assigned to have bacteriuria; 24 of these 27 samples were culture-positive. For these samples, bacteriuria was predicted with a sensitivity of 100% and a specificity of 96%. A clear assignment was not possible for 95 samples, 81 of which were culture-negative. Specificity dropped to 45% when all samples were considered. Using the automated leukocyte count to predict bacteriuria, sensitivity was 82% and specificity was 75%. Automated sediment analysis is faster and less observer-dependent than sediment analysis under a microscope, but accurate detection of bacteriuria remains difficult in a large proportion of samples. Bacteriuria was significantly associated with leukocyte count; the leukocyte count was >5/high power field in 82% of culture-positive samples.

Development of a method for creating antibiograms for use in companion animal private practices

OBJECTIVE

To identify a method for developing antibiograms for use in companion animal private practices (PPs).

SAMPLES

Reports (n = 532) of aerobic bacterial culture and antimicrobial susceptibility testing performed between January 1, 2018, and December 31, 2018, at 11 PPs and 1 academic primary care practice (APCP).

PROCEDURES

Data extracted from reports included patient identification number, laboratory accession number, patient signalment, collection method, body site, and results of bacterial culture and antimicrobial susceptibility testing. A custom antibiogram was then constructed with the help of commonly available software by adapting methods used by human hospitals. Susceptibility patterns of bacteria isolated by PPs and the APCP were compared to identify challenges associated with collating data from multiple laboratories.

RESULTS

4 bacterial species (Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, and Staphylococcus pseudintermedius) and 3 bacterial groups (Enterobacteriaceae, Enterococcus spp, and coagulase-positive Staphylococcus spp) met the minimum requirement of ≥ 15 isolates for construction of an antibiogram. For urine samples, 3 bacterial species and 2 bacterial groups met the minimum requirement of ≥ 10 isolates. For samples from skin, 2 bacterial species and 2 bacterial groups met the minimum requirement of ≥ 10 isolates. Patient signalment, sample source, and distribution of bacterial isolates were similar between PP and APCP patients.

CONCLUSIONS AND CLINICAL RELEVANCE

Results demonstrated that it was feasible to adapt existing guidelines for developing antibiograms in human medicine to the veterinary outpatient setting. Use of antibiograms could aid in empirical antimicrobial drug selection in a manner that supports antimicrobial stewardship principles.

Potential Acute Renal Injury in Sheep with Bluetongue Serotype 4

Bluetongue is a vector-borne disease with epidemic potential. Recently, outbreaks of Bluetongue were reported across Greece, caused by the Bluetongue virus (BTV) serotype 4. Regarding its pathogenesis, BTV infection involves various target organs with limited data referring to the kidneys. The objective of this study was to identify the possible impact of BTV infection on kidneys using common renal biomarkers. Urine and blood samples collected from 30 sheep with clinical signs of bluetongue (BTV sheep) and 30 clinically healthy sheep (normal sheep) from the same farms were finally selected and included in the study from an initial population of 47 sheep per group, based on the absence of active urine sediment. Complete urinalysis was performed and urine protein to creatinine ratio (UPC) and urine gamma-glutamyl transferase to creatinine (UGGTC) ratio were determined. Blood urea nitrogen (BUN), creatinine, total proteins, albumin (ALB), and inorganic phosphate (P) were determined in serum samples. UPC and UGGTC were significantly higher (p < 0.05) in BTV sheep compared to normal, whereas urine specific gravity (USG) was significantly lower (p < 0.05). Cylindruria was also detected in BTV sheep, and absence of azotemia in BTV and normal sheep. All these findings are indicative of renal tubular injury and/or dysfunction and suggestive of an association between BTV infection and acute damage of renal tissue.

Risk factors for urinary bacterial growth in dogs with congenital portosystemic shunts: 66 cases (1997-2019)

OBJECTIVE

To identify risk factors for urinary bacterial growth in dogs with confirmed congenital portosystemic shunts on which a quantitative urine culture was performed.

