Urinary vanin-1 for predicting acute pyelonephritis in young children with urinary tract infection: a pilot study.

BACKGROUND: Vanin-1, an epithelial glycosylphosphatidylolinositol (GPI)-anchored pantetheinase, is a valuable marker of renal injury. PURPOSE: The aim of this study was to assess the predictive value of vanin-1 in acute pyelonephritis (APN) in comparison to the conventional serum inflammatory markers in children aged 1-24 months with the first episode of urinary tract infection (UTI). MATERIAL AND METHODS: Urinary vanin-1, vanin-1/Cr ratio, WBC, CRP, PCT were analysed in 58 children with febrile UTI and in 18 children with non-febrile UTI. Febrile UTI group was divided into APN subgroup (n = 29) and non-APN subgroup (n = 29), based on the results of Tc-99m-ethylenedicysteine scan. RESULTS: The mean vanin-1 level was higher in the APN group compared to the non-febrile UTI group (p = 0.02) and did not differ between APN and non-APN subgroup. In univariate analysis, vanin-1 (p = 0.042), CRP (p < 0.001), PCT (p < 0.001), and WBC (p = 0.022), were associated with APN, but only vanin-1 (p = 0.048) and CRP (p = 0.002) were independent markers of APN. In ROC analysis, vanin-1, with its best cut-off value of 16.53 ng/mL, had worse diagnostic profile (AUC 0.629, sensitivity 58,6%, specificity 63.8%) than CRP, PCT and WBC (AUC: 0.937; 0.880; 0.667, respectively). CONCLUSIONS: Vanin-1 is not useful for predicting APN, since its diagnostic value is inferior to other conventional serum inflammatory markers.

Symptom- and urinalysis-based approach to diagnosing urinary tract infections in children with neuropathic bladders.

BACKGROUND: Accurately diagnosing urinary tract infections (UTI) in children with neuropathic bladders can be difficult given the lack of specificity of both clinical symptoms and routine screening tests. We aimed to identify a priori unknown classes/groups of children with neuropathic bladder with respect to symptoms and UA results and examine their relationships with odds of UTI. METHODS: We used latent class analysis (LCA) to identify unobserved classes/groups of children with neuropathic bladder based on symptoms and urinalysis (UA) results, respectively. Demographic and clinical data were gathered by retrospective chart review of a cohort with neuropathic bladder. Symptoms and UA results were obtained by chart review of visits where urine culture was ordered. RESULTS: Around 193 patients were included in UA results analysis and 179 in symptom-based analysis. Two latent classes of patients were identified with respect to symptoms, labeled "pyelonephritis class" and "cystitis class," and two, with respect to UA results, were labeled "positive UA class" and "negative UA class." The pyelonephritis class had significantly higher odds of UTI compared to the asymptomatic class. While odds of UTI in cystitis class were higher than the asymptomatic class, this difference was not statistically significant. Positive UA class had significantly higher odds of UTI compared to negative UA class. CONCLUSION: Two unobserved classes/groups exist in children with neuropathic bladder with respect to symptoms, corresponding to cystitis and pyelonephritis, and two classes of UA results that correspond with either a positive or negative UA. Our results suggest a differential approach to treatments may be considered.

Acute Pyelonephritis in Adults: Rapid Evidence Review.

Acute pyelonephritis is a bacterial infection of the kidney and renal pelvis and should be suspected in patients with flank pain and laboratory evidence of urinary tract infection. Urine culture with antimicrobial susceptibility testing should be performed in all patients and used to direct therapy. Imaging, blood cultures, and measurement of serum inflammatory markers should not be performed in uncomplicated cases. Outpatient management is appropriate in patients who have uncomplicated disease and can tolerate oral therapy. Extended emergency department or observation unit stays are an appropriate option for patients who initially warrant intravenous therapy. Fluoroquinolones and trimethoprim/sulfamethoxazole are effective oral antibiotics in most cases, but increasing resistance makes empiric use problematic. When local resistance to a chosen oral antibiotic likely exceeds 10%, one dose of a long-acting broad-spectrum parenteral antibiotic should also be given while awaiting susceptibility data. Patients admitted to the hospital should receive parenteral antibiotic therapy, and those with sepsis or risk of infection with a multidrug-resistant organism should receive antibiotics with activity against extended-spectrum beta-lactamase-producing organisms. Most patients respond to appropriate management within 48 to 72 hours, and those who do not should be evaluated with imaging and repeat cultures while alternative diagnoses are considered. In cases of concurrent urinary tract obstruction, referral for urgent decompression should be pursued. Pregnant patients with pyelonephritis are at significantly elevated risk of severe complications and should be admitted and treated initially with parenteral therapy.

