Predicting the Risk of Breakthrough Urinary Tract Infections: Primary Vesicoureteral Reflux

Scoring system to evaluate meaningful fecal impaction in patients with lower urinary tract dysfunction with simple radiography (KUB)

PURPOSE

The management of bowel bladder disorder (BBD) has only been indicated for subjective constipation without objective evidence. We attempted to highlight the radiological findings in patients with BBD and construct a scoring system to identify patients with BBD prior to treatment.

MATERIALS AND METHODS

Forty-five patients with lower urinary tract dysfunction (LUTD) received polyethylene glycol for 2 months before bladder medication for LUTD. Based on partial response to LUTD following treatment, we divided the patients into LUTD-fecal impaction (FI) and LUTD not attributed to FI (LUTD-NFI) groups. Pre/post-treatment kidney, ureter, and bladder (KUB) were compared with respect to several radiographic parameters. Items with significant changes after treatment were included in the scoring system. The accuracy and inter-rater agreement were also evaluated.

RESULTS

Cecal dilation, descending colon dilation, fecal quality, and overall haziness were found to undergo significant changes after laxative treatment. We assigned 0 to 2 points for each item, with a total score of 8. Receiver operating characteristic curve analysis revealed a cutoff value of 5 between LUTD-FI and LUTD-NFI, with 79% sensitivity and 88% specificity. The scoring system was instructed to six doctors who were unaware of it and was then tested on previous patients, which showed a substantial concordance rate (κ=0.79, p<0.05).

CONCLUSIONS

Fecal scoring system based on KUB was beneficial in identifying children with LUTD attributed to FI. This may provide an opportunity to obtain objective FI data as an alternative to subjective assessment of constipation.

Antimicrobial prophylaxis for vesicoureteral reflux: which subgroups of children benefit the most?

BACKGROUND

While the Randomized Intervention for Children with Vesicoureteral Reflux (RIVUR) trial found that long-term antimicrobial prophylaxis reduced the risk of urinary tract infection (UTI) recurrences by 50%, 10 children had to be treated for one to benefit (i.e., observed number needed to treat (NNT) of 10). Accordingly, we re-analyzed RIVUR data to systematically identify subgroups of children with vesicoureteral reflux (VUR) with a smaller NNT.

METHODS

Using patient-level data from the RIVUR trial, we applied penalized regression methods including the baseline age, VUR grade, type of index UTI, and bowel-bladder dysfunction (BBD) as covariates to identify subgroups.

RESULTS

We identified four relevant subgroups of children that appear to benefit from long-term antimicrobial prophylaxis, all with observed NNTs smaller than or equal to 5: children with grade IV VUR, BBD, and febrile index UTI (1% of the sample), children with BBD and febrile index UTI (7% of the sample), children with BBD (12% of the sample), and children with grade IV VUR (8% of the sample).

CONCLUSIONS

Use of long-term antimicrobial prophylaxis appears to be particularly relevant for children with BBD (and any grade of VUR) and those with grade IV VUR (regardless of BBD status). However, because details regarding the treatment of BBD are not available, further studies are needed to fully determine the role of prophylactic antimicrobials in the management of children with VUR who have BBD.

Pattern of urinary tract infection in children with vesicoureteric reflux: Does breastfeeding reduce the occurrence of urinary tract infection?

Introduction

The protective factors against urinary tract infections (UTIs) in the setting of vesicoureteric reflux (VUR) remain poorly defined. Breastfeeding was suggested as a protective factor against UTI, but its role remains undetermined in this highly susceptible population.

Objectives

The objective of the study was to identify the pattern and risk factors of UTI and investigate the effect of breastfeeding on UTI occurrence in VUR children.

Materials and Methods

This was a mixed-method design, whereby the first part was a cross-sectional study that included children who were diagnosed with VUR and were assessed for their UTI pattern. The second part was a case-control study, which involved contacting the mothers of the children enrolled and questioning them about their breastfeeding pattern, and UTI development was assessed.

Results

Our study included 62 children with a median age of 4.4 (interquartile range = 21) months at diagnosis. Of those, 37 (60%) were male and 25 (40%) were female. Most UTIs occurred in the first 3 months of life, and the first episodes were more frequent in males. Constipation was significantly associated with the occurrence of UTI (relative risk [RR] =1.750 [95% confidence interval (CI): 1.231-2.489], P = 0.003). Children with breakthrough UTIs were more likely to have been breastfed for <9 months (odds ratio [OR] = 4.091 [95% CI: 1.287-13.002], P = 0.015) and to have been exclusively breastfed for <2 months (OR = 4.600 [95% CI: 1.337-15.823], P = 0.012).