MATERIALS AND METHODS

Sixty-six dogs were included in this retrospective cross-sectional study. Medical records were reviewed from 1997 through 2019. Variables of interest included age, sex and sexual status, clinical signs for a urinary tract infection, blood urea concentration, urinalysis abnormalities, ultrasound abnormalities of the urinary tract, and previous treatment. Univariable and multivariable analyses were performed.

RESULTS

The median age of the dogs was one year (range: 0.2-11.0 years). Urinary tract ultrasound abnormalities (cystic calculi and cystic debris) were reported in 50 dogs (75.7%). Abnormalities on urinalysis included pyuria in nine dogs (13.6%), bacteriuria in 13 dogs (19.7%), and haematuria in 26 dogs (39.4%). The median urine specific gravity was 1.021 (range: 1.004-1.052). Sixteen dogs (24.2%) had a positive quantitative urine culture. Based on multivariable analysis, bacteriuria (Odds ratio, 116; 95% CI, 9.6-1393; P = < 0.001) was the only variable significantly associated with a significantly increased odds for a positive quantitative urine culture.

CLINICAL SIGNIFICANCE

Clinical and subclinical bacteriuria can occur in dogs with congenital portosystemic shunts. In this group of dogs, bacteriuria was a risk factor for urinary bacterial growth.

Urinary tract infection and subclinical bacteriuria in cats: A clinical update

PRACTICAL RELEVANCE

Urinary tract infection (UTI) is an important cause of feline lower urinary tract disease (FLUTD), particularly in female cats older than 10 years of age. In addition to cats with typical clinical signs of FLUTD or upper UTI, many cats have subclinical bacteriuria, but the clinical relevance of this is currently uncertain. UTIs are one of the most important indications for antimicrobial use in veterinary medicine and contribute to the development of antimicrobial resistance. Adherence to treatment guidelines and confinement to a few first-line antimicrobial agents is imperative to avoid further deterioration of the antimicrobial resistance situation. The decision to treat with antimicrobials should be based on the presence of clinical signs, and/or concurrent diseases, and the results of urine culture and susceptibility testing.

CLINICAL CHALLENGES

Distinguishing between cats with bacterial cystitis, and those with idiopathic cystitis and concurrent clinical or subclinical bacteriuria, is challenging, as clinical signs and urinalysis results may be identical. Optimal treatment of subclinical bacteriuria requires clarification as there is currently no evidence that demonstrates a beneficial effect of routine treatment. Management of recurrent UTIs remains a challenge as evidence for most alternatives used for prevention in cats is mainly anecdotal, and no preventive treatment modality is currently recommended.

EVIDENCE BASE

This review draws on an extensive literature base in veterinary and human medicine, including the recently updated guidelines of the International Society for Companion Animal Infectious Diseases for the diagnosis and management of bacterial urinary tract infections in dogs and cats. Where published evidence is lacking, the authors describe their own approach; notably, for the bacteriuric cat with chronic kidney disease.

Encrusted Cystitis with Suspected Ureteral Obstruction Following Cystoscopic-Guided Laser Ablation of Ectopic Ureters in a Dog

A 1 yr old 30 kg spayed female Labrador retriever presented for stranguria and hematuria 3 wk after cystoscopic laser ablation for ectopic ureters. Encrusted cystitis was diagnosed based on ultrasonography, cystoscopy, urinalysis, and culture of Corynebacterium urealyticum from the urine. Unilateral hydronephrosis and hydroureter were suspected to be secondary to obstruction at the trigone. The dog was treated with focal debridement of plaques at the left ureter, urinary acidification, and long-term antibiotic therapy with complete recovery. This is the first report of encrusted cystitis as a complication of cystoscopic-guided laser ablation for ectopic ureters, and suggests cystoscopic debridement may be useful if ureteral obstruction occurs.

Practical urinalysis in the cat: 2: Urine microscopic examination 'tips and traps'

SERIES OUTLINE

This is the second article in a two-part series on urinalysis in the cat. The specific focus is urine microscopic examination. Part 1, which appeared in the March 2016 issue, discussed urine macroscopic examination.

