Acute pyelonephritis in children

Kidney involvement during the course of febrile urinary tract infection

Febrile urinary tract infections (fUTIs) are among the most common severe infections in the pediatric population, posing a significant risk to kidney health. The pathophysiology of fUTIs involves the direct bacterial invasion of kidney tissue, which triggers an inflammatory response. While this response is effective in eradicating the infection, it can also cause substantial kidney damage at multiple levels. In this review, we explore the various forms of kidney involvement in fUTIs, along with their clinical, radiological, and biochemical presentations. We also discuss the implications of these events for the long-term prognosis of kidney function. Understanding these manifestations can assist clinicians in making prompt diagnoses and initiating appropriate treatment to minimize complications such as sepsis, kidney scarring, and long-term kidney damage.

Urinary Tract Infections in Children: Changing Trends in Etiology and Local Resistance Patterns over a Three-Year Period

INTRODUCTION

Urinary tract infections are common in pediatrics. Knowledge of local resistance patterns is crucial to guide empirical antibiotic therapy. We aimed to review the pathogens implicated in urinary tract infections, local resistance patterns, and the impact of switching first-line empirical antibiotic regimens.

METHODS

We conducted a cross-sectional study including pediatric patients performing urine cultures in a hospital in northern Portugal over two periods: 2019 (group 1) and 2022 (group 2). Between time periods, an internal guideline was implemented recommending cefuroxime as the first-line choice for empirical treatment of urinary tract infections, according to local resistance patterns. Uropathogens, empirical antibiotic choices and resistance patterns were compared among groups.

RESULTS

The final sample included 402 cases of urinary tract infections in group 1 and 398 in group 2. Escherichia coli was the most common uropathogen (79.4 - 83.3%), followed by Proteus mirabilis and Klebsiella spp. The most common empirical antibiotic in group 1 was amoxicillin-clavulanate (A-C), as opposed to cefuroxime in group 2 (p < 0.001). The most common resistance was to ampicillin (39.3% - 39.7%). Resistance to A-C slightly decreased (33.1% vs 27.4%, p = 0.079), while resistance to cefuroxime (4.7% vs 3.3%, p = 0.292) and trimethoprim-sulfamethoxazole (TMP-SMX) remained similar (15.2% vs 14.1%, p = 0.659). Resistances to nitrofurantoin (9.0% vs 0.3%, p < 0.001) and fosfomycin (1.7% vs 0.3%, p < 0.036) significantly decreased from group 1 to group 2.

CONCLUSION

E.coli remains the predominant pathogen in pediatric urinary tract infections. Resistance to A-C in our sample was high (33.1%). The switch from A-C to cefuroxime as first-line agent resulted in a decreasing trend in A-C resistance, while cefuroxime resistance remained low and even slightly lower.

Rate and yield of imaging for acute pyelonephritis in the emergency department: A retrospective cohort study

OBJECTIVES

The role of imaging in acute pyelonephritis (APN) in the ED is poorly understood, with variability among clinical guidelines for when patients should be imaged, and the modality of imaging. The objective of this study was to identify the proportion of patients with APN being imaged, the proportion abnormal findings, and the association between abnormal imaging and discharge disposition.

METHODS

A single-centre retrospective review of patients with a discharge diagnosis of APN at an adult tertiary referral hospital over a 5-year period (2018-2022) was conducted. The proportion of patients with APN investigated with imaging, and abnormalities on imaging were reported. Logistic regression analyses were performed to assess whether imaging was associated with change in disposition from the ED.

RESULTS

There were 778 patients included for analysis. Among these, 210 (27%) were investigated with ultrasound (US) and/or computed tomography (CT) in the ED. Of the 214 imaging reports available, 112 (52%) were abnormal. Imaging was associated with hospital ward admission (adjusted odds ratio [aOR] 5.28; 95% confidence interval [CI] 3.35-8.31) as was abnormal imaging (aOR 4.51; 95% CI 2.62-7.75). Other variables associated with hospital ward admission were higher temperature and heart rate, higher C-reactive protein levels and poorer renal function.

CONCLUSIONS

Among patients with APN, abnormalities on imaging were common and both imaging and abnormalities on imaging were associated with hospital ward admission. This suggests that there is possible utility of early and routine imaging for patients with APN to allow clinicians to efficiently make decisions about patient disposition.

Association between hyponatremia and disease severity in pediatric urinary tract infections

BACKGROUND

Acute urinary tract infection (UTI) is a common disease in pediatrics, with around 8% of girls and 2% of boys experiencing a UTI by age 7y/o. UTIs can range from asymptomatic bacteriuria to acute pyelonephritis (APN) in severe cases involving renal parenchymal infection. UTI patients admitted to the pediatric ward usually have more severe clinical presentation, compared to those treated in the outpatient settings. Therefore, it will be helpful to have markers that predict the severity of the disease and the likelihood of having APN.

METHODS

We performed a retrospective review on all pediatric UTI/APN patients treated in the inpatient setting at a Medical Center from October 2012 to September 2022. Patients were assigned to the "hyponatremia" or "eunatremia" group according to their serum sodium concentrations. Detailed information, including renal echo, blood, and urine test results, were collected for the analysis of multivariable logistic regression model.

RESULTS

The study included 344 patients, of which 99 (28.8%) had hyponatremia, and 245 (71.2%) had normal serum sodium levels. The hyponatremia group had higher APN frequency, renal echo abnormality, and higher CRP level. In multivariable analysis, hyponatremia was independently associated with increased serum glucose (OR: 1.01, 95% CI: 1.00-1.03, p = 0.0365) and CRP levels (OR: 1.00, 95% CI: 1.00-1.01, p = 0.0417), without a significant increase in APN frequency as the final diagnosis.

CONCLUSIONS

Our findings suggest that hyponatremia in pediatric UTI patients may indicate a more severe disease, such as APNs, higher CRP levels, or renal echo abnormalities. The complex mechanisms underlying hyponatremia and its predictive value for disease severity warrant further investigation.

Label-free investigation of infected acute pyelonephritis tissue by FTIR microspectroscopy with unsupervised and supervised analytical methods

Acute pyelonephritis (AP) is a severe urinary tract infection (UTI) syndrome with a large population of patients worldwide. Current approaches to confirming AP are limited to urinalysis, radiological imaging methods and histological assessment. Fourier transform infrared (FTIR) microspectroscopy is a promising label-free modality that can offer information about both morphological and molecular pathologic alterations from biological tissues. Here, FTIR microspectroscopy serves to investigate renal biological histology of a rat model with AP and classify normal cortex, normal medulla and infected acute pyelonephritis tissues. The spectra were experimentally collected by FTIR with an infrared Globar source through raster scanning procedure. Unsupervised analysis methods, including integrating, clustering and principal component analysis (PCA) were performed on such spectra data to form infrared histological maps of entire kidney section. In comparison to Hematoxylin & Eosin-stained results of the adjacent tissue sections, these infrared maps were proved to enable the differentiation of the renal tissue types. The results of both integration and clustering indicated that the concentration of amide II decreases in the infected acute pyelonephritis tissues, with an increased presence of nucleic acids and lipids. By means of PCA, the infected tissue was linearly separated from normal ones by plotting confident ellipses with the score values of the first and second principal components. Moreover, supervised analysis was performed based on the supported vector machines (SVM). Normal cortex, normal medulla and infected acute pyelonephritis tissues were classified by SVM models with the best accuracy of 96.11% in testing dataset. In addition, these analytical methods were further employed on synchrotron-based FTIR spectra data and successfully form high-resolution infrared histological maps of glomerulus and necrotic cell mass. This work demonstrates that FTIR microspectroscopy will be a powerful manner to investigate AP tissue and differentiate infected tissue from normal tissue in a renal infected model system.

Plasma and Urinary Neutrophil Gelatinase-Associated Lipocalin as Predictors of Renal Parenchymal Involvement in Children with Febrile Urinary Tract Infection: A Pilot Study

BACKGROUND

Urinary tract infections (UTIs) are very common bacterial infections in children. Early detection of renal parenchymal involvement in this setting can help clinicians make more effective treatment choices. The aim of this pilot study was to assess the ability of plasma and urinary neutrophil gelatinase-associated lipocalin (pNGAL and uNGAL) levels, measured using an automated system, to accurately predict renal parenchymal involvement in children with febrile UTIs.

METHODS

This prospective single-center study included 28 children aged ≥ 4 years with a first episode of febrile UTIs. All patients underwent magnetic resonance imaging. pNGAL, uNGAL, procalcitonin, C-reactive protein (CRP), and white blood cells were measured before antibiotic therapy.

