Diagnosis of urinary tract infection in infants under 3 months with fever without a source: reliability of urinalysis and urine culture.

BACKGROUND: Urinary tract infection (UTI) is infants' most common serious bacterial infection. This study aimed to investigate the reliability of urianalysis (UA) to predict UTI, to specify the colony forming units (CFU)/ml threshold for diagnosis, and to identify variables that help suspect bacteremia in infants under 3 months with UTI. METHODS: We reviewed clinical records of children under 3 months hospitalized for a fever without source and recorded age, sex, days of fever pre-consultation, temperature and severity at admission, discharge diagnoses, laboratory tests, and treatments. According to the discharge diagnosis, we divided them into UTIs (-) and (+) with or without bacteremia. RESULTS: A total of 467 infants were admitted: 334 with UTI and 133 without UTI. In UTIs (+), the pyuria had a sensitivity of 95.8% and bacteria (+) 88.3%; specificity was high, especially for nitrites (96.2%) and bacteria (+) (92.5%). Positive predictive value (PPV) for nitrites was 95.9%, for bacteria 96.7%, and oyuria 92.5%. Escherichia coli was present in 83.8% of urine and 87% of blood cultures. UTIs with bacteremia had inflammatory urinalysis, urine culture > 100,000 CFU/ml, and higher percentage of C reactive protein (CRP) > 50 mg (p= 0.002); 94.6% of the urine culture had > 50,000 CFU. CONCLUSIONS: The pyuria and bacteria (+) in urine obtained by catheterization predict UTI. The cut-off point for diagnosis was ≥ 50,000 CFU/ml. No variables to suspect bacteremia were identified in this study.

INTRODUCCIÓN: La infección del tracto urinario (ITU) es una infección bacteriana grave frecuente en lactantes. El objetivo de este trabajo fue investigar la fiabilidad del análisis de orina (AO) para predecirla, precisar el umbral de unidades formadoras de colonias (UFC)/ml para el diagnóstico y buscar variables que ayuden a sospechar de bacteriemia en lactantes menores de 3 meses con ITU. MÉTODOS: Se revisaron fichas clínicas de lactantes menores de 3 meses hospitalizados por fiebre sin foco evidente, registrando edad, sexo, días de fiebre preconsulta, temperatura y gravedad al ingreso, diagnósticos de egreso, exámenes de laboratorio y tratamientos. Según diagnóstico de egreso, se separaron en ITU (-) y (+), con o sin bacteriemia. RESULTADOS: Ingresaron 467 lactantes: 334 con ITU y 133 sin ITU. En ITU (+), la sensibilidad de la piuria fue de 95.8% y bacterias (+) 88.3%; la especificidad fue alta para nitritos (96.2%) y bacterias (+) (92.5%). El valor predictivo positivo (VPP) fue de 95.9% para nitritos, 96.7% para bacterias y 92.5% para piuria. Escherichia coli se encontró en el 83.8% de los urocultivos (UC) (+) y en el 87% de los hemocultivos (+). Las ITU con bacteriemia presentaron elementos inflamatorios, UC con ≥ 100,000 UFC/ml y mayor porcentaje de proteína C reactiva (PCR) > 50 mg/l (p= 0.002); el 94.6% de los UC (+) tuvo ≥ 50,000 UFC/ml. CONCLUSIONES: La piuria y bacterias (+) en el AO son excelentes para pronosticar ITU en orina obtenida con sonda vesical y el punto de corte para el diagnóstico debe ser ≥ 50,000 UFC/ml. No encontramos señales que ayudaran a sospechar ITU con bacteriemia.

Nitrite-negative results in urinary tract infection by Enterobacterales: does the nitrite dipstick test have low sensitivity?