PRACTICAL RELEVANCE

Urinalysis is an essential procedure in feline medicine but often little attention is paid to optimising the data yielded or minimising factors that can affect the results.

CLINICAL CHALLENGES

For the best results, appropriately collected urine should be prepared promptly by specialist laboratory personnel for the relevant tests and assessed by a clinical pathologist. This is invariably impractical in clinical settings but careful attention can minimise artefacts and allow maximum useful information to be obtained from this seemingly simple process.

AUDIENCE

Clinical pathologists would be familiar with the information provided in this article, but it is rarely available to general or specialist practitioners, and both groups can potentially benefit.

EQUIPMENT

Most of the required equipment is routinely available to veterinarians. However, instructions have been provided to give practical alternatives for specialist procedures in some instances.

EVIDENCE BASE

The evidence base for feline microscopic urinalysis is quite poor and information has largely been extrapolated from the human literature. Information from feline studies has been included where available. In addition, practical clinicopathological and clinical observations are provided.

Subclinical bacteriuria in cats: prevalence, findings on contemporaneous urinalyses and clinical risk factors

Objectives Subclinical bacteriuria (SB) is bacterial colonization of the urinary tract in the absence of clinical signs. The purposes of this study were to determine the prevalence of SB in cats and to describe results of the contemporaneous urinalysis. Secondarily, patient characteristics associated with SB were compared with those for cats without SB. Methods An electronic search identified all urine cultures performed on cats at a teaching hospital between 2009 and 2015. Results were subcategorized based on the presence or absence of lower urinary tract disease (LUTD) and SB-positive cases identified. The first control population was from samples without LUTD. The second control population was from all samples not identified as a SB-positive sample, including subclinical negative samples and those with LUTD. Five controls for each SB-positive sample were selected for both control groups. Medical records for all groups were reviewed. Results In all, 31/500 (6.2%) subclinical samples were positive. Most infections were a single organism (n = 27); four contained multiple organisms. Escherichia coli was the most common species (58%) followed by Enterococcus species (25%). Positive specimens were more likely to be from female cats (n = 24) vs male (n = 7; P = 0.0054). SB was strongly associated with bacteriuria (60% vs 6%; P <0.0001) and pyuria (67% vs 19%; P <0.0001). Positive specimens were significantly more likely to have an abnormal sediment examination (odds ratio 13.5, P <0.0001). When compared with all specimens including those with LUTD, SB was significantly associated with a lower urine specific gravity (1.022 vs 1.030; P = 0.0256) and presence of chronic kidney disease (68% vs 46%; P = 0.0168). Conclusions and relevance In this study, SB appears to be uncommon in cats and, in most cases, is associated with an abnormal urine sediment examination. Based on this study, there is little indication to perform a culture in a cat with no clinical signs of LUTD and an unremarkable sediment examination.

Urinalysis

Performing a urinalysis should be part of a minimum database in addition to physical examination, historical information gathering, complete blood cell counts, and serum/plasma biochemical analysis. Urinalysis provides information on function of various organs and information on renal function. It is necessary to interpret blood urea nitrogen and serum/plasma creatinine concentrations and is useful in assessing urine concentrating and diluting ability, glomerular barrier function, tubular function, proteinuria, discolored urine, urolithiasis, and neoplasia. Performing a urinalysis is technically easy and does not require expensive equipment or disposable supplies.

Antimicrobial susceptibility in bacterial isolates from Norwegian cats with lower urinary tract disease