Host and Bacterial Markers that Differ in Children with Cystitis and Pyelonephritis.

OBJECTIVE: To determine whether treatment for urinary tract infections in children could be individualized using biomarkers for acute pyelonephritis. STUDY DESIGN: We enrolled 61 children with febrile urinary tract infections, collected blood and urine samples, and performed a renal scan within 2 weeks of diagnosis to identify those with pyelonephritis. Renal scans were interpreted centrally by 2 experts. We measured inflammatory proteins in blood and urine using LUMINEX or an enzyme-linked immunosorbent assay. We evaluated serum RNA expression using RNA sequencing in a subset of children. Finally, for children with Escherichia coli isolated from urine cultures, we performed a polymerase chain reaction for 4 previously identified virulence genes. RESULTS: Urinary markers that best differentiated pyelonephritis from cystitis included chemokine (C-X-C motif) ligand (CXCL)1, CXCL9, CXCL12, C-C motif chemokine ligand 2, INF γ, and IL-15. Serum procalcitonin was the best serum marker for pyelonephritis. Genes in the interferon-γ pathway were upregulated in serum of children with pyelonephritis. The presence of E coli virulence genes did not correlate with pyelonephritis. CONCLUSIONS: Immune response to pyelonephritis and cystitis differs quantitatively and qualitatively; this may be useful in differentiating these 2 conditions.

Association of mRNA Levels of IL6, MMP-8, GSS in Saliva and Pyelonephritis in Children.

Nowadays, saliva is a subject of growing scientific interest because of its definite advantages as diagnostic medium. The aim of our study was to investigate the diagnostic potential and reliability of messenger RNAs (mRNAs) of selected genes-interleukin-6 (IL-6), matrix metalloproteinase-8 (MMP-8) and glutathione synthetase (GSS)-as salivary markers in children with diagnosed pyelonephritis and to correlate their levels with typical urine para-clinical indicators of the disease. Analysis of the mRNA levels for IL-6, MMP-8 and GSS in 28 children hospitalized with the diagnosis of pyelonephritis was conducted applying the method of quantitative reverse transcription polymerase chain reaction (RT-qPCR). In the study group (n = 28), IL-6 mRNA levels demonstrated 64-fold increase (p < 0.001). MMP-8 and GSS mRNA levels were increased in 12 samples in patients with pyelonephritis 3.27 (p < 0.01) and 1.94 (p < 0.001) times, respectively. We found a strong and significant correlation (p < 0.001) between the investigated mRNA for IL-6 and MMP-8, IL-6 and GSS, MMP-8 and GSS. Moderate degree of correlation was established between IL-6 and the typical para-clinical indicator of leucocytes (0.43, p < 0.05) and between GSS and leucocytes (0.54, p < 0.01). Salivary IL-6, MMP-8 and GSS mRNA levels in combination with urine test analysis could be useful diagnostic tool for the very distributed disorder of pyelonephritis in childhood.

ABILITY TO FORM BIOFILMS BY PYELONEPHRITIS CAUSATIVE AGENTS IN CHILDREN.