Urinary tract infection (UTI) is one of the most common bacterial infections among humans. Urine culture is the gold standard diagnostic method for UTI; however, the dipstick test for nitrite is a widely used method signalling the presence of urinary nitrate-reducing bacteria. Unlike the gold standard, the dipstick test is easy to perform, while it is also less time-consuming and less expensive, and produces a result in a few minutes. This study investigates the sensitivity of the dipstick test for nitrite compared with the Griess test in urine samples from UTI caused by Enterobacterales species. We used the Griess test, which is the gold standard in nitrite measurement, to determine the sensitivity of the nitrite dipstick test. Semiquantitative urine culture was performed using standard procedures, and Enterobacterales identification was performed by manual conventional biochemical tests. In the first sample selection, 3 % (8/267) of urine samples suspected of UTI, analysed from March to April 2016, were nitrite-negative by dipstick test but positive for Enterobacterales in the urine culture. In the second sample selection, 5 % (2/44) of urine samples from October to December 2022 were also nitrite-negative but showed urine Enterobacterales isolation. All nitrite-negative dipstick results were consistent with the Griess test. Escherichia coli was the most prevalent bacterium, followed by Klebsiella pneumoniae, independent of sample selection. The dipstick test is a safe alternative for investigating nitrite in urine samples. We believe that the cause of nitrite-negative results is a lack of dietary nitrate, dilution of urine and exogenous interference (e.g. ascorbic acid). These findings support the idea that standard urine culture is necessary to rule out UTI.

Leukocyte Esterase and Nitrite Urine Reagent Strip Utility Under Altered Assay Conditions in Dogs.

The study evaluated leukocyte esterase (LE) and nitrite reagent pad usefulness in canine urine using multiple time endpoints and decision thresholds. Whole and sedimented urine samples from 116 client-owned dogs were analyzed with reagent strips from four manufacturers. Results for LE and nitrite were recorded every 30 s up to 150 s using "trace" and "+" positive thresholds and compared to microscopic urine sediment analysis and culture results. Sedimented urine assessed at 150 s with a "trace" positive threshold for LE had significantly or trending higher sensitivity (brand dependent) for pyuria detection compared with manufacturer recommendations. Using these parameters, LE sensitivity and negative likelihood ratio were 66.67-89.47%, and 0.13-0.37, respectively. Following manufacturer recommendations, LE specificity and positive likelihood ratio were 96.91-100% and 17.02-30.63, respectively. Nitrite performance for pyuria and bacteriuria detection was poor for all conditions. LE reagent pads are a useful screening test for pyuria detection using sedimented urine and a "trace" positive threshold at 150 s, whereas LE use with traditional manufacturer recommendations is a good confirmatory test for pyuria detection. Nitrite reagent pads are not useful for pyuria or bacteriuria detection.

Diagnostic test accuracy of dipstick urinalysis for diagnosing urinary tract infection in febrile infants attending the emergency department.

OBJECTIVE: To report the diagnostic test accuracy of dipstick urinalysis for the detection of urinary tract infections (UTIs) in febrile infants aged 90 days or less attending the emergency department (ED). DESIGN: Retrospective cohort study. PATIENTS: Febrile infants aged 90 days or less attending between 31 August 2018 and 1 September 2019. MAIN OUTCOME MEASURES: The sensitivity, specificity and predictive values of dipstick urinalysis in detecting UTIs defined as growth of ≥100 000 cfu/mL of a single organism and the presence of pyuria (>5 white blood cells per high-power field). SETTING: Eight paediatric EDs in the UK/Ireland. RESULTS: A total of 275 were included in the final analysis. There were 252 (92%) clean-catch urine samples and 23 (8%) were transurethral bladder catheter samples. The median age was 51 days (IQR 35-68.5, range 1-90), and there were 151/275 male participants (54.9%). In total, 38 (13.8%) participants had a confirmed UTI. The most sensitive individual dipstick test for UTI was the presence of leucocytes. Including 'trace' as positive resulted in a sensitivity of 0.87 (95% CI 0.69 to 0.94) and a specificity of 0.73 (95% CI 0.67 to 0.79). The most specific individual dipstick test for UTI was the presence of nitrites. Including trace as positive resulted in a specificity of 0.91 (95% CI 0.86 to 0.94) and a sensitivity of 0.42 (95% CI 0.26 to 0.59). CONCLUSION: Point-of-care urinalysis is moderately sensitive and highly specific for diagnosing UTI in febrile infants. The optimum cut-point to for excluding UTI was leucocytes (1+), and the optimum cut-point for confirming UTI was nitrites (trace). TRIAL REGISTRATION NUMBER: NCT04196192.