Studies of feline lower urinary tract disease (FLUTD) among Norwegian cats have shown higher prevalences of bacterial cystitis than most previously published reports. The aims of the present study were to identify bacterial isolates obtained from the urine of Norwegian cats with FLUTD and their susceptibility to antimicrobial agents. Eighty-two bacterial isolates from 72 urine cultures obtained from 71 different cats were included. Escherichia coli, Staphylococcus species, Enterococcus species and Streptococcus species were the most frequently detected. The percentages of isolates susceptible to the included antimicrobial agents were as follows: enrofloxacin - 92%; trimethoprim/sulfonamide - 91%; nitrofurantoin - 89%; tetracycline - 78%; ampicillin - 73%; amoxicillin/clavulanic acid - 72%; trimethoprim - 68%; amoxicillin - 58%; cephalexin - 51%; spiramycin - 39%; penicillin - 34%; fucidic acid - 34%; lincomycin - 27%. Although several tendencies towards increasing antimicrobial resistance were detected among the isolates included, the species of bacteria isolated and their patterns of antimicrobial resistance were, in general, in concurrence with the existing literature. Thus, the results do not fully explain the higher prevalence of bacterial cystitis found in Norwegian cats. Moreover, additional explanatory factors beside the inclusion of primary accession cases rather than referred cases were not found.

Evaluation of a catalase-based urine test for the detection of urinary tract infection in dogs and cats

BACKGROUND

Bacterial infection of the urinary tract is a common disorder in dogs and cats. Although microscopic examination of urine sediment is routinely used to screen for infection, this test can lack sensitivity or require expertise. A reliable in-clinic screening test would be a useful adjunct for the identification of dogs and cats with bacterial urinary tract infection (UTI).

HYPOTHESIS

That a catalase-based urine test (Accutest Uriscreen™) is a more sensitive screening test for UTI in dogs and cats than urine microscopic sediment examination.

ANIMALS

One hundred and sixty client-owned dogs and cats.

METHODS

Surplus urine from animals presented to a veterinary teaching hospital was used in this prospective observational study. A routine urinalysis, aerobic bacterial culture, and the Uriscreen test were performed on cystocentesis samples. Sensitivity and specificity with 95% confidence intervals and positive and negative likelihood ratios were calculated for Uriscreen and microscopic sediment examination using culture results as the gold standard.

RESULTS

Bacterial culture was positive in 27/165 (16.4%) samples. The sensitivity, specificity, and positive and negative likelihood ratios for the Uriscreen were 89%, 71%, 3.0, and 0.15, respectively. Sensitivity, specificity, and positive and negative likelihood ratios for urine sediment microscopic examination were 78%, 90%, 7.8, and 0.24, respectively.

CONCLUSIONS AND CLINICAL IMPORTANCE

The Uriscreen is a more sensitive screening test for UTI in dogs and cats than sediment examination; however, the urine sediment examination was more specific. A negative Uriscreen result helps exclude UTI; however, urine bacterial culture is still necessary to exclude or confirm UTI in all cases.

Evaluation of urinalyses from untreated adult cats with lower urinary tract disease and healthy control cats: predictive abilities and clinical relevance

This case-controlled study evaluated urinalyses from 111 primary cases diagnosed with feline lower urinary tract disease (FLUTD) and 101 healthy control cats. Urine samples were analysed by standardised procedures, and differences between the two groups were compared by multivariable logistic regression analysis, while controlling for age, body weight, gender and reproductive status. Further, the ability of using urine sediment findings to predict bacteriuria was evaluated. In addition, urinalyses from cats with bacterial cystitis, idiopathic cystitis, urolithiasis and urethral plugs were compared. The main findings were that increasing body weight was significantly associated with increased odds of FLUTD, while the influence of age and reproductive status was of less importance. Increasing amounts of red blood cells and epithelial cells were significantly associated with increased odds of FLUTD. The predictive ability of using bacterial sediment findings to predict bacterial growth was dependent on subjective grading of the amount of bacteria in the sediment and was, at best, only moderate. The few significant differences found between the different FLUTD diagnoses were of limited diagnostic value.

UTIs in small animal patients: part 2: diagnosis, treatment, and complications

There are multiple considerations when making a treatment plan for patients with urinary tract infections (UTIs). In part 2 of this review the authors discuss the clinical signs, diagnosis, treatment, and complications associated with bacterial UTIs in dogs and cats. Part 1 of this review summarized etiology and pathogenesis (see the Jan/Feb 2013 issue of the Journal of the American Animal Hospital Association).

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.