The work is dedicated to the study of biofilms formation process by main pyelonephritis causative agents in children in vitro using methods of light, fluorescent and scanning microscopy. To study biofilms formation bacteria were cultivated in liquid substratum on glass in polystyrene Petri dishes d=40mm. The study demonstrated that all isolates formed biofilms. Adhesion of bacteria planktonic forms took place on the first stage, intracellular matrix formation took place on the second stage, and biofilms formation took place on the third stage. During the study of E. coli and Proteus sрр bacteria preparations with the use of scanning and light microscopy ordered bacteria arrangement was seen in the form of separate structures or tiny clusters of bacterial cells united by matrix. During the study of the ability to form P. aeruginosa isolates biofilms with the help of scanning microscopy it was stated that the adhesion of separate bacterial cells occurs by conglomerates formation surrounded by matrix with further biofilms formation. Bacterial cells in the form of dense elongated sticks were seen under the film. P. аeruginosa isolates daily biofilms were stated to have dense structure in the form of gel. Packed biofilms areas with cells clusters with good fluorescence were found with the help of fluorescent microscopy. During daily K.рneumoniae isolates biofilms study by methods of scanning and fluorescent microscopy it was found that K.рneumoniae biofilms were covered with dense matrix and riddled with multiple canals in the form of apertures. During morphological peculiarities study of E. faecalis isolates biofilms formation with the use of scanning and fluorescent microscopy it was found that bacterial cells were densely packed and united by intracellular matrix under which bacteria of spherical shape were seen. Thus biofilms, the nature of which depends on the type of bacteria, are formed on the surface of conglomerates consisting of bacterial cells. Peculiarities of course and appearance of pyelonephritis chronic form and relapses in children is explained by biofilms formation.

[Features of the proteome of the urine in chronic pyelonephritis.]

Clinical observation and examination of 12 patients with chronic pyelonephritis (CPN) were performed. The first group (GI) included patients with exacerbation of the disease. In the comparison group (GII)- the same patients after 1.5-3 months after completion of treatment, without clinical manifestations of exacerbation of CPN. Laboratory signs of acute renal damage were not revealed in all examined patients. Additionally, urine was collected in the afternoon after Breakfast, in the form of a freely separated 2nd fraction and its sample preparation, consisting of the stages: recovery, alkylation, protein deposition and proteolysis using trypsin. The resulting polypeptide mixture was separated by liquid chromatography in three repetitions and analyzed on a system consisting of Agilent 1100 chromatograph and ltq-FT ultra hybrid mass spectrometer. A list of proteins was obtained, indicating the number of peptides by which they were identified, and the parameters of its reliability. Most of the information about the obtained proteins was obtained from UniProt databases. Identified and analyzed 10 proteins that differ significantly in occurrence in the clinical group of patients in the period of exacerbation of PN. The appearance of these proteins in urine in 1patients with exacerbation of chronic PH allows us to consider them as potential biomarkers directly associated with inflammation and damage to the epithelial lining of the renal tubules.

BIOMARKERS OF RENAL INJURY RISK IN CHILDREN WITH PYELONEPHRITIS.

The most common cause of fever in case of anomalies of the urinary system is pyelonephritis (PN). Despite the fact that an intensive search for informative clinical and laboratory markers of PN in children is being conducted in recent years, this problem remains unresolved. Objective - to examine the content of organ-specific enzymes (neutral α-glucosidase (NAG), L-alanine aminopeptidase (AAP), γ-glutamyltranspeptidase (GGTP) in urine and galectin 3 (Gal -3), C-reactive protein (CPR) in blood serum. A prospective, comprehensive clinical and laboratory-instrumental examination was performed in 75 children under the age of 1. The activity of organ-specific enzymes (NAG, AAP, GGTP) in urine and CPR, Gal-3 in the serum of blood were estimated as markers of proximal tubules' damage. The majority (62.99 ± 5.33%) of hospitalized children with febrile temperature and urine changes were diagnosed with PN, which often arose with underlying congenital malformations of the urinary tract. Among children with PN underlaying with VUR, the II and III grades of activity were significantly more frequent. An increase of the level of the enzymes in the urine is observed in the active phase of PN, which correlated with the level of leukocyturia and the level of CRP. During the inactive phase of PN with VUR, the level of enzymes was also higher than the one in children with PN without VUR. High values of Gal-3 were detected in case of underlying VUR, which increased together with increased activity and duration of the inflammatory process in kidneys and correlated with the level of CRP. The Gal-3 can be used for an early diagnosis of fibrotic changes of the renal parenchyma in adolescent children with PN and underlying VUR.

Derivation of decision rules to predict clinically important outcomes in acute flank pain patients.