Office-Based Urinalysis: A Comprehensive Review.

Comprehensive urinalysis involves inspection of the urine, dipstick chemical analysis, and microscopy and can be performed in the office setting. When testing for urinary tract infection, midstream urine should be collected using the clean-catch technique. A urine collection bag specimen can be used for clinically stable febrile infants with suspected urinary tract infection; however, the presence of leukocyte esterase or nitrites warrants more invasive urine collection. Urine specific gravity shows hydration status. Urinary pH levels can indicate diet, metabolism, or the presence of stones. Bilirubin and urobilinogen may suggest hepatobiliary disease or hemolysis. Glucosuria often indicates uncontrolled diabetes mellitus, and ketones suggest illness and inadequate nutrition. Hematuria on dipstick testing can be confirmed in the office using a spun urine sample. Proteinuria on dipstick testing should be followed by a quantitative test such as a spot urine albumin/creatinine ratio. In patients with symptoms of a urinary tract infection, the presence of nitrites is more specific for bacterial infection, and a positive leukocyte esterase result may occur from inflammation and infection. Asymptomatic bacteriuria is often unnecessarily treated in older patients. Without symptoms of urinary tract infection, urine culture is useful only in pregnancy and preparation for endoscopic urologic procedures.

Comparing Urine Specimen Collection Methods for Urinalysis and Culture Agreement: A Paired Sample Design.

OBJECTIVES: The primary aim of this study was to determine if results from clean catch urine specimens agree with results from catheterized specimens in a urogynecology patient population. The secondary aim was to identify clinical scenarios in which catheterized specimens are preferred over clean catch specimens. METHODS: Both a midstream clean catch and a catheterized specimen were obtained for each participant. Dipstick urinalysis was performed. If either specimen was positive for nitrites, leukocyte esterase, or blood then both were sent for urine culture.Kappa statistics were calculated to measure agreement between the paired specimen data for the total sample and for stratified samples. We agreed to accept clean catch results as preferable to catheterized results if the κ statistic was 0.7 or greater. RESULTS: Three hundred forty-two participants were enrolled. For all participants, the agreement between the paired samples was strong for nitrite (κ = 0.884), moderate for blood and colony count (both κ = 0.656), weak for culture species (κ = 0.566), and minimal for leukocyte esterase (κ = 0.382). When data were stratified for menopause, vaginal estrogen use, body mass index, and prolapse, there were no clinical scenarios in which the κ values were consistently greater than our accepted value of 0.7. CONCLUSIONS: Our data indicate that catheterized urine specimens should be used in the evaluation of urinary tract infection or microscopic hematuria in the typical patient presenting to a urogynecology office who is often menopausal, overweight, and may have prolapse.

Sex-Dependent Effects of Nephron Ift88 Disruption on BP, Renal Function, and Cystogenesis.

BACKGROUND: Primary cilia regulation of renal function and BP in health and disease is incompletely understood. This study investigated the effect of nephron ciliary loss on renal physiology, BP, and ensuing cystogenesis. METHODS: Mice underwent doxycycline (DOX)-inducible nephron-specific knockout (KO) of the Ift88 gene at 2 months of age using a Cre-LoxP strategy. BP, kidney function, and renal pathology were studied 2 and 9 months after DOX (Ift88 KO) or vehicle (control). RESULTS: At 2 months post-DOX, male, but not female, Ift88 KO, compared with sex-matched control, mice had reduced BP, enhanced salt-induced natriuresis, increased urinary nitrite and nitrate (NOx) excretion, and increased kidney NOS3 levels, which localized to the outer medulla; the reductions in BP in male mice were prevented by L-NAME. At 9 months post-DOX, male, but not female, Ift88 KO mice had polycystic kidneys, elevated BP, and reduced urinary NOx excretion. No differences were observed in plasma renin concentration, plasma aldosterone, urine vasopressin, or urine PGE2 between Ift88 KO and control mice at 2 or 9 months post-DOX. CONCLUSIONS: Nephron cilia disruption in male, but not female, mice (1) reduces BP prior to cyst formation, (2) increases NOx production that may account for the lower BP prior to cyst formation, and (3) induces polycystic kidneys that are associated with hypertension and reduced renal NO production.