RESULTS

The receiver operating characteristic (ROC) area under the curve for predicting acute pyelonephritis was 0.6 for pNGAL, 0.8 for CRP, 0.4 for PCT, and 0.4 for uNGAL. The ROC analyses showed an optimal cutoff of 141.0 ng/mL for pNGAL (sensitivity, 54.2%; specificity, 75.0%; positive predictive value, 92.9%; and negative predictive value, 21.4%).

CONCLUSION

pNGAL and uNGAL did not effectively aid the early prediction of renal parenchymal involvement in children ≥ 4 years with febrile UTIs. The novelties of this study were the use of MRI as the gold standard and an automated biochemical method to measure NGAL.

Decreased incidence of urinary tract infections in febrile infants aged ≤60 days during COVID-19 pandemic

AIM

To investigate the incidence rate of urinary tract infections (UTIs) among febrile infants aged ≤60 days before, during, and after the COVID-19 pandemic.

METHODS

We conducted a retrospective study in 2 Swedish paediatric emergency departments between 2014 and 2022. We included full-term infants aged ≤60 days with fever without source. We calculated the annual incidence rate of UTI per 1000 births.

RESULTS

We included 1589 full-term infants with fever without source. In 2020, 89 infants were evaluated in the emergency department versus 203-259 in 2017-2019. In 2020, the incidence rate of UTI was 1.43 per 1000 births/year versus 2.18-2.37 in 2017-2019. The median age, sex, fever duration, and urine testing were similar between the years 2017 and 2020.

CONCLUSION

The number of febrile infants who presented to the paediatric emergency department and the incidence rate of UTIs decreased in 2020. This decrease might imply a systematic misdiagnosis of UTIs in infants with febrile viral infections. A more selective urine testing approach for febrile, previously healthy, infants should be considered to mitigate UTI misdiagnosis and its potential harmful effects.

Acute kidney injury in children hospitalised for febrile urinary tract infection

AIM

To determine (i) prevalence and the risk factors for acute kidney injury (AKI) in children hospitalised for febrile urinary tract infection (fUTI) and (ii) role of AKI as indicator of an underlying VUR. AKI, in fact, is favoured by a reduced nephron mass, often associated to VUR.

METHODS

This retrospective Italian multicentre study enrolled children aged 18 years or younger (median age = 0.5 years) discharged with a primary diagnosis of fUTI. AKI was defined using Kidney Disease/Improving Global Outcomes serum creatinine criteria.

RESULTS

Of 849 children hospitalised for fUTI (44.2% females, median age 0.5 years; IQR = 1.8), 124 (14.6%) developed AKI. AKI prevalence rose to 30% in the presence of underlying congenital anomalies of the kidney and urinary tract (CAKUT). The strongest AKI predictors were presence of CAKUT (OR = 7.5; 95%CI: 3.8-15.2; p = 9.4e-09) and neutrophils levels (OR = 1.13; 95%CI: 1.08-1.2; p = 6.8e-07). At multiple logistic regression analysis, AKI during fUTI episode was a significant indicator of VUR (OR = 3.4; 95%CI: 1.7-6.9; p = 0.001) despite correction for the diagnostic covariates usually used to assess the risk of VUR after the first fUTI episode. Moreover, AKI showed the best positive likelihood ratio, positive predictive value, negative predictive value and specificity for VUR.

CONCLUSION

AKI occurs in 14.6% of children hospitalised for fUTI and is a significant indicator of VUR.

Enhancing clinical decision-making: Sysmex UF-5000 as a screening tool for bacterial urinary tract infection in children

BACKGROUND

A rapid screening test for urinary tract infections (UTIs) in children is needed to avoid unnecessary cultures and provide prompt reports to make appropriate clinical decisions. We have evaluated for the first time the performance of the Sysmex UF-5000 flow cytometer as a screening tool for UTIs in children.

METHODS

This study included 4445 pediatric patients, with urinary sediment and urine culture data collected from January 2020 to September 2023. The Sysmex UF-5000 analyzer was utilized to measure urine white blood cell (WBC) and bacteria (BACT), with the findings being compared to the culture results.

RESULTS

At ≥ 104 colony-forming unit (CFU)/mL, 513 samples were culture-positive (400 samples presented 104-105 CFU/mL, and 113 demonstrated ≥ 105 CFU/mL bacterial growth). Optimal indicators for positive cultures were BACT counts of 92.2/μL (AUC: 0.944) and WBC counts of 40.8/μL (AUC:0.863). False negative rate were 0.9% when using a 7.8 bacteria/μL cut-off and avoiding unnecessary cultures in 28.1%. The UF-5000 has a higher consistency rate for Gram-negative (GN) bacteria (90.3%) than Gram-positive (GP) bacteria (86.8%). For samples with 105 CFU/mL, UF-5000's Bacteria -Information flags showed superior concordance for samples with 104-105 CFU/mL bacteria.

CONCLUSIONS

Screening pediatric urine cultures with the UF-5000 showed potential application value in identifying negative cultures and significant bacterial growth, although performance may vary depending on the study population. Furthermore, detecting Gram typing aids in guiding early clinical empirical medication, particularly for UTIs caused by GN bacteria.

Evidence-based clinical practice guideline for management of urinary tract infection and primary vesicoureteric reflux

We present updated, evidence-based clinical practice guidelines from the Indian Society of Pediatric Nephrology (ISPN) for the management of urinary tract infection (UTI) and primary vesicoureteric reflux (VUR) in children. These guidelines conform to international standards; Institute of Medicine and AGREE checklists were used to ensure transparency, rigor, and thoroughness in the guideline development. In view of the robust methodology, these guidelines are applicable globally for the management of UTI and VUR. Seventeen recommendations and 18 clinical practice points have been formulated. Some of the key recommendations and practice points are as follows. Urine culture with > 104 colony forming units/mL is considered significant for the diagnosis of UTI in an infant if the clinical suspicion is strong. Urine leukocyte esterase and nitrite can be used as an alternative screening test to urine microscopy in a child with suspected UTI. Acute pyelonephritis can be treated with oral antibiotics in a non-toxic infant for 7-10 days. An acute-phase DMSA scan is not recommended in the evaluation of UTI. Micturating cystourethrography (MCU) is indicated in children with recurrent UTI, abnormal kidney ultrasound, and in patients below 2 years of age with non-E. coli UTI. Dimercaptosuccinic acid scan (DMSA scan) is indicated only in children with recurrent UTI and high-grade (3-5) VUR. Antibiotic prophylaxis is not indicated in children with a normal urinary tract after UTI. Prophylaxis is recommended to prevent UTI in children with bladder bowel dysfunction (BBD) and those with high-grade VUR. In children with VUR, prophylaxis should be stopped if the child is toilet trained, free of BBD, and has not had a UTI in the last 1 year. Surgical intervention in high-grade VUR can be considered for parental preference over antibiotic prophylaxis or in children developing recurrent breakthrough febrile UTIs on antibiotic prophylaxis.

Phenotypic characterization of ESBL-producing urinary isolates of E. coli and Klebsiella spp. in a tertiary care children's hospital in Nepal

BACKGROUND

The production of extended-spectrum beta-lactamases (ESBLs) among uropathogens, particularly E. coli and Klebsiella spp., poses a severe public health concern. This study explored the epidemiology of ESBL-producing E. coli and Klebsiella spp. isolated from urine samples obtained at a tertiary care children's hospital in Nepal.

METHODS

A cross-sectional study was conducted from August 2016 to February 2017. A total of 745 clean catch urine samples were obtained from pediatric patients under the age of 13 and subjected to semiquantitative culture. E. coli and Klebsiella spp. were identified using standard laboratory protocols. Antibiotic susceptibility testing was performed using the Kirby-Bauer disc diffusion method, and ESBL producers were phenotypically identified using the combined disk method.

RESULTS

Among the bacterial isolates, E. coli predominated, accounting for 139 (81.8%) positive cases. Notably, E. coli showed high susceptibility to nitrofurantoin, with 117 (84.2%) isolates being susceptible. Meanwhile, K. pneumoniae showed high susceptibility to gentamicin, with 21 (91.3%) isolates being susceptible. Of the 163 isolates of E. coli and Klebsiella spp., 62 (38.0%) were identified as multidrug-resistant (MDR), with 42 (25.8%) confirmed as phenotypic ESBL producers. Remarkably, all 41 (100%) ESBL-producing E. coli isolates were susceptible to imipenem.