OBJECTIVE: Routine CT for patients with acute flank pain has not been shown to improve patient outcomes, and it may unnecessarily expose patients to radiation and increased costs. As preliminary steps toward the development of a guideline for selective CT, we sought to determine the prevalence of clinically important outcomes in patients with acute flank pain and derive preliminary decision rules. METHODS: We analyzed data from a randomized trial of CT vs. ultrasonography for patients with acute flank pain from 15 EDs between October 2011 and February 2013. Clinically important outcomes were defined as inpatient admission for ureteral stones and alternative diagnoses. Clinically important stones were defined as stones requiring urologic intervention. We sought to derive highly sensitive decision rules for both outcomes. RESULTS: Of 2759 participants, 236 (8.6%) had a clinically important outcome and 143 (5.2%) had a clinically important stone. A CDR including anemia (hemoglobin <13.2g/dl), WBC count >11000/µl, age>42years, and the absence of CVAT had a sensitivity of 97.9% (95% CI 94.8-99.2%) and specificity of 18.7% (95% 17.2-20.2%) for clinically important outcome. A CDR including hydronephrosis, prior history of stone, and WBC count <8300/µl had a sensitivity of 98.6% (95% CI 94.5-99.7%) and specificity of 26.0% (95% 24.2-27.7%) for clinically important stone. CONCLUSIONS: We determined the prevalence of clinically important outcomes in patients with acute flank pain, and derived preliminary high sensitivity CDRs that predict them. Validation of CDRs with similar test characteristics would require prospective enrollment of 2100 patients.

[Is bacteriological testing of bladder urine informative in acute obstructive pyelo- nephritis?]

The problem of the etiology and pathogenesis of acute obstructive pyelonephritis (OOP) remains one of the challenging issues of modern urology. Etiological agents of pyelonephritis can be both gram-negative and gram-positive opportunistic bacteria mostly belonging to the normal flora in humans. The generally accepted diagnostic work-up involves a bacteriological testing of not pelvic urine, but of bladder urine collected by a transurethral catheter or midstream specimens of urine collected from the patients. The aim of our study was to compare the microbiota of bladder and pelvic urine in patients with OOP. MATERIALS AND METHODS: The study comprised 72 sequentially selected patients (12 men and 60 women) with OOP associated with ureteral stones. Mean age of patients was 53.7+/-0.5 years. All patients underwent bacteriological examination of the bladder urine collected by a transurethral catheter and pelvic urine obtained after relieving stone-related ureteral obstruction. Urinary diversion was performed using j-j stent and PCN in 64 and 8 patients, respectively. Preoperative prophylactic antibiotics were administered routinely. Bacteriological testing of urine was carried out using an extended set (9-10) of culture media. Empirical antibiotic therapy was initiated only after the restoration of urine outflow from the kidney and continued for 5-6 days until the availability of bacteriological testing results. RESULTS: Levels of bacteriuria with Enterobacteria, gram-positive pathogens and NAB in two urine samples did not differ significantly (p>0.05). There was a wide range of bacteriuria from 101 to 106 CFU/ml of most microorganisms except @Proteus spp., S. aureus. In bladder urine, the rates of bacteriuria of more or equal 104 CFU/ml for E. coli, Klebsiella spp. and Proteus spp. were 90.9%, 72.7% and 100.0%, respectively. For the remaining microorganisms, predominant bacteriuria was less or equal 103 CFU/ml. In pelvic urine, the rates of bacteriuria of more or equal 104 CFU/ml for E. coli, Klebsiella spp. and Proteus spp. was 71.8%, 40.0% and 66.7%, respectively. Other uropathogens in the pelvic urine mainly had a bacterial count of less or equal 103 CFU/ml. Only the concentration of Corynebacterium spp. in the pelvic urine significantly (p=0.023) differed from that of the bladder urine. There were no significant differences between microbiota of bladder and pelvic urine depending on duration of OOP except higher rates of Corynebacterium spp. in the bladder urine.

Differentiation of acute pyelonephritis from other febrile states in children using urinary neutrophil gelatinase-associated lipocalin (uNGAL).