Diagnostic Accuracy of Point-of-care Nitrite and Leukocyte Esterase Dipstick Test for the Screening of Pediatric Urinary Tract Infections.

Our study aimed to evaluate the diagnostic performance of point-of-care nitrite and leukocyte esterase (LE) dipsticks in the diagnosis of suspected urinary tract infection (UTI) in infants <6 months (young infants) versus older children. The secondary objectives were to study the dipstick efficacy in children with congenital anomalies of the kidney and urinary tract (CAKUT) versus those without CAKUT; in children with simple UTI versus complicated UTI; and to evaluate the clinico-microbiological profile of children presenting with UTI. In this prospective observational study, cases with suspected UTI were enrolled from pediatric emergency or outpatient departments. Urine was collected for performing the urine dipstick and culture. Descriptive data regarding CAKUT, age, gender, etc., were recorded in a predesigned pro forma. We screened 506 children with suspected UTI, of whom 221 had urine culture positive. Approximately 38.4% of the children with UTI had underlying CAKUT, while 7.6% had renal scars. The most common CAKUT was vesicoureteric reflux (VUR). About 12 patients (2.3%) were known to have CAKUT at the time of enrollment in the study. In infants <6 months, LE dipstick had sensitivity 92%, specificity 89.7%, positive predictive value (PPV) 86.7%, negative predictive value (NPV) 93.8%, likelihood ratio (LR) + 8.9, LR- 0.09. In infants <6 months, nitrite dipstick had sensitivity 38%, specificity 97%, PPV 90.4%, NPV 68%, LR+ 12.6 and LR-0.63. In the age group 6 months to 12 years, the efficacy was better for both dipsticks. In age group more than 6 months to 12 years, LE dipstick had sensitivity 96.4%, specificity 95.8%, PPV 94.8 %, NPV 97.2%, LR+ 22.9, LR- 0.04. In age group more than six months to 12 years, nitrite dipstick had sensitivity 94.7%, specificity 99.5%, PPV 99.3%, NPV 96%, LR+ 189.4, and LR-0.05.

Preoperative urine nitrite versus urine culture for predicting postoperative fever following flexible ureteroscopic lithotripsy: a propensity score matching analysis.

PURPOSE: Multiple studies have reported that preoperative positive urine culture is an independent risk factor for postoperative fever (POF) after ureteroscopy (URS). Urine nitrite is associated urinary tract infections (UTIs). However, none of studies has explored the role of urine nitrite in the prediction of POF after flexible URS (fURS). METHODS: Patients who underwent fURS by the same surgeon between 2009 and 2019 were screened. Sensitivity and specificity of urine culture and urine nitrite were calculated. Propensity score (PS) matching was performed to get a baseline-balanced retrospective cohort to avoid potential bias. Receiver operating characteristic-area under the curve (ROC-AUC) calculated was used to determine the predictive power of models. Decision curve analysis (DCA) was plotted to obtain the clinical benefit of the models. RESULTS: Poseoperative fever (POF) is defined as the temperature of the patient higher than 38 ℃ within 72 h after operation, with no sign of infection in other systems. 31(2.8%) of 1095 cases had POF after fURL. Urine nitrite had a better specificity than urine culture for POF diagnosis (P < 0.001). After the PS matching, a well-balanced cohort of 24 POF group and 96 no-POF group was produced. The mean AUC from the bootstrap resampling method for urine nitrite model (AUC: 0.8736; 95% CI: 0.8731-0.8743) was significantly increased than that of the urine culture model (AUC: 0.8385; 95% CI: 0.8378-0.8392). The application of two kinds of POF predicting models could bring clinical net benefit when the probability is < 35%. However, urine nitrite model showed a better clinical net benefit acquirement compared to the urine culture model. CONCLUSION: Preoperative positive urine nitrite may play a pivotal role in the prediction of POF after fURS and needs to be validated by future evidence.