CONCLUSIONS

The prevalence of ESBL producers among E. coli and K. pneumoniae isolates from pediatric patients underscores the importance of antimicrobial stewardship. Nitrofurantoin and gentamicin emerge as effective empirical treatment choices against these pathogens in children. However, the high rates of multidrug resistance and ESBL production highlight the necessity for routine surveillance, and early detection strategies to manage such infections effectively.

Bacteriuria in Paediatric Oncology Patients: Clinical Features, Distribution and Antimicrobial Susceptibility of Bacterial Pathogens at University Hospital Centre Zagreb, Croatia over a 4-Year Period

Bacteriuria in paediatric oncology patients have not been well studied. This retrospective study analysed clinical features, distribution and antimicrobial susceptibility of bacterial pathogens cultured from urine in paediatric oncology patients over a 4-year period (2019-2022). A total of 143 episodes of bacteriuria were documented in 74 patients. Neutropenia was present in 17.5% (25/143), symptoms in 25.9% (37/143) and urinary catheter in 7.0% (10/143) episodes. Symptomatic bacteriuria episodes were statistically significantly more frequent in patients with neutropenia (p = 0.0232). The most common bacterial pathogens were Escherichia coli (n = 49; 32.2%), Klebsiella spp. (n = 34; 22.4%), Pseudomonas aeruginosa (n = 22; 14.5%) and Enterococcus spp. (n = 21; 13.8%). Extended-spectrum β-lactamases-producing (ESBL) Enterobacterales were found in 11 episodes (11/143; 7.7%) with the highest proportion among Klebsiella pneumoniae isolates (n = 7/34; 20.6%). No carbapenem-resistant Enterobacterales, multidrug-resistant P. aeruginosa or vancomycin-resistant Enterococcus spp. were found. The most important novelties are demonstrating P. aeruginosa as one of the prominent bacteriuria pathogens in this patient population, presence of ESBL isolates and carbapenem-resistant P. aeruginosa later during hospitalization highlights the need for appropriate antimicrobial treatment. However, because of the small number of symptomatic patients, further studies are needed to clarify the importance of including urine culture in the diagnostic process in patients with febrile neutropenia.

Conflicting views of physicians and surgeons concerning pediatric urinary tract infection: a comparative review

BACKGROUND

A first febrile urinary tract infection (UTI) is a common condition in children, and pathways of management have evolved over time.

OBJECTIVE

To determine the extent to which pediatricians and surgeons differ in their investigation and management of a first febrile UTI, and to evaluate the justifications for any divergence of approach.

MATERIALS AND METHODS

A literature search was conducted for papers addressing investigation and/or management following a first febrile UTI in children published between 2011 and 2021. Searches were conducted on Medline, Embase, and the Cochrane Controlled Trials Register. To be eligible for inclusion, a paper was required to provide recommendations on one or more of the following: ultrasound (US) and voiding cystourethrogram (VCUG), the need for continuous antibiotic prophylaxis and surgery when vesicoureteral reflux (VUR) was detected. The authorship required at least one pediatrician or surgeon. Authorship was categorized as medical, surgical, or combined.

RESULTS

Pediatricians advocated less imaging and intervention and were more inclined to adopt a "watchful-waiting" approach, confident that any significant abnormality, grades IV-V VUR in particular, should be detected following a second febrile UTI. In contrast, surgeons were more likely to recommend imaging to detect VUR (p<0.00001), and antibiotic prophylaxis (p<0.001) and/or surgical correction (p=0.004) if it was detected, concerned that any delay in diagnosis and treatment could place the child at risk of kidney damage. Papers with combined authorship displayed intermediate results.

CONCLUSION

There are two distinct directions in the literature regarding the investigation of an uncomplicated first febrile UTI in a child. In general, when presented with a first febrile UTI in a child, physicians recommend fewer investigations and less treatment, in contrast to surgeons who advocate extensive investigation and aggressive intervention in the event that imaging detects an abnormality. This has the potential to confuse the carers of affected children.

Uropathogen and host responses in pyelonephritis

Urinary tract infections (UTIs) are among the most common bacterial infections seen in clinical practice. The ascent of UTI-causing pathogens to the kidneys results in pyelonephritis, which can trigger kidney injury, scarring and ultimately impair kidney function. Despite sizable efforts to understand how infections develop or are cleared in the bladder, our appreciation of the mechanisms by which infections develop, progress or are eradicated in the kidney is limited. The identification of virulence factors that are produced by uropathogenic Escherichia coli to promote pyelonephritis have begun to fill this knowledge gap, as have insights into the mechanisms by which kidney tubular epithelial cells oppose uropathogenic E. coli infection to prevent or eradicate UTIs. Emerging data also illustrate how specific cellular immune responses eradicate infection whereas other immune cell populations promote kidney injury. Insights into the mechanisms by which uropathogenic E. coli circumvent host immune defences or antibiotic therapy to cause pyelonephritis is paramount to the development of new prevention and treatment strategies to mitigate pyelonephritis and its associated complications.

Antibiotic Prophylaxis in Infants with Grade III, IV, or V Vesicoureteral Reflux

BACKGROUND

The efficacy of continuous antibiotic prophylaxis in preventing urinary tract infection (UTI) in infants with grade III, IV, or V vesicoureteral reflux is controversial.

METHODS

In this investigator-initiated, randomized, open-label trial performed in 39 European centers, we randomly assigned infants 1 to 5 months of age with grade III, IV, or V vesicoureteral reflux and no previous UTIs to receive continuous antibiotic prophylaxis (prophylaxis group) or no treatment (untreated group) for 24 months. The primary outcome was the occurrence of the first UTI during the trial period. Secondary outcomes included new kidney scarring and the estimated glomerular filtration rate (GFR) at 24 months.

RESULTS

A total of 292 participants underwent randomization (146 per group). Approximately 75% of the participants were male; the median age was 3 months, and 235 participants (80.5%) had grade IV or V vesicoureteral reflux. In the intention-to-treat analysis, a first UTI occurred in 31 participants (21.2%) in the prophylaxis group and in 52 participants (35.6%) in the untreated group (hazard ratio, 0.55; 95% confidence interval [CI], 0.35 to 0.86; P = 0.008); the number needed to treat for 2 years to prevent one UTI was 7 children (95% CI, 4 to 29). Among untreated participants, 64.4% had no UTI during the trial. The incidence of new kidney scars and the estimated GFR at 24 months did not differ substantially between the two groups. Pseudomonas species, other non-Escherichia coli organisms, and antibiotic resistance were more common in UTI isolates obtained from participants in the prophylaxis group than in isolates obtained from those in the untreated group. Serious adverse events were similar in the two groups.

CONCLUSIONS

In infants with grade III, IV, or V vesicoureteral reflux and no previous UTIs, continuous antibiotic prophylaxis provided a small but significant benefit in preventing a first UTI despite an increased occurrence of non-E. coli organisms and antibiotic resistance. (Funded by the Italian Ministry of Health and others; PREDICT ClinicalTrials.gov number, NCT02021006; EudraCT number, 2013-000309-21.).

Multiple pneumatoceles and lung abscesses caused by early-onset E. coli sepsis in a preterm neonate

Early-onset sepsis (EOS) is a serious and fatal illness in neonates, Group B Streptococcus and Escherichia coli are major causative pathogens. We report a case of EOS and pneumonia caused by E. coli in a preterm neonate with multiple pneumatoceles and lung abscesses. A male neonate weighing 1670g was delivered at 33 6/7 weeks' gestation by a mother with clinical chorioamnionitis. He showed respiratory distress soon after birth and developed septic shock. He was intubated and mechanical ventilation was started. E.coli was detected in blood culture obtained from both the patient and his mother. He developed multiple pneumatoceles and lung abscesses. Surgical drainage was complicated, cefotaxime was thus continued until day 74. Pneumatoceles and lung abscesses are complications of neonatal pneumonia, rarely reported by E. coli. Multiple lung abscesses in our patient are distinct from single abscesses in previous case studies of neonatal lung abscesses. We speculate that bacteremia along with pneumatoceles led to multiple lung abscesses in our patient. These complications require long-term antibiotic therapy, to minimize morbidity and mortality, and should thus be considered when managing EOS caused by E. coli.

Incidence of renal scarring on technetium-99 m dimercaptosuccinic acid renal scintigraphy after acute pyelonephritis, acute focal bacterial nephritis, and renal abscess

OBJECTIVE

To evaluate the association between the incidence of renal scarring on technetium-99 m dimercaptosuccinic acid (DMSA) renal scintigraphy and the severity of renal parenchymal infections, such as acute pyelonephritis (APN), acute focal bacterial nephritis (AFBN), and renal abscess, based on computed tomography (CT) diagnosis.