BACKGROUND: Acute pyelonephritis is a severe disease which is sometimes difficult to recognize based on clinical symptoms and routinely available diagnostic tests, especially in young children. The aim of this study was to assess the diagnostic value of urinary neutrophil gelatinase-associated lipocalin (uNGAL) as a biomarker of acute pyelonephritis. METHODS: In this case-control study we analyzed 134 children (median age 2.5 years) who were admitted to the Pediatric Clinic of University Hospital Centre Osijek, Croatia. Eighty of them had acute pyelonephritis, while 54 children had febrile state of different etiology including cystitis and they represented the control group. uNGAL, white blood cells, C-reactive protein, urinanalysis, urine culture, kidney ultrasound and a dimercaptosuccinic acid scintigraphic scan were done for each child. uNGAL was measured using chemiluminiscent microparticle immunoassay on ARHITECT i1000SR (Abbott Diagnostics, IL, USA). RESULTS: uNGAL values were significantly higher in children with acute pyelonephritis compared to the control groups (113.6 ng/mL vs. 10.2 ng/mL, p<0.001). A receiver operating characteristic curve comparison was done for tested parameters and encouraging results were obtained for uNGAL (AUC=0.952). A cut-off value of 29.4 ng/mL had 92.5% sensitivity and 90.7% specificity. We showed that uNGAL can also serve in differentiating acute pyelonephritis from cystitis (cut-off 38.5 ng/mL), and for differentiation of cystitis from febrile states with etiology other than urinary tract infection (UTI) (cut-off 20.4 ng/mL). CONCLUSIONS: uNGAL can be a useful diagnostic biomarker in acute pyelonephritis in children, but also in differentiating cystitis from febrile states other than UTI.

[Molecular mechanisms of individual platelet reactivity in hematuria secondary to lithotripsy].

AIM: To investigate the mechanisms of individual platelet reactivity to ADP and adrenaline associated with the variability of hematuria after lithotripsy in patients with chronic obstructive pyelonephritis (COPN). MATERIALS AND METHODS: The study included 41 COPN patients admitted to the Department of Urology for lithotripsy (LT). The contact ultrasonic LT was performed using the Karl Storz Calcuson Ultrasonic Lithotripsy System. Postoperative hematuria was assessed by microscopic red blood cell count. Platelets were separated from the citrated peripheral blood by centrifugation. Platelet aggregation was measured by Chrono-log aggregometer using agonists (ADP, adrenaline) at a concentration of EC50 and EU10. RESULTS: There were three types of platelet functional response to ADP and adrenaline after LT (increased, unchanged and decreased aggregation), but the predominant type of individual response was increased platelet aggregation. Testing 24 hours after LT revealed 7 platelet phenotypes differing in functional activity of 2-adrenoceptor agonist and purine receptors (R2Y1 and R2Y12). Normal purine receptor activity was associated with the ability of platelets to respond to adrenaline by increasing the functional activity aimed at limiting hematuria. Reduced platelet response to ADP after LT reaching the level of hyporesponsiveness may be viewed as a predictor of severe hematuria after surgery. CONCLUSION: Individual platelet reactivity, manifested by the interaction of ADP and adrenaline agonist, determines the effectiveness of the increase in pro-aggregation capacity of platelets in developing postoperative hematuria.

The urine sediment as a biomarker of kidney disease.

The modern era of medicine has ushered in new diagnostic technologies to assist the clinician in evaluating patients with kidney disease. The birth of automated urine analysis technology and centralized laboratory testing has unfortunately made examination of urine sediment by physicians a rare event. At the same time, identifying novel urine biomarkers for kidney disease has become a research priority in nephrology, and the search for the "renal troponin" has progressed at a fast pace. Despite this, urine sediment examination remains a time-honored test that provides a wealth of information about the patient's kidney condition and performs favorably as a urinary biomarker. It alerts the clinician to the presence of kidney disease and provides diagnostic information that often identifies the compartment of kidney injury. In addition, sediment findings may guide therapy and assist in prognostication. As such, it is premature to abandon urine sediment examination. It may be more appropriate to combine urine sediment examination with new candidate biomarkers that enter clinical practice to create a "diagnostic panel" that provides clinicians with a useful battery of diagnostic tests. To accomplish this, we as nephrologists must encourage continued training and maintenance of competency in urine sediment examination.

An endogenous ribonuclease inhibitor regulates the antimicrobial activity of ribonuclease 7 in the human urinary tract.