Conclusion

Children with VUR are more susceptible to UTIs in their 1st year of life. Constipation is a major risk factor for UTI occurrence in VUR children and should be aggressively managed. Breastfeeding for longer durations showed promising protective features against breakthrough UTIs.

Laparoscopic and Robot-assisted Laparoscopic Reimplantation for Lower Ureter Pathology. A Multi-institutional Comparative Study in 1343 Patients

OBJECTIVE

To evaluate the outcomes of children with vesicoureteral reflux (VUR) and obstructive megaureter (OM) utilizing various laparoscopic and robot-assisted approaches.

MATERIALS AND METHODS

Retrospective review of all pediatric laparoscopic and robot-assisted cases for lower ureter pathology was performed between 2016-2022 in 13 academic centers worldwide. Five surgical approaches were assessed: LEUR, LVCUR, LDECUR, RALUR, and RADECUR.

RESULTS

One thousand three hundred forty-three patients (490 boys and 853 girls) with a median age of 30 months (IQR 12-63) were treated at 13 centers. Nine hundred and eight patients (68%) underwent reimplantation due to VUR (unilateral in 818 and bilateral in 90 patients). Four hundred thirty-five (32%) had a surgery due to ureterovesical junction (UVJ) obstruction. Mean length of follow-up was 14 months (IQR 8-33). Median operative time was 202 minutes (IQR 142-220) in the robotic arm compared to 240 minutes (IQR 160-267) in the laparoscopic (P = .45). Intracorporeal excisional tapering was performed in 118 (8%) of the patients. Six patients in the OM group required additional surgery due to progressive obstruction. In the VUR group, 84% underwent voiding cystourethrography postoperatively. 5.6% showed residual reflux. Grade 1-2 Clavien-Dindo complications occurred in 10 patients (0.7%) and 6 (0.4%) in the laparoscopic and robotic arm, respectively. Grade 3 complications occurred in 17 (1.2%) and 8 (0.5%) in both arms, respectively. Surgical success was achieved in 96% of patients.

CONCLUSION

Laparoscopic and robot-assisted laparoscopic approaches are simple, safe, and effective for treating all grades of VUR and OM. Robot-assisted approach is beneficial in terms of operative time, intracorporeal suturing, and lower complications rate.

The role of circumcision in preventing urinary tract infections in children with antenatal hydronephrosis: Systematic review and meta-analysis

INTRODUCTION

Circumcision has been reported to reduce the risk of urinary tract infections (UTIs) in boys with antenatal hydronephrosis (HN). Our aim was to compare the incidence of UTIs in circumcised vs. uncircumcised boys with antenatal HN by conducting a systematic review and meta-analysis.

STUDY DESIGN

A comprehensive search was performed until December 2022. Comparative studies were evaluated according to Cochrane collaboration recommendations. Assessed measures included: UTIs, continuous antibiotic prophylaxis (CAP) use, renal outcomes, and circumcision complications. Odds ratios (OR) and mean difference with 95% confidence interval (CI) were extrapolated from available data. Random-effects meta-analysis were performed.

RESULTS

Twenty-three studies describing 9093 boys with antenatal HN were identified, including 4677 uncircumcised and 4416 circumcised boys. Overall effect estimates demonstrate that circumcised boys have significantly reduced odds of developing any UTI [OR 0.26, 95%CI 0.21, 0.32; p < 0.001]]. In addition, there a significantly reduced odds of developing UTI when circumcised and on CAP [OR 0.19, 95% CI 0.13, 0.30; p < 0.001]. When stratifying by etiology, circumcision reduced the odds of UTI in boys with isolated HN [OR 0.33, 95% CI 0.16, 0.68; p = 0.003], vesicoureteral reflux [OR 0.23, 95% CI 0.13, 0.42; P < 0.00001], or with posterior urethral valves [OR 0.29, 95% CI 0.13, 0.64; p = 0.002].

DISCUSSION

Circumcision reduces the incidence of UTIs in boys with antenatal HN. This review is limited by the varied definitions of UTIs and inconsistent reporting on HN etiology, renal outcomes, and circumcision