METHODS

Sixty-one children with renal parenchymal infections were included and classified into two groups: those with (renal scarring group) and without renal scarring (non-renal scarring group) on chronic-phase DMSA renal scintigraphy. The severity of renal parenchymal infection was classified into three grades using CT: APN, AFBN, and renal abscess as grades 1, 2, and 3, respectively. The severity of renal parenchymal infection, vesicoureteral reflux (VUR) grade, and intrarenal reflux occurrence during voiding cystourethrography (VCUG) were evaluated between the renal and non-renal scarring groups. Fisher's exact test and Mann-Whitney U test were used for statistical analysis.

RESULTS

Renal scars were detected in 28 (45.9%) of the 61 patients. We found that 2/9 (22.2%), 18/41 (43.9%), and 8/11 (72.7%) patients with APN (grade 1), AFBN (grade 2), and renal abscess (grade 3) had renal scarring, respectively. There was a significant difference in the grade of severity of renal parenchymal infection between the renal (median = 2 [interquartile range, 2-3]) and non-renal (median = 2 [interquartile range, 2-2]) scarring groups (p = 0.023). There was a significant difference in the grade of VUR between the renal (median = 3 [interquartile range, 0-4]) and non-renal (median = 0 [interquartile range, 0-2]) scarring groups (p = 0.004). No significant difference in intrarenal reflux occurrence was observed between the renal (present/absent: 3/25) and non-renal (present/absent: 0/29) scarring groups (p = 0.112).

CONCLUSION

Our results showed that pediatric patients with renal scarring on chronic-phase DMSA renal scintigraphy tended to have a more severe renal infection.

The genotypic and phenotypic characteristics contributing to high virulence and antibiotics resistance in Escherichia coli O25-B2-ST131 in comparison to non- O25-B2-ST131

BACKGROUND

Escherichia coli serogroup O25b-sequence type 131 (E. coli O25-B2-ST131) is considered as multidrug-resistant and hypervirulent organism. There is lack of data about involvement of this pathogen in the children's infection. In this study, the prevalence, and clonality, virulence capacity, and antibiotic resistance phenotype and genotype of E. coli O25-B2-ST131 compared with non-O25-B2-ST131 isolates were investigated in children with urinary tract infection in Tehran, Iran.

METHODS

The E. coli isolates from urine samples were identified using conventional microbiological methods. Characterization of E. coli O25-B2-ST131 clone, antibiotic susceptibility, biofilm formation, ESBLs phenotype and genotype, serum resistance, hemolysis, hydrophobicity, and formation of curli fimbriae were done using conventional microbiological and molecular methods. Clonality of the isolates was done by rep-PCR typing.

RESULTS

Among 120 E. coli isolates, the highest and lowest antibiotic resistance was detected against ampicillin (92, 76.6%) and imipenem 5, (4.1%), respectively. Sixty-eight (56.6%) isolates were ESBL-producing and 58 (48.3%) isolates were considered as multi-drug resistance (MDR). The prevalence of ESBL-producing and MDR isolates in O25-B2-ST131 strains was higher compared with the non-O25-B2-ST131 strains (p value < 0.05). O25-B2-ST131 strains showed significant correlation with serum resistance and biofilm formation. Amongst the resistance and virulence genes, the prevalence of iucD, kpsMTII, cnf1, vat, bla_CTX-M-15, and bla_SHV were significantly higher among O25-B2-ST131 isolates in comparison with non-O25-B2-ST131 isolates (p value < 0.05). Considering a ≥ 80% homology cut-off, fifteen different clusters of the isolates were shown with the same rep-PCR pattern.

CONCLUSIONS

Our results confirmed the involvement of MDR-ESBLs producing E. coli strain O25-B2-ST131 in the occurrence of UTIs among children. Source tracking and control measures seem to be necessary for containment of the spread of hypervirulent and resistance variants in children.

Epidemiology and Risk Factors of UTIs in Children-A Single-Center Observation

Urinary tract infections (UTIs) are one of childhood’s most common bacterial infections. The study aimed to determine the clinical symptoms, laboratory tests, risk factors, and etiology of different UTIs in children admitted to pediatric hospitals for three years. Methods: Patients with positive urine cultures diagnosed with acute pyelonephritis (APN) or cystitis (CYS) were analyzed for clinical symptoms, laboratory tests, risk factors, and etiology, depending on their age and sex. Results: We studied 948 children with UTIs (531 girls and 417 boys), with a median age of 12 (IQR 5−48 months). A total of 789 children had clinical symptoms; the main symptom was fever (63.4% of patients). Specific symptoms of UTIs were presented only in 16.3% of patients. Children with APN had shown significantly more frequent loss of appetite, vomiting, lethargy, seizures, and less frequent dysuria and haematuria than children with CYS. We found significantly higher median WBC, CRP, and leukocyturia in children with APN than with CYS. The risk factors of UTIs were presented in 46.6% of patients, of which 35.6% were children with APN and 61.7% with CYS. The main risk factor was CAKUT, more frequently diagnosed in children with CYS than APN, mainly in children <2 years. The most commonly isolated bacteria were Escherichia coli (74%). There was a higher percentage of urine samples with E. coli in girls than in boys. Other bacteria found were Klebsiella species, Pseudomonas aeruginosa, Proteus mirabilis, and Enterococcus species. Conclusions: Patients with APN were younger and had higher inflammatory markers. Often, fever is the only symptom of UTI in children, and other clinical signs are usually non-specific. The most common UTI etiology is E. coli, regardless of the clinical presentation and risk factors.

Defining effective durations of antibiotic therapy for community-acquired pneumonia and urinary tract infections in hospitalized children

PURPOSE OF REVIEW

Community-acquired pneumonia (CAP) and urinary tract infections (UTI) are two common childhood infections often leading to hospital admission. National guidelines for CAP and UTI in children recommend durations of antibiotic therapy of 10 days and 7-14 days, respectively. Due to concerns of rising antimicrobial resistance and an increased awareness of harms associated with prolonged courses of antibiotics, there is a renewed emphasis on reevaluating commonly prescribed durations of antibiotic therapy across bacterial infections. We describe recent clinical trials and observational studies evaluating durations of therapy for CAP and UTI in adults and children and translate the findings to our suggested approach for selecting durations of antibiotic therapy in hospitalized children.

RECENT FINDINGS

There is a growing body of evidence, primarily in adults, that shorter durations of therapy than are commonly prescribed are just as effective as longer durations for CAP and UTIs.

SUMMARY

Combining clinical trial data from adults with available data in children, we believe it is reasonable to consider 5 days of therapy for CAP, 3-5 days of therapy for cystitis, and 7 days of therapy for pyelonephritis for most hospitalized children with uncomplicated infections.

Nomogram for diagnosing acute pyelonephritis in pediatric urinary tract infection

BACKGROUND

For risk stratification and individualized treatment for children with urinary tract infection (UTI), they must be assessed for the presence of acute pyelonephritis (APN). Our study aimed to combine variables that can predict APN and establish a nomogram for clinical use.

METHODS

In total, 111 children <5 years old hospitalized at Kaohsiung Veterans General Hospital for UTI were classified into APN and simple UTI groups based on a technetium-99 m dimercaptosuccinic acid scan. Their demographic, laboratory test, and renal and urinary bladder sonography (RUBS) data were compared.

RESULTS

Fever peak of >39 °C, serum procalcitonin (PCT) ≥ 0.52 pg/mL, C-reactive protein (CRP) ≥ 2.86 mg/dL, and abnormal RUBS findings were independent variables for predicting APN in children. The nomogram established using the aforementioned variables had an area under the receiver operating characteristic curve (AUC) of 0.89, which was higher than those of PCT and CRP alone (0.776 and 0.774, respectively).

CONCLUSION

The combination of four variables had the highest power in predicting APN in children with UTI. The established nomogram is practical for clinical use.

Comparative genomic analysis of ESBL-producing Escherichia coli from faecal carriage and febrile urinary tract infection in children: a prospective multicentre study

Background

The reliability of ESBL-producing Escherichia coli (ESBL-Ec) faecal carriage monitoring to guide probabilistic treatment of febrile urinary tract infection (FUTI) in children remains unclear.

Objectives

To compare the genomic characteristics of ESBL-Ec isolates from faecal carriage and FUTI to assess their correlation and identify a FUTI-associated virulence profile.

Methods

We conducted a prospective multicentre hospital and ambulatory-based study. We analysed the genotypes and virulence factors of both faecal and FUTI ESBL-Ec by whole genome sequencing. Correlations were assessed by non-parametric Spearman coefficient and virulence factors were assessed by chi-squared tests with Bonferroni correction.