Recent studies stress the importance of antimicrobial peptides in protecting the urinary tract from infection. Previously, we have shown that ribonuclease 7 (RNase 7) is a potent antimicrobial peptide that has a broad-spectrum antimicrobial activity against uropathogenic bacteria. The urothelium of the lower urinary tract and intercalated cells of the kidney produce RNase 7, but regulation of its antimicrobial activity has not been well defined. Here, we characterize the expression of an endogenous inhibitor, ribonuclease inhibitor (RI), in the urinary tract and evaluate its effect on the antimicrobial activity of RNase 7. Using RNA isolated from non-infected human bladder and kidney tissue, quantitative real-time polymerase chain reaction showed that RNH1, the gene encoding RI, is constitutively expressed throughout the urinary tract. With pyelonephritis, RNH1 expression and RI peptide production significantly decrease. Immunostaining localized RI production to the umbrella cells of the bladder and intercalated cells of the renal collecting tubule. In vitro assays showed that RI bound to RNase 7 and suppressed its antimicrobial activity by blocking its ability to bind the cell wall of uropathogenic bacteria. Thus, these results demonstrate a new immunomodulatory role for RI and identified a unique regulatory pathway that may affect how RNase 7 maintains urinary tract sterility.

Predictive value of urinary and serum biomarkers in young children with febrile urinary tract infections.

BACKGROUND: Early predictive biomarkers for the diagnosis and management of febrile urinary tract infections (UTIs) can be valuable diagnostic tools in children. METHODS: The study cohort comprised 73 pediatric patients with febrile UTIs [46 with acute pyelonephritis (APN) and 27 with lower UTIs] and 56 healthy children. Urine neutrophil gelatinase-associated lipocalin (uNGAL) and kidney injury molecule-1 (uKIM-1) levels and serum cystatin C (sCysC) levels were measured. RESULTS: The uNGAL/creatinine (Cr) and uKIM-1/Cr levels were higher in the UTI group than in the controls (P < 0.05). uNGAL/Cr and sCysC levels were higher in patients with APN than in those with lower UTIs (P < 0.05). uNGAL/Cr levels in both the APN and UTI groups decreased following the administration of antibiotics compared to those before treatment (P < 0.05). The uNGAL/Cr level was correlated with serum levels of white blood cells, C-reactive protein, CysC and with uKIM-1/Cr (P < 0.05). uKIM-1/Cr was also correlated with sCysC (P < 0.05). Receiver operating curve analyses showed good diagnostic profiles of uNGAL/Cr and uKIM-1/Cr for identifying UTIs [area under the curve (AUC) 0.9 and 0.66, respectively) and of uNGAL/Cr and sCysC for predicting APN (AUC 0.78 and 0.72, respectively). CONCLUSIONS: Our results suggest that uNGAL, uKIM-1 and sCysC levels may be useful for predicting and managing febrile UTIs in children.

Usefulness of serum amyloid A for the diagnosis of pyelonephritis in cats: A prospective evaluation.

BACKGROUND: The diagnosis of pyelonephritis in cats is challenging and development of a noninvasive and accurate biomarker is needed. HYPOTHESES: Serum amyloid A (SAA) is increased in cats with pyelonephritis, but not in cats with other urinary tract diseases. ANIMALS: A cohort of 125 cats (149 observations). METHODS: This was a prospective study. Group 1 included cats with a diagnosis of pyelonephritis either confirmed by bacterial culture of pelvic urine (Group 1a) or presumed (1b). Group 2 included cats for which pyelonephritis was ruled out (with certainty: Group 2a or judged unlikely: Group 2b). SAA concentration was compared between groups, and accuracy of SAA for the diagnosis of pyelonephritis was calculated using a Receiver Operating Characteristic (ROC) curve analysis. RESULTS: Median SAA concentration was significantly higher in Group 1a (86.8 mg/L [73.3; 161.5]; n = 8) than in Group 2a (4 mg/L [1.8; 5.6], n = 19; P < .001) and in Group 2b (5.4 mg/L [3.1; 9.7], n = 113; P < .001). It was also significantly higher in Group 1b (98.8 mg/L [83.1; 147.3]; n = 9) than in Group 2b (P < .001) and Group 2a (P < .001). Optimal diagnostic cut-off for SAA concentration was 51.3 mg/L. yielding a sensitivity of 88% (95% confidence interval: [64%; 99%]) and a specificity of 94% (95% confidence interval: [88%; 97%]). CONCLUSIONS AND CLINICAL IMPORTANCE: Measurement of SAA could be used to rule out pyelonephritis in the case of low suspicion of the disease. Increased SAA concentration is suggestive of pyelonephritis despite a lack of specificity.