Predicting Urinary Tract Infections With Interval Likelihood Ratios.

BACKGROUND: Protocols for diagnosing urinary tract infection (UTI) often use arbitrary cutoff values of urinalysis components to guide management. Interval likelihood ratios (ILRs) of urinalysis results may improve the test's precision in predicting UTIs. We calculated the ILR of urinalysis components to estimate the posttest probabilities of UTIs in young children. METHODS: Review of 2144 visits to the pediatric emergency department of an urban academic hospital from December 2011 to December 2019. Inclusion criteria were age <2 years and having a urinalysis and urine culture sent. ILR boundaries for hemoglobin, protein, and leukocyte esterase were "negative," "trace," "1+," "2+" and "3+." Nitrite was positive or negative. Red blood cells and white blood cells (WBCs) were 0 to 5, 5 to 10, 10 to 20, 20 to 50, 50 to 100, and 100 to 250. Bacteria counts ranged from negative to "loaded." ILRs for each component were calculated and posttest probabilities for UTI were estimated. RESULTS: The UTI prevalence was 9.2%, with the most common pathogen being Escherichia coli (75.2%). The ILR for leukocyte esterase ranged from 0.20 (negative) to 37.68 (3+) and WBCs ranged from 0.24 (0-5 WBCs) to 47.50 (100-250 WBCs). The ILRs for nitrites were 0.76 (negative) and 25.35 (positive). The ILR for negative bacteria on urinalysis was 0.26 and 14.04 for many bacteria. CONCLUSIONS: The probability of UTI in young children significantly increases with 3+ leukocyte esterase, positive nitrite results, 20 to 50 or higher WBCs, and/or many or greater bacteria on urinalysis. The probability of UTI only marginally increases with trace or 1+ leukocyte esterase or 5 to 20 WBCs. Our findings can be used to more accurately predict the probability of true UTI in children.

Pre-exposure to mechanical ventilation and endotoxemia increases Pseudomonas aeruginosa growth in lung tissue during experimental porcine pneumonia.

BACKGROUND: Immune system suppression during critical care contributes to the risk of acquired bacterial infections with Pseudomonas (P.) aeruginosa. Repeated exposure to endotoxin can attenuate systemic inflammatory cytokine responses. Mechanical ventilation affects the systemic inflammatory response to various stimuli. AIM: To study the effect of pre-exposure to mechanical ventilation with and without endotoxin-induced systemic inflammation on P. aeruginosa growth and wet-to-dry weight measurements on lung tissue and plasma and bronchoalveolar lavage levels of tumor necrosis factor alpha, interleukins 6 and 10. METHODS: Two groups of pigs were exposed to mechanical ventilation for 24 hours before bacterial inoculation and six h of experimental pneumonia (total experimental time 30 h): A30h+Etx (n = 6, endotoxin 0.063 µg x kg-1 x h-1) and B30h (n = 6, saline). A third group, C6h (n = 8), started the experiment at the bacterial inoculation unexposed to endotoxin or mechanical ventilation (total experimental time 6 h). Bacterial inoculation was performed by tracheal instillation of 1x1011 colony-forming units of P. aeruginosa. Bacterial cultures and wet-to-dry weight ratio analyses were done on lung tissue samples postmortem. Separate group comparisons were done between A30h+Etx vs.B30h (Inflammation) and B30h vs. C6h (Ventilation Time) during the bacterial phase of 6 h. RESULTS: P. aeruginosa growth was highest in A30h+Etx, and lowest in C6h (Inflammation and Ventilation Time both p<0.05). Lung wet-to-dry weight ratios were highest in A30h+Etx and lowest in B30h (Inflammation p<0.01, Ventilation Time p<0.05). C6h had the highest TNF-α levels in plasma (Ventilation Time p<0.01). No differences in bronchoalveolar lavage variables between the groups were observed. CONCLUSIONS: Mechanical ventilation and systemic inflammation before the onset of pneumonia increase the growth of P. aeruginosa in lung tissue. The attenuated growth of P. aeruginosa in the non-pre-exposed animals (C6h) was associated with a higher systemic TNF-α production elicited from the bacterial challenge.