Results

We included 218 ESBL-Ec causing FUTI and 154 ESBL-Ec faecal carriage isolates. The most frequent ST was ST131 (44%) in both collections. We found high correlation between carriage and ESBL-Ec FUTI regarding genes/alleles (rho = 0.88, P < 0.0001) and combinations of virulence genes, MLST and serotypes (rho = 0.90, P < 0.0001, rho = 0.99, P = 0.0003, rho = 0.97, P = 0.005 respectively). Beside this strong correlation, we found five genes that were significantly associated with FUTI (papC, papGII, hlyC, hek and traJ). The strongest association with FUTI was found with adhesin gene allele papGII (54% in FUTI versus 16% in carriage) and for papGII and gene traJ alone or in combination (63% versus 24%).

Conclusions

The genomic profile of ESBL-Ec causing FUTI in children strongly correlates with faecal carriage isolates except for a few genes. The presence of papGII and/or traJ in a previously identified carriage strain could be used as a marker of uropathogenicity and may guide the empirical antimicrobial choice in subsequent FUTI.

Facklamia hominis pyelonephritis in a pediatric patient: first case report and review of the literature

Background

Pyelonephritis is one of the most serious bacterial illnesses during childhood. Gram-negative organisms account for up to 90% of the cases. Gram-positive bacteria are uncommon causes of urinary tract infections, and only a few cases caused by Facklamia hominis have been reported in the literature.

Case presentation

A five-year-old girl with tracheostomy and gastrostomy and past medical history of congenital lymphangioma presented with a two-week history of with intermittent fever, frequent urination, and vesical tenesmus. Diagnosis of pyelonephritis was made. Urine culture reported colonies with alpha-hemolysis in blood agar at 48-h of incubation and Facklamia hominis was identified by MALDI-TOF. The patient was successfully treated with gentamicin.

Conclusions

This is the first reported case of pyelonephritis by Facklamia hominis in a child, and the second involving infection in a pediatric patient. Although this pathogen is uncommon, current treatment of F. hominis is a challenge for physicians. This case illustrates the requirement to standardize identification and treatment of care to avoid treatment failure and antimicrobial resistance.

Acute pyelonephritis: Increased plasma membrane targeting of renal aquaporin-2

AIM

Aquaporin-2 (AQP2) shuttling between intracellular vesicles and the apical plasma membrane is pivotal in arginine vasopressin-mediated urine concentration and is dysregulated in multiple diseases associated with water balance disorders. Children and adults with acute pyelonephritis have a urinary concentration defect and studies in children revealed increased AQP2 excretion in the urine. This study aimed to analyse AQP2 trafficking in response to acute pyelonephritis.

METHODS

Immunofluorescence analysis was used to evaluate subcellular localization of AQP2 and AQP2-S256A (mimicking non-phosphorylated AQP2 on serine 256) in cells stimulated with bacterial lysates and of AQP2 and pS256-AQP2 in a mouse model at day 5 of acute pyelonephritis. Western blotting was used to evaluate AQP2 levels and AQP2 phosphorylation on S256 upon incubation with bacterial lysates. Time-lapse imaging was used to measure intracellular cAMP levels in response to incubation with bacterial lysates.

RESULTS

In cell cultures, lysates from both uropathogenic and nonpathogenic bacteria-mediated AQP2 plasma membrane targeting and increased AQP2 phosphorylation on serine 256 (pS256) without increasing cAMP levels. Both bacterial lysates induced plasma membrane targeting of AQP2-S256A. Immunofluorescence analysis of renal sections from mice after 5 days of acute pyelonephritis revealed apical plasma membrane targeting of AQP2 and pS256-AQP2 in inner medullary collecting ducts.

CONCLUSION

Uropathogenic bacteria induce AQP2 plasma membrane targeting in vitro and in vivo. cAMP levels were not elevated by the bacterial lysates and AQP2 plasma membrane targeting could occur without S256 phosphorylation. This may explain increased AQP2 excretion in the urine during acute pyelonephritis.

Molecular Study of Escherichia albertii in Pediatric Urinary Tract Infections

Background:

There are insufficient data about the presence ofE. albertiias a causative organism in urinary tract infection in pediatric patients. Objective: The present study aimed to detectE. albertiiby polymerase chain reaction (PCR) for detection ofuidA, mdh,andlysPgenes among isolatedE.colifrom children with urinary tract infection.

Methods:

The present study was a cross-sectional retrograde study which was carried out on 100 isolates of phenotypically confirmedE.colidetected in urine samples of children suffering from urinary tract infection. The isolates were subjected to molecular identification by PCR foruidA, mdh,andlysPgenes.

Results:

E. albertiiwas identified by PCR in 7% of the isolates andE.coliwas identified in 93% of the isolates. TwomdhandlysPgenes were detected forE. albertiiand theuidAgene forE. coli.E. albertiiisolates had marked resistance to gentamicin (71.4%), followed by resistance to ciprofloxacin (57.1%), meropenem and imipenem (42.9% each) and ESBL activity by double discs method was reported in 57.1% of the isolates. However, none of the isolates had shown resistance to nalidixic acid and only one isolate had resistance to norfloxacin. There was a statistically insignificant difference between resistance to the used antibiotics such as aztreonam (P=0.083), ampicillin/clavulanate (P=0.5), ciprofloxacin (P=0.69), gentamicin (P=0.3) and ceftazidime (P=1.00).

Conclusion:

The present study highlights the emergence ofE. albertiias a pathogen associated with urinary tract infections in children. There is marked antibiotic resistance of this pathogen, especially toward extended spectrum beta-lactams antibiotics. The identification method depends mainly on genetic studies. Further longitudinal studies with large number of patients are required to verify the accurate prevalence of this bacterium.

Non-antibiotic interventions for prevention of urinary tract infections in children: a systematic review and meta-analysis of randomized controlled trials

A considerable proportion of children experience a recurrence of urinary tract infection (UTI) following the first episode. While low-dose antibiotic prophylaxis has been the mainstay for the prevention of UTI, recent evidence raised concerns over their efficacy and safety. Hence, we aim to systematically synthesize evidence on the efficacy and safety of non-antibiotic prophylactic interventions for UTI. Using keywords related to study population (children) and intervention (non-antibiotic), we searched CENTRAL, Embase, PubMed, and Web of Science for randomized controlled trials (RCTs) published until August 2020. RCTs comparing any non-antibiotic interventions with placebo/antibiotics for prevention of UTIs in children were considered eligible. We used a random-effect model to provide pooled estimates. Sixteen trials evaluating 1426 participants were included. Cranberry was as effective as antibiotic prophylaxis (RR: 0.92; 95% CI: 0.56-1.50) but better than placebo/no therapy (RR: 0.48; 95% CI: 0.28-0.80) in reducing UTI recurrence. Probiotic therapy was more effective in reducing UTI recurrence (RR: 0.52; 95% CI: 0.29-0.94) when compared with placebo. While probiotic therapy was not better than antibiotics prophylaxis in preventing UTI (RR: 0.82; 95% CI: 0.56-1.21), they have a lower risk of antibiotic resistance (RR: 0.38; 95% CI: 0.21-0.69).Conclusion: Cranberry products and probiotics are the two non-antibiotic interventions that have been chiefly evaluated, reduce the risk of UTI recurrence when compared with placebo in children with a normal urinary tract. The findings from this systematic review suggest that while cranberry and probiotics may be used, there is a definite need to identify better and more acceptable non-antibiotic interventions. What is Known: • Efficacy of the low-dose antibiotic is controversial in preventing UTI and it is associated with increase in the risk of antimicrobial resistance. • Non-antibiotic interventions such as cranberry products are effective in preventing UTI recurrence in adults. What is New: • Cranberry products are effective in reducing the recurrence of UTI in children with normal urinary tract. • Low-quality evidence suggests that probiotics can be a potential prophylactic measure to reduce recurrence of UTI in the pediatric population.

Antibiotic Resistance in Paediatric Febrile Urinary Tract Infections

Febrile urinary tract infection (UTI) is currently considered the most frequent cause of serious bacterial illness in children in the first 2 years of life. UTI in paediatrics can irreversibly damage the renal parenchyma and lead to chronic renal insufficiency and related problems. To avoid this risk, an early effective antibiotic treatment is essential. Moreover, prompt treatment is mandatory to improve the clinical condition of the patient, prevent bacteraemia, and avoid the risk of bacterial localization in other body sites. However, antibiotic resistance for UTI-related bacterial pathogens continuously increases, making recommendations rapidly outdated and the definition of the best empiric antibiotic therapy more difficult. Variation in pathogen susceptibility to antibiotics is essential for the choice of an effective therapy. Moreover, proper identification of cases at increased risk of difficult-to-treat UTIs can reduce the risk of ineffective therapy. In this review, the problem of emerging antibiotic resistance among pathogens associated with the development of paediatric febrile UTIs and the best potential solutions to ensure the most effective therapy are discussed. Literature analysis showed that the emergence of antibiotic resistance is an unavoidable phenomenon closely correlated with the use of antibiotics themselves. To limit the emergence of resistance, every effort to reduce and rationalise antibiotic consumption must be made. An increased use of antibiotic stewardship can be greatly effective in this regard.