Ribonuclease 7, an antimicrobial peptide upregulated during infection, contributes to microbial defense of the human urinary tract.

The mechanisms that maintain sterility in the urinary tract are incompletely understood; however, recent studies stress the importance of antimicrobial peptides in protecting the urinary tract from infection. Ribonuclease 7 (RNase 7), a potent antimicrobial peptide contributing to urinary tract sterility, is expressed by intercalated cells in the renal collecting tubules and is present in the urine at levels sufficient to kill bacteria at baseline. Here, we characterize the expression and function of RNase 7 in the human urinary tract during infection. Both quantitative real-time PCR and enzyme-linked immunosorbant assays demonstrated increases in RNASE7 expression in the kidney along with kidney and urinary RNase 7 peptide concentrations with infection. While immunostaining localized RNase 7 production to the intercalated cells of the collecting tubule during sterility, its expression during pyelonephritis was found to increase throughout the nephron but not in glomeruli or the interstitium. Recombinant RNase 7 exhibited antimicrobial activity against uropathogens at low micromolar concentrations by disrupting the microbial membrane as determined by atomic force microscopy. Thus, RNase 7 expression is increased in the urinary tract with infection and has antibacterial activity against uropathogens at micromolar concentrations.

Urinary concentration of cytokines in children with acute pyelonephritis.

Urinary tract infection (UTI) is a common bacterial infection among infants and children. Predicting which children with upper UTI will develop long-term sequelae remains difficult. We aimed at evaluating the predictive value of urine concentrations of interleukin-6 (UIL-6) and interleukin-8 (UIL-8) in subsequent renal scarring. In the current observational prospective study, urine samples for UIL-6 and UIL-8 were obtained from two groups: 31 children with first episode of febrile UTI and 22 febrile children of other origin. UIL-6 and UIL-8 were increased in children with febrile UTI, compared to children with fever of other origin [median and range (picograms per milliliter): (1) UIL-6, 74.46 (0-168) vs. 10.51 (0-47.50), respectively, p = 0.0001; (2) UIL-8, 2,660.38 (0-13,801) vs. 0, respectively, p = 0.0001]. Renal scarring was found in 5/31 (16 %) children with acute pyelonephritis. Initial median UIL-8 values were significantly higher in children with later renal scarring than in those without renal scarring [median and range (picograms per milliliter): 6,163 (2,021-13,801) vs. 1,490.5 (0-5,737), respectively, p = 0.018]. In conclusion, UIL-8 might serve as a predictive biomarker for renal scarring after an acute episode of pyelonephritis. Since UIL-8 emerges as a renal-specific diagnostic and prognostic marker, it may be suitable as a selective screening tool for children with febrile UTI.

[Formation of microbial biofilms in causative agents of acute and chronic pyelonephritis].

AIM: Study the intensity of formation of microbial biofilms by Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus strains isolated during various forms of pyelonephritis. MATERIALS AND METHODS: 150 clinical isolates of microorganisms isolated from urine ofpatientswith acute and chronic pyelonephritiswere included into the study. Determination of intensity of film-formation was carried out by staining of the formed biofilms by crystal violet with consequent extraction of the dye and measurement of its concentration in washout solution. RESULTS: Among causative agents ofpyelonephritis P. aeruginosa isolates had the maximum film-forming ability. The intensity of biofilm formation of these isolates was 2-3 time higher than staphylococcus and enterobacteria strains. Strains isolated from patients with chronic pyelonephritis by ability to form biofilms significantly surpassed strains isolated from acute pyelonephritis patients. A higher ability to form microbial biofilms for microorganisms--causative agents of pyelonephritis progressing against the background ofurolithiasis was noted. CONCLUSION: The ability to form biofilms is determined by both causative agent species and character of the infectious process in which this microorganism participates. Intensive formation of biofilms by E. coli, P. aeruginosa, K. pneumoniae, S. aureus clinical isolates may be an important factor of chronization of urinary tract infections.