Sensing of electrolytes in urine using a miniaturized paper-based device.

Analyzing electrolytes in urine, such as sodium, potassium, calcium, chloride, and nitrite, has significant diagnostic value in detecting various conditions, such as kidney disorder, urinary stone disease, urinary tract infection, and cystic fibrosis. Ideally, by regularly monitoring these ions with the convenience of dipsticks and portable tools, such as cellphones, informed decision making is possible to control the consumption of these ions. Here, we report a paper-based sensor for measuring the concentration of sodium, potassium, calcium, chloride, and nitrite in urine, accurately quantified using a smartphone-enabled platform. By testing the device with both Tris buffer and artificial urine containing a wide range of electrolyte concentrations, we demonstrate that the proposed device can be used for detecting potassium, calcium, chloride, and nitrite within the whole physiological range of concentrations, and for binary quantification of sodium concentration.

Urinalysis Using a Diaper-Based Testing Device.

Urinary tract infections (UTI), one of the most common bacterial infections, annually affect 150 million people worldwide. Infants and the elderly are likely to have missed or delayed diagnosis of UTI due to difficulty clearly describing their symptoms. A rapid screening method for UTI is a critical and urgent need for these populations. The aim of our study is to develop a diaper-based testing device to assay urine biomarkers including pH, leukocyte, and nitrite level. This all-in-one device assists in urine collection and testing using a colorimetric approach to provide easily read visual results on the outside surface of a test strip-integrated diaper. In this study, we tested samples from 46 patients using testing strips and examined the results from 7 patients recruited to validate the strip-integrated diaper. In conclusion, this new diaper-based testing device is easy to use, rapid, and inexpensive, all of which imbue it with tremendous potential for development into a commercially viable UTI screening system.

Renomedullary Interstitial Cell Endothelin A Receptors Regulate BP and Renal Function.

BACKGROUND: The physiologic role of renomedullary interstitial cells, which are uniquely and abundantly found in the renal inner medulla, is largely unknown. Endothelin A receptors regulate multiple aspects of renomedullary interstitial cell function in vitro. METHODS: To assess the effect of targeting renomedullary interstitial cell endothelin A receptors in vivo, we generated a mouse knockout model with inducible disruption of renomedullary interstitial cell endothelin A receptors at 3 months of age. RESULTS: BP and renal function were similar between endothelin A receptor knockout and control mice during normal and reduced sodium or water intake. In contrast, on a high-salt diet, compared with control mice, the knockout mice had reduced BP; increased urinary sodium, potassium, water, and endothelin-1 excretion; increased urinary nitrite/nitrate excretion associated with increased noncollecting duct nitric oxide synthase-1 expression; increased PGE2 excretion associated with increased collecting duct cyclooxygenase-1 expression; and reduced inner medullary epithelial sodium channel expression. Water-loaded endothelin A receptor knockout mice, compared with control mice, had markedly enhanced urine volume and reduced urine osmolality associated with increased urinary endothelin-1 and PGE2 excretion, increased cyclooxygenase-2 protein expression, and decreased inner medullary aquaporin-2 protein content. No evidence of endothelin-1-induced renomedullary interstitial cell contraction was observed. CONCLUSIONS: Disruption of renomedullary interstitial cell endothelin A receptors reduces BP and increases salt and water excretion associated with enhanced production of intrinsic renal natriuretic and diuretic factors. These studies indicate that renomedullary interstitial cells can modulate BP and renal function under physiologic conditions.