Diagnostic value of biomarkers for paediatric urinary tract infections in primary care: systematic review and meta-analysis

Background

Accurate diagnosis of urinary tract infection is essential as children left untreated may suffer permanent renal injury.

Aim

To compare the diagnostic values of biomarkers or clinical prediction rules for urinary tract infections in children presenting to ambulatory care.

Design and setting

Systematic review and meta-analysis of ambulatory care studies.

Methods

Medline, Embase, WOS, CINAHL, Cochrane library, HTA and DARE were searched until 21 May 2021. We included diagnostic studies on urine or blood biomarkers for cystitis or pyelonephritis in children below 18 years of age. We calculated sensitivity, specificity and likelihood ratios. Data were pooled using a bivariate random effects model and a Hierarchical Summary Receiver Operating Characteristic analysis.

Results

Seventy-five moderate to high quality studies were included in this review and 54 articles in the meta-analyses. The area under the receiver-operating-characteristics curve to diagnose cystitis was 0.75 (95%CI 0.62 to 0.83, n = 9) for C-reactive protein, 0.71 (95% CI 0.62 to 0.80, n = 4) for procalcitonin, 0.93 (95% CI 0.91 to 0.96, n = 22) for the dipstick test (nitrite or leukocyte esterase ≥trace), 0.94 (95% CI 0.58 to 0.98, n = 9) for urine white blood cells and 0.98 (95% CI 0.92 to 0.99, n = 12) for Gram-stained bacteria. For pyelonephritis, C-reactive protein < 20 mg/l had LR- of 0.10 (95%CI 0.04–0.30) to 0.22 (95%CI 0.09–0.54) in children with signs suggestive of urinary tract infection.

Conclusions

Clinical prediction rules including the dipstick test biomarkers can support family physicians while awaiting urine culture results. CRP and PCT have low accuracy for cystitis, but might be useful for pyelonephritis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-021-01530-9.

A rare pathogen Raoultella planticola caused urinary tract infection in child with congenital anomalies of kidney and urinary tract: case report

Raoultella planticola was previously considered an environmental organism in soil, water, and plants. However, several cases of human infection have recently been reported in association with R. planticola, some of which have been life-threatening. Most cases were in adults with reduced immunity, with few cases in children. To our knowledge, there have only been two reported cases of urinary tract infection (UTI) caused by R. planticola in children, including one case of cystitis. Here, we present the first case of UTI caused by R. planticola with congenital anomalies of kidney and urinary tract (CAKUT) in a 4-month-old male infant. The patient presented to the emergency department with fever and was diagnosed with UTI. We started third-generation cephalosporins empirically for gram-negative bacteria in the urine, presuming infection with Escherichia coli. On day 1, the patient's fever resolved immediately. On day 2, urine culture was positive for a rare pathogen, R. planticola, and we narrowed antibiotics to first-generation cephalosporins. The patient's fever did not return and he was discharged on day 7. The patient was seen in the clinic 1 week after discharge, with complete resolution of symptoms. Magnetic resonance urography and dynamic renal scintigraphy performed 2 months after discharge revealed severe bilateral hydronephroureter and obstruction of urine flow in the right kidney. As of 6 months after UTI onset, we have continued low-dose cephalexin (10 mg/kg) to prevent the recurrence of UTI and there has been no recurrence. As in this case, children with UTI caused by R. planticola may be associated with CAKUT; therefore, we should actively screen to detect CAKUT. Patients with CAKUT are at high risk of UTI recurrence, so long-term use of unnecessary broad-spectrum antibiotics should be avoided to prevent antimicrobial resistance. However, R. planticola infection is sometimes life-threatening. Hence, it is also important to use sufficiently strong antibiotics for an appropriate period. Although the optimal management of R. planticola infection in children has not been clearly established, we suggest that we can treat UTI caused by R. planticola mainly using first-generation cephalosporins.

Risk factors for kidney scarring and vesicoureteral reflux in 421 children after their first acute pyelonephritis, and appraisal of international guidelines

BACKGROUND

Acute pyelonephritis (AP) is a common bacterial infection in childhood. Follow-up guidelines on these children are controversial. This study aimed to identify risk factors for kidney scarring and vesicoureteral reflux (VUR). Furthermore, international follow-up guidelines were used for simulation to evaluate sensitivity and specificity.

METHODS

Urinary culture-confirmed first-time AP patients (aged 0-14 years) were enrolled (n = 421) from review of patient charts. All underwent kidney ultrasound (US) and a technetium-99m-dimercaptosuccinic acid (DMSA) scan or technetium-99m-mercaptoacetyltriglycine scinti-renography (MAG3) at 4-6 months of follow-up. The international guidelines used for simulation were from the National Institute of Health UK (NICE), the American Association of Paediatrics (AAP) and the Swedish Paediatric Society (SPS).

RESULTS

17.8% presented with an abnormal DMSA/MAG3 at follow-up, 7.1% were diagnosed with VUR grades III-V and 4.7% were admitted for surgery. Non-Escherichia coli infections, abnormal kidney US, elevated creatinine and delayed response to treatment (>48 h) were risk factors for abnormal DMSA findings and VUR grades III-V. NICE and SPS guidelines showed best sensitivity in diagnosing VUR grades III-V (75%) compared with AAP (56%).

CONCLUSIONS

Risk factors are helpful in identifying the children in need of further investigations and minimizing invasive work-up for the rest. International guidelines on follow-up detect a varying number of children with kidney damage and/or significant VUR. Future work must focus on identifying more specific risk factors, better imaging, or specific biomarkers, to enhance sensitivity and specificity in detecting the children at high risk for developing recurrent infections and/or nephropathy.

Low-Dose Antibiotic Prophylaxis Induces Rapid Modifications of the Gut Microbiota in Infants With Vesicoureteral Reflux

Background and Objectives: Maturation of the gut microbiota (GM) in infants is critically affected by environmental factors, with potential long-lasting clinical consequences. Continuous low-dose antibiotic prophylaxis (CAP) is the standard of care for children with vesicoureteral reflux (VUR), in order to prevent recurrent urinary tract infections. We aimed to assess short-term GM modifications induced by CAP in infants. Methods: We analyzed the GM structure in 87 infants (aged 1-5 months) with high-grade VUR, previously exposed or naïve to CAP. Microbial DNA was extracted from stool samples. GM profiling was achieved by 16S rRNA gene-based next-generation sequencing. Fecal levels of short- and branched-chain fatty acids were also assessed. Results: 36/87 patients had been taking daily CAP for a median time of 47 days, while 51/87 had not. In all patients, the GM was predominantly composed by Bifidobacteriaceae and Enterobacteriaceae. Subgroup comparative analysis revealed alterations in the GM composition of CAP-exposed infants at phylum, family and genus level. CAP-exposed GM was enriched in members of Enterobacteriaceae and Bacteroidetes, especially in the genera Bacteroides and Parabacteroides, and showed a trend toward increased Klebsiella, often associated with antibiotic resistance. In contrast, the GM of non-CAP children was mostly enriched in Bifidobacterium. No differences were found in fatty acid levels. Conclusions: In infants with VUR, even a short exposure to CAP definitely alters the GM composition, with increased relative abundance of opportunistic pathogens and decreased proportions of health-promoting taxa. Early low-dose antibiotic exposure might bear potential long-term clinical risks.

