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

La citologia urinaria nel management delle infezioni del tratto urinario (UTI) nel cane Urine cytology in the menagement of canine urinary tract infections

Nella gestione attuale delle infezioni del tratto urinario (UTI) si consiglia di porre molta attenzione al corretto inquadramento del ruolo dei batteri, soprattutto per evitare l’uso inutile di antibiotici. In medicina veterinaria, per il lavaggio bronco-alveolare ed i versamenti cavitari, è riportato che le modificazioni degenerative neutrofiliche e la localizzazione intracellulare dei batteri abbiano rilevanza diagnostica nell’interpretazione del ruolo dei batteri nell’infezione. Il principale scopo di questo studio prospettico è quello di confrontare i risultati dell’urinocoltura ed il rilievo di alterazioni morfologiche neutrofiliche o di batteri intracellulari su preparati colorati in cani con sospette UTI o con fattori di rischio concomitanti. Il sospetto di UTI si è basato sull’anamnesi e sui segni clinici (es. pollachiuria, disuria ed ematuria). Ogni campione è stato prelevato per cistocentesi e sottoposto ad analisi chimica urinaria, valutazione del sedimento, urinocoltura, conta batterica totale ed antibiogramma come routinario approccio per il sospetto di UTI. I preparati citocentrifugati e colorati con Diff-Quik, sono stati microscopicamente valutati per la presenza/assenza di neutrofili e batteri, le alterazioni citomorfologiche neutrofiliche e localizzazione batterica (intra/extracellulare). Le urinocolture con <100 unità formanti colonia sono state considerate come negative. La presenza/assenza di neutrofili degenerati, batteri e la localizzazione batterica sono stati comparati con la positività/negatività all’esame colturale usando il test esatto di Fisher. Settantanove campioni sono stati prospettivamente inclusi. 29 campioni sono risultati positivi all’urinocoltura (22,9%). Le performance diagnostiche dello striscio a fresco e di quello colorato nella rilevazione della batteriuria, sono stati comparate. In accordo con altri studi, la citologia colorata mostra una maggiore specificità, VPP e VPN.30 campioni hanno mostrato la presenza di batteri alla valutazione citologica, di cui 24 con batteri intracellulari. I pazienti con batteri citologicamente evidenti hanno mostrato una probabilità 13 volte maggiore di avere un’urinocoltura positiva (OR 13,78 95% CI 4,536 - 41,867; p = 0.000), che aumenta ulteriormente se sono evidenziati batteri intracellulari (OR 17,1 95% CI 5,150 - 56,774; p = 0.000). 37 cani hanno mostrato neutrofili, in particolare, 32 con caratteristiche di degenerazione. La presenza di neutrofili fornisce una probabilità 4 volte maggiore di avere un’urinocoltura positiva 95% CI 1,618 - 11,499; p=0.003), mentre la presenza di degenerazione neutrofilica fornisce OR=12 (95% CI 3–40; p=0.0005). Cinque cani (3,95%) con batteri intracellulari e neutrofili degenerati hanno manifestato un colturale negativo. Segni clinici specifici di UTI, presenti in 24/79 cani, non sono risultati essere significativamente associati con la presenza di batteri, sia alla citologia che al colturale. Sulla base dei nostri risultati, la probabilità di avere un’urinocoltura positiva aumenta con il rilievo di batteri intracellulari e neutrofili degenerati. La loro presenza in preparati citologici può dunque essere un supporto nel management delle UTI canine e potrebbe essere utile soprattutto a svelare i falsi negativi all’urinocoltura. In veterinary medicine, stained urinary sediment evaluation has shown higher diagnostic performance than wet-mount evaluation in diagnosis of urinary tract infections (UTIs). For bronchoalveolar lavage and body cavity fluids, it is reported that degenerative neutrophil changes, and intracellular bacterial localization have known diagnostic relevance in evaluating the role of bacteria in inflammation. The main aim of this prospective study is to evaluate associations between urine culture and the detection of neutrophil morphological alterations or intracellular bacteria in stained urinary sediment in dogs with clinically suspected UTI or with concurrent risk factors. UTIs were suspected based on clinical history and clinical signs (such as pollakiuria, dysuria, and hematuria). Each dog had cystocentesis and underwent routine-urinalysis with wet-mount sediment evaluation, urine culture, bacterial cell count, and antibioticsensitivity test for their routine care for suspected UTI. Diff-Quik stained cytospin samples were microscopically evaluated for the presence/absence of neutrophils and bacteria, neutrophil morphological alterations, and bacterial localization (intra/extracellular). Urine culture with <100 colony-forming units were classified as negative. Presence/absence of degenerated neutrophils, bacteria and bacterial localization were compared between positive/negative urine culture using Fisher’s exact test. Seventy-nine samples were prospectively included. 29 samples result in positive urine culture (22,9%). The diagnostic performances of wet-mount and stained-mount sediment evaluation in detecting bacteriuria were compared. According to other studies, cytology shows a greater specificity, PPV and NPV.30 samples showed bacteria at cytospin evaluation, of which 24 had intracellular bacteria. Dogs showing cytologically-evident bacteria had a 13-fold chance to have positive urine culture (OR 13,78 95% CI 4,536 - 41,867; p = 0.000), which increases if intracellular bacteria were highlighted (OR 17,1 95% CI 5,150 - 56,774; p = 0.000). 37 dogs showed neutrophils, in particular, 32 dogs had degenerated neutrophils. Dogs having neutrophils had a 4-fold probability to have positive urine culture (95% CI 1,618 - 11,499; p=0.003), whereas if degenerated changes were present the OR=12 (95% CI 3–40; p=0.0005). Interestingly, 5 dogs (3,95%) with degenerated neutrophils and intracellular bacteria had negative urine culture. Specific clinical signs of UTIs weren’t significantly associated with the presence of active inflammation observed in the stained-mount sample. Based on our results, the probability to have urine culture positivity increases if intracellular bacteria and degenerated neutrophils are seen. Their presence in stainedmount samples may help in the management of dog UTIs. Most importantly, in some cases it allows to identify an active infection even with negative urine culture

An Association between Pancreatic and Cholestatic Biliary Disorders in Dogs

Canine chronic biliary tree disease (CBTD) is a suspected risk factor for pancreatic injury. The aim of this study was to evaluate the frequency and features of pancreatic involvement in canine CBTD, and their relationship with hyperlipemia and its severity. CBTD was defined as the increase in at least two of ALP, GGT, total bilirubin, cholesterol, and a biliary tree abnormal abdominal ultrasound (graded mild to severe). Pancreatic ultrasound appearance was recorded and classified as acute/chronic. Dogs were divided into a PBD group (pancreatic and biliary disease) and BD group (only biliary tree disease). PBD group was subgraded into a “pancreatic injury” and “pancreatitis” group. Eighty-one dogs were retrospectively included: 56 in the PBD group and 25 in the BD group. Of the PBD group, 20 had pancreatitis (15 chronic and 5 dogs acute). US score was mild in 64 dogs and moderate in 17 dogs, and it was not associated with evidence of pancreopathy. Sixty-six dogs had hyperlipemia (mild = 27 dogs; moderate-to-severe = 39 dogs) and no association with pancreopathy was found. Pancreatic injury was more frequent than pancreatitis in CBTD dogs. Although both acute and chronic pancreatic injury may be present, chronic forms were more frequent. Pancreatic injury should be considered in CBTD patients due its possible clinical significance

Serum Amino Acids Imbalance in Canine Chronic Hepatitis: Results in 16 Dogs

In humans, chronic liver disease may cause alterations in amino acids (AAs) metabolism, with serum branched-chain AAs (BCAAs) decreasing and aromatic AAs (AAAs) increasing. A reduced Fischer ratio (BCAAs/AAAs) has been found to be associated with hepatic fibrosis and is useful for assessing prognosis in human patients. In veterinary medicine, few studies have been performed, and in contrast to human patients, dogs with different kinds of hepatopathy tend to show both increased AAAs and BCAAs. In dogs, the association between histological scores and serum AAs has not been previously investigated. The aim of this study was to evaluate serum AAs in dogs with chronic hepatitis (CH) compared with a healthy control group (C) and, among CH dogs, in relation to their histological fibrosis and necroinflammatory activity scores. Leftover serum samples of 16 dogs with histological CH and 25 healthy dogs were employed. Serum AAs were measured by high performance liquid chromatography. Proline and the AAAs phenylalaine and tyrosine progressively increased with the histological severity. In contrast, cysteine, tryptophan and BCAA isoleucine progressively reduced. Lysine and the BCAAs leucine and valine showed a non-linear trend with the histological findings. The BCAAs/AAAs ratio was significatively reduced if higher grades of liver fibrosis were present