Preoperative positive urine nitrite and albumin-globulin ratio are independent risk factors for predicting postoperative fever after retrograde Intrarenal surgery based on a retrospective cohort.

BACKGROUND: To determine risk factors for postoperative fever (POF) after retrograding intrarenal surgery (RIRS) and a nomogram for prediction of POF in patients undertaking RIRS has been developed based on the risk factors found. METHODS: This is a retrospective designed-study. A continuous cohort from a single-center database that consisted of 1095 cases undertaking RIRS with complete preoperative medical records from January 2009 to December 2018 was obtained. Independent risk factors were identified according to the multi-variate logistics regression and a further nomogram was developed. The performance of the nomogram was evaluated through three aspects including net clinical benefit, calibration, and discrimination. RESULTS: A total of 31(2.8%) cases had POF after the RIRS. Risk factors included time in RIRS ≥30mins (only the flexible scope use period) (OR: 2.16, 95%CI; 1.01-4.62, P = 0.047), preoperative positive urine culture (OR: 2.55, 95%CI; 1.01-6.42, P = 0.047), preoperative positive urine nitrite (OR: 9.09, 95%CI; 2.99-27.64, P < 0.001), Albumin/globulin ratio (AGR) (OR: 0.14, 95%CI; 0.03-0.74, P = 0.020) were further included in the nomogram to predict the POF probability for individuals. The Hosmer-Lemeshow test showed a goodness-of-fit. The calibration curve demonstrated good agreement between observation and prediction. Decision curve analysis (DCA) demonstrated it was clinical use in RIRS. CONCLUSIONS: The preoperative urine nitrite, AGR, RIRS time, and preoperative urine culture are found to be independent risk factors associated with POF after RIRS. Then we have developed a nomogram taking these factors into account that accurately predicted POF after RIRS.

Nitric oxide-related markers link inversely to blood pressure in black boys and men: the ASOS and African-PREDICT studies.

Nitric oxide plays an important role in maintaining endothelial function, while increased oxidative stress may lead to nitric oxide inactivation and cardiovascular disease. If nitric oxide biosynthesis/bioavailability is already suppressed early in life, it may potentially predispose an individual to the early development of cardiovascular disease. We therefore aimed to identify differences in nitric oxide-related markers (urinary nitrate, nitrite and the nitrate-to-nitrite ratio (UNOxR)) between young black and white individuals, and whether these markers are associated with blood pressure and carotid intima media thickness. We included black and white healthy boys (n = 80; aged 6-8 years) and men (n = 510; 20-30 years) and measured blood pressure and carotid intima media thickness, along with urinary biochemical markers including nitrate and nitrite. The black boys and men had lower nitrate and UNOxR (all p ≤ 0.003) than their white counterparts. In single and multiple regression analyses, we found an inverse association of diastolic blood pressure in the black boys (adj. R2 = 0.27; ß = -0.32; p = 0.030), and systolic blood pressure in black men (adj. R2 = 0.07; ß = -0.13; p = 0.036) with nitrate. Carotid intima media thickness associated inversely with UNOxR in the black men (adj. R2 = 0.02; ß = -0.14; p = 0.023), but not in the boys. Lower urinary nitrate in black boys and young men was associated negatively with blood pressure, suggesting that potentially lower nitric oxide bioavailability in young black individuals may contribute to hypertension development in later life.

New participant stratification and combination of urinary biomarkers and confounders could improve diagnostic accuracy for overactive bladder.

Overactive bladder (OAB) is a highly prevalent symptom complex characterised by symptoms of urinary urgency, increased frequency, nocturia, with or without urge incontinence; in the absence of proven infection or other obvious pathology. The underlying pathophysiology of idiopathic OAB is not clearly known and the existence of several phenotypes has been proposed. Current diagnostic approaches are based on discordant measures, suffer from subjectivity and are incapable of detecting the proposed OAB phenotypes. In this study, cluster analysis was used as an objective approach for phenotyping participants based on their OAB characteristic symptoms and led to the identification of a low OAB symptomatic score group (cluster 1) and a high OAB symptomatic score group (cluster 2). Furthermore, the ability of several potential OAB urinary biomarkers including ATP, ACh, nitrite, MCP-1 and IL-5 and participants' confounders, age and gender, in predicting the identified high OAB symptomatic score group was assessed. A combination of urinary ATP and IL-5 plus age and gender was shown to have clinically acceptable and improved diagnostic accuracy compared to urodynamically-observed detrusor overactivity. Therefore, this study provides the foundation for the development of novel non-invasive diagnostic tools for OAB phenotypes that may lead to personalised treatment.

Fast and Sensitive: Automated Point-of-Care Urine Dips.

OBJECTIVE: Point-of-care (POC) urine dipstick is a highly used test in the pediatric emergency department (PED) owing to its fast turn-around time and inexpensive cost. Past studies have shown hand-held urine dipsticks and automated urinalysis in children younger than 48 months to be sensitive predictors for urinary tract infection (UTI). It is hypothesized that POC dip testing is as accurate as laboratory urinalysis in the diagnosis of UTI. METHODS: A retrospective chart review was conducted on patients (aged birth through 18 years) presenting to a PED between January 2015 and December 2015. Eligible subjects included those that had a POC dip, laboratory urinalysis (lab UA), and urine culture performed during their PED visit. Subjects were selected, using a random number generator; 334 charts were selected. A positive POC dip was defined as having a positive leukocyte esterase or the presence of nitrites. A positive lab UA was defined as having a positive leukocyte esterase, nitrites, or greater than 10 white blood cells per high-power field. Urine culture was used as the criterion standard for comparison. RESULTS: A total of 334 subjects' charts were reviewed. Sensitivity and specificity of the POC dip were 91.4% (95% confidence interval [CI], 76.9%-98.2%) and 63.9% (95% CI, 57.2%-69.3%); lab UA, 91.4% (95% CI, 76.9%-98.2%) and 63.9% (95% CI, 58.2%-69.3%); and lab dip, 88.6% (95% CI, 73.3%-96.8%) and 65.6% (95% CI, 59.9%-70.9%). CONCLUSIONS: Point-of-care dips are as sensitive in detecting UTI as the lab UA. A prospective study could allow for further demographic evaluation of POC dip diagnosed UTI.

Should the Absence of Urinary Nitrite Influence Empiric Antibiotics for Urinary Tract Infection in Young Children?

OBJECTIVES: Screening for urinary tract infection (UTI) includes urinary nitrite testing by dipstick urinalysis. Gram-negative enteric organisms produce urinary nitrite and represent the most common uropathogens. Enterococcus, a less common uropathogen, does not produce nitrite and has a unique antibiotic resistance pattern. Whether to adjust empiric antibiotics in the absence of urinary nitrite has not been established. Our primary objective was to determine prevalence of enterococcal UTI among young children with a nitrite negative urinalysis. METHODS: A retrospective study of children aged less than 2 years evaluated in the emergency department for possible UTI and had a paired urinalysis and urine culture was performed. Urinary tract infection was defined by catheterized culture yielding greater than or equal to 50,000 colony-forming units per milliliter of a single uropathogen. Prevalence of uropathogens among nitrite negative samples was studied. RESULTS: A total of 7599 children were studied. Median (interquartile range) age was 5.6 (2.3-11.2) months, and 57% were female. Prevalence of UTI was 8.1%. Enterococcus was the uropathogen in 2.1% of UTIs, and all cases had negative dipstick nitrite. Among nitrite negative UTIs, 95.6% of uropathogens were gram-negative and only 3.2% (confidence interval, 1.8%-5.3%) were enterococcus. None of the 200 UTIs with positive nitrite yielded enterococcus (upper confidence interval, 1.4%). Among children with positive leukocyte esterase and negative nitrite, only 0.7% of cases had enterococcal UTI. CONCLUSIONS: Only 3% of nitrite negative UTIs were caused by enterococcus. Given the low prevalence of enterococcal UTI, the absence of dipstick nitrite should not affect routine empiric antibiotic choice for presumptive UTI in young children.