Diffusion-Weighted MRI in the Evaluation of Renal Parenchymal Involvement during Febrile Urinary Tract Infections in Children: Preliminary Data

Background: Urinary tract infection (UTI) is the most common infection in pediatric-age patients. Acute pyelonephritis (PNA) represents a worrying situation in pediatric patients due to the risk of sepsis and long-term cicatricial consequences. The purpose of this retrospective study is to evaluate the diagnostic role of DW-MRI in relation to clinical data, to understand if there are any clinical parameters useful in identifying which patients should undergo it. Methods: According to inclusion and exclusion criteria, we enrolled 51 patients ≤15 years old admitted to our Institute between September 2012 and April 2020 with a febrile UTI who underwent DW-MRI evaluation. Clinical, laboratory and imaging data were collected. Statistical analysis was performed. Results: 34 of 51 patients with an fUTI (66.7%) showed signs of acute parenchymal involvement at DW-MRI evaluation. In 27 of these 34 (79.4%), DW-MRI showed multiple areas of pyelonephritis. A statistically significant relationship (p = 0.0004) between older age at admission and pyelonephritis was demonstrated. No statistically significant relationship was found between the other clinical, anamnestic and laboratory parameters and the outcome of DWI. Only two ultrasound examinations allowed the identification of pathological areas on the renal parenchyma. Conclusions: From these preliminary investigations, we can say that selecting the patients with fUTI on whom to perform a DW-MRI is difficult. Nevertheless, thanks to the low cost, the very rare need for sedation and the accuracy in identifying pyelonephritic areas, the use of DW-MRI in patients with febrile UTI seems recommendable.

Diffusion-Weighted MRI in the Evaluation of Renal Parenchymal Involvement during Febrile Urinary Tract Infections in Children: Preliminary Data

Background: Urinary tract infection (UTI) is the most common infection in pediatric-age patients. Acute pyelonephritis (PNA) represents a worrying situation in pediatric patients due to the risk of sepsis and long-term cicatricial consequences. The purpose of this retrospective study is to evaluate the diagnostic role of DW-MRI in relation to clinical data, to understand if there are any clinical parameters useful in identifying which patients should undergo it. Methods: According to inclusion and exclusion criteria, we enrolled 51 patients ≤15 years old admitted to our Institute between September 2012 and April 2020 with a febrile UTI who underwent DW-MRI evaluation. Clinical, laboratory and imaging data were collected. Statistical analysis was performed. Results: 34 of 51 patients with an fUTI (66.7%) showed signs of acute parenchymal involvement at DW-MRI evaluation. In 27 of these 34 (79.4%), DW-MRI showed multiple areas of pyelonephritis. A statistically significant relationship (p = 0.0004) between older age at admission and pyelonephritis was demonstrated. No statistically significant relationship was found between the other clinical, anamnestic and laboratory parameters and the outcome of DWI. Only two ultrasound examinations allowed the identification of pathological areas on the renal parenchyma. Conclusions: From these preliminary investigations, we can say that selecting the patients with fUTI on whom to perform a DW-MRI is difficult. Nevertheless, thanks to the low cost, the very rare need for sedation and the accuracy in identifying pyelonephritic areas, the use of DW-MRI in patients with febrile UTI seems recommendable.

The bacteria and the host: a story of purinergic signaling in urinary tract infections

The local environment forces a selection of bacteria that might invade the urinary tract, allowing only the most virulent to access the kidney. Quite similar to the diet in setting the stage for the gut microbiome, renal function determines the conditions for bacteria-host interaction in the urinary tract. In the kidney, the term local environment or microenvironment is completely justified because the environment literally changes within a few micrometers. The precise composition of the urine is a function of the epithelium lining the microdomain, and the microenvironment in the kidney shows more variation in the content of nutrients, ion composition, osmolality, and pH than any other site of bacteria-host interaction. This review will cover some of the aspects of bacterial-host interaction in this unique setting and how uropathogenic bacteria can alter the condition for bacteria-host interaction. There will be a particular focus on the recent findings regarding how bacteria specifically trigger host paracrine signaling, via release of extracellular ATP and activation of P2 purinergic receptors. These finding will be discussed from the perspective of severe urinary tract infections, including pyelonephritis and urosepsis.

Vesicoureteral reflux is it important to find?

Vesico-ureteral reflux (VUR) has long been recognized as associated with urinary tract infections (UTIs), renal scarring, and chronic kidney disease (CKD). The concept of "reflux nephropathy" was born, whereby the VUR was considered the culprit, predisposing to recurrent UTIs and providing a conduit whereby the infection could ascend to the kidneys resulting in scarring and destruction. The more severe grades of reflux were thought to place the young child at particular risk of CKD. The question being asked in this pro/con debate is whether VUR is indeed the culprit responsible for a significant proportion of children with CKD, a number of whom progress to end-stage kidney failure (ESKF), and is thus important to find and treat, or is it an innocent bystander associated with CKD and ESKF but not the cause. We believe the latter and will present convincing evidence supported by large scale prospective randomized controlled trials that VUR is not the ogre it was thought to be and is not important to find following a UTI (with some exceptions).

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.

Clinical manifestations, laboratory markers, and renal ultrasonographic examinations in 1-month to 12-year-old Iranian children with pyelonephritis: a six-year cross-sectional retrospective study

BACKGROUND

Upper urinary tract infection (UTI) or pyelonephritis may increase the pathogenesis rate and risk of severe complications in children due to kidney atrophy.

OBJECTIVE

A set of clinical symptoms, laboratory markers, and ultrasound findings were assessed to achieve the early diagnosis and prognosis of pyelonephritis in hospitalized pediatrics.

METHODS

A cross-sectional study with 104 Iranian children (95 girls and 9 boys) aged 1 month to 12 years with acute pyelonephritis during 2012-2018 was conducted. The ultrasound examination of kidneys and urinary tract during hospitalization, the incidence of clinical symptoms, and laboratory markers in blood and urine were monitored to identify the best predictive factors of early diagnosis of this bacterial infection.

RESULTS

Three-fourth of the patients had one of the four clinical symptoms of abdominal pain, constipation, dysuria, and vomiting, while others were asymptomatic. A much frequency of pyuria (88.46%), Escherichia coli in urine (92.31%), leukocytosis (81.73%), and high ESR (> 10 mm/h, 92.30%) and CRP (> 10 mg/L, 82.82%) was observed. The kidney and urinary tract ultrasonography only in 32.7% of children revealed findings in favor of pyelonephritis (cystitis, ureteral stones, and hydronephrosis).

CONCLUSION

There was a high frequency of clinical signs and laboratory markers associated with pyelonephritis. Ultrasound alone was not an efficient tool to track febrile UTI as most patients presented normal sonography.

Is it necessary to evaluate urinary tract infection in children with lower respiratory tract infection?

AIM

Although the incidence of urinary tract infection (UTI) in children with lower respiratory tract infection (LRTI) has been reported as 3.1-10.0%, the exact concomitant prevalence is questionable. Here, we evaluated the prevalence and related risk factors of UTI associated with LRTI in children under 36 months of age.

METHODS

We retrospectively reviewed the medical charts of 1574 patients under 36 months of age who were hospitalised with LRTI from January 2017 to December 2019 in a single centre, Seoul, South Korea. Among them, we analysed 278 patients who showed fever and performed urine evaluation. Urine was collected by catheterisation in children under 24 months of age and by voided urine between 24 and 36 months of age.

RESULTS

The prevalence of concomitant UTI and LRTI was 13.6% in children under 24 months of age. Mean age was significantly younger in the UTI versus non-UTI group (6.93 ± 7.26 months vs. 12.61 ± 11.70 months; P < 0.001). When the participants were stratified by age, the prevalence of UTI was significantly higher in children younger than 24 months of age compared to older ones (P = 0.006). UTIs were more prevalent in boys than in girls (14.6% vs. 5.8%, P = 0.018). Peak body temperature, fever duration, premature birth and detected respiratory virus type did not differ between groups.

CONCLUSIONS

It is not uncommon for children with LRTI with fever to be accompanied by UTI. When evaluating for UTI in children with febrile LRTI, age and sex must be considered.

[Bacterial urinary tract infection and subclinical bacteriuria in the dog: a current review]

Bacterial urinary tract infection (UTI) is a common clinical presentation in dogs and a frequent reason for the prescription of antimicrobial drugs. UTI refers to adherence, multiplication and persistence of an infectious agent within the urogenital system. This causes an associated inflammatory response as well as the pertaining clinical signs. Depending on the site of infection, UTI's may be classified as bacterial cystitis, prostatitis or pyelonephritis. In contrast, subclinical bacteriuria (SB) is defined as the presence of a significant number of bacteria in the urine of an individual not showing clinical signs referrable to UTI. UTI's typically occur as a consequence of ascending pathogen migration from the host's own fecal or distal urogenital microbial flora. The most commonly isolated pathogen in cases of UTI and SB is Escherichia coli. The diagnosis is based on clinical signs and the results of urine examination and culture. The recently revised guidelines of the International Society for Companion Animal Infectious Diseases provide detailed recommendations for diagnosis and management of different forms of bacterial UTI's in dogs. Adherence to treatment guidelines will improve treatment success and is imperative in avoiding further deterioration of the antimicrobial resistance situation.

Current Management of Urinary Tract Infection and Vesicoureteral Reflux

Urinary tract infection (UTI) is defined as the growth of a significant number of microorganisms of a single species in the urine, in the presence of symptoms. Symptoms in young children are non-specific such as fever without focus; young infants may manifest with irritability, failure to thrive, jaundice, vomiting and diarrhea. Older children usually have symptoms of cystitis or pyelonephritis. Symptoms of cystitis are dysuria, frequency, new onset incontinence and malodorous urine while symptoms of pyelonephritis are high grade fever, flank pain and vomiting. Rapid urine testing by microscopy for pus cells, dipstick testing for leukocyte esterase and nitrite, and enhanced urinalysis are supportive tests. Urine culture samples should be collected with proper technique and results interpreted for significant growth accordingly. Antibiotic therapy for 7-14 d for complicated UTI and 3-4 d for uncomplicated UTI is adequate. Further evaluation is recommended clinically for bladder-bowel dysfunction and obvious anatomical defects and by imaging for vesicoureteral reflux (VUR), usually by micturating cystourethrography (MCU). Since MCU involves exposure to radiation and urethral catheterization, it is now reserved for children with parenchymal involvement or recurrent UTI. VUR is the backward flow of urine into one or both ureters. Clinical manifestations other than UTI include incidental diagnosis on antenatal ultrasonography. Reflux nephropathy, the renal scarring associated with VUR may manifest clinically as hypertension, proteinuria and renal failure. The management of VUR is primarily with antibiotic prophylaxis. Anatomical correction is indicated in case of breakthrough febrile UTI. No intervention has been shown to reduce renal scarring.

Semiquantitative analysis of power doppler ultrasonography versus Tc-99m DMSA scintigraphy in diagnostic and severity assessment of acute childhood pyelonephritis

BACKGROUND

This study aimed to compare the diagnostic and predictive value of power Doppler ultrasonography (PDU) with Tc-99m dimercaptosuccinic acid (DMSA) renal scintigraphy in pediatric acute pyelonephritis (APN) using a semiquantitative analysis system.

METHODS

A total of 92 children and infants (184 kidneys) were hospitalized with possible APN. All children were examined by PDU and DMSA scintigraphy within 72 hours of admission. An empiric 9-point semiquantitative analysis system was used to sort kidneys into four grades (grade 0-III). Patients with several episodes of APN and congenital structural anomalies were excluded.

RESULTS

Of 184 kidneys, we found 68 abnormal (grade I-III) and 116 normal (Grade 0) with DMSA scintigraphy, and 84 abnormal and 100 normal with PDU. In all, 23 kidneys were shown to be diseased by PDU but normal on DMSA scintigraphy while 7 kidneys showed the opposite trend. The sensitivity and specificity of PDU for diagnosing APN was 89.7% and 80.2%, respectively (P<0.05). In children older than 6 months, the sensitivity was higher (92%, P<0.05) than that in children younger than 6 months (87%, P<0.05). A moderate agreement (41%, P<0.05) on grade was found between the two methods.

CONCLUSIONS

With the help of a semiquantitative analysis system, PDU can obviate the use of DMSA scintigraphy in children older than 6 months for APN diagnosis.

The Effect of Vitamin A on Clinical Manifestations of Recurrent Pyelonephritis in Children

Background: Pyelonephritis as a life-threatening infection often leads to renal scarring, which presumably controls by minerals. Objectives: The aim of this study was pyelonephritis treatment by vitamin A in children. Methods: In the current study,106 cases from Imam Reza pediatric clinic and Amir-Kabir Hospital, considered a study group. Children divided into groups with or without urinary incontinence. Demographic data, clinical manifestations, and urinary biomarkers were evaluated and then statistically analyzed. Results: Our data showed that there is a statistical difference between study groups in terms of dysuria (P = 0.001), abdominal pain (P = 0.001), frequency (P = 0.003), incontinency (P = 0.001), urgency (P = 0.002), intermittency (P = 0.004) and fever (P = 0.002). Conclusions: It has been assumed that vitamin A as a therapeutic agent could be used in children with vesicoureteral reflux induced by Pyelonephritis and congenital anomalies.

Comparative Effectiveness of Antibiotic Treatment Duration in Children With Pyelonephritis

IMPORTANCE

National guidelines recommend treating children with pyelonephritis for 7 to 14 days of antibiotic therapy, yet data are lacking to suggest a more precise treatment duration.

OBJECTIVE

To compare the clinical outcomes of children receiving a short-course vs a prolonged-course of antibiotic treatment for pyelonephritis.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective observational study using inverse probability of treatment weighted propensity score analysis of data from 5 hospitals in Maryland between July 1, 2016, and October 1, 2018. Participants were children aged 6 months to 18 years with a urine culture growing Escherichia coli, Klebsiella species, or Proteus mirabilis with laboratory and clinical criteria for pyelonephritis.

EXPOSURES

Treatment of pyelonephritis with a short-course (6 to 9 days) vs a prolonged-course (10 or more days) of antibiotics.

MAIN OUTCOMES AND MEASURES

Composite outcome of treatment failure within 30 days of completing antibiotic therapy: (a) unanticipated emergency department or outpatient visits related to urinary tract infection symptoms, (b) hospital readmission related to UTI symptoms, (c) prolongation of the planned, initial antibiotic treatment course, or (d) death. A subsequent urinary tract infection caused by a drug-resistant bacteria within 30 days was a secondary outcome.

RESULTS

Of 791 children who met study eligibility criteria (mean [SD] age 9.2 [6.3] years; 672 [85.0%]) were girls, 297 patients (37.5%) were prescribed a short-course and 494 patients (62.5%) were prescribed a prolonged-course of antibiotics. The median duration of short-course therapy was 8 days (interquartile range, 7-8 days), and the median duration of prolonged-course therapy was 11 days (interquartile range, 11-12 days). Baseline characteristics were similar between the groups in the inverse probability of treatment weighted cohort. There were 79 children (10.1%) who experienced treatment failure. The odds of treatment failure were similar for patients prescribed a short-course vs a prolonged-course of antibiotics (11.2% vs 9.4%; odds ratio, 1.22; 95% CI, 0.75-1.98). There was no significant difference in the odds of a drug-resistant uropathogen for patients with a subsequent urinary tract infection within 30 days when prescribed a short-courses vs prolonged-course of antibiotics (40% vs 64%; odds ratio, 0.36; 95% CI, 0.09-1.43).

CONCLUSIONS AND RELEVANCE

The study findings suggest that short-course antibiotic therapy may be as effective as prolonged-courses for children with pyelonephritis, and may mitigate the risk of future drug-resistant urinary tract infections. Additional studies are needed to confirm these findings.

Associations of Plasma Neutrophil Gelatinase-associated Lipocalin, Anemia, and Renal Scarring in Children with Febrile Urinary Tract Infections

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL), a bacteriostatic agent, is known to inhibit erythropoiesis leading to anemia. We aimed to investigate the associations of NGAL, anemia, and renal scarring in children with febrile urinary tract infections (UTIs).

METHODS

We retrospectively reviewed the medical records of 261 children with febrile UTIs. The relationship between the presence of anemia and plasma NGAL levels was investigated. NGAL performance in comparison with serum C-reactive protein (CRP) at admission and after 72 hours of treatment was also evaluated for the prediction of renal scarring as well as acute pyelonephritis (APN) and vesicoureteral reflux (VUR).

RESULTS

Plasma NGAL levels were elevated in patients with anemia compared with those without anemia. Multiple linear regression analysis showed an inverse relationship between NGAL levels and erythrocyte counts (standard β = -0.397, P < 0.001). Increased NGAL, but not CRP, was independently associated with the presence of anemia (odds ratio [OR], 2.37; 95% confidence interval [CI], 1.07-5.27; P < 0.05). Receiver operating curve analyses showed good diagnostic profiles of pre- and post-treatment NGAL for identifying APN, VUR, and renal scarring (all P < 0.05). For detecting renal scars, the area under the curve of post-treatment NGAL (0.730; 95% CI, 0.591-0.843) was higher than that of post-treatment CRP (0.520; 95% CI, 0.395-0.643; P < 0.05). The presence of anemia and elevated NGAL at admission (> 150 ng/mL) were independent risk factors for renal scarring in children with febrile UTIs. With anemia, NGAL levels increased consecutively in children with febrile UTI without renal involvement, with APN without scar, and with APN with renal scarring.

CONCLUSION

Increased plasma NGAL levels may be associated with the presence of anemia and renal scarring in children with febrile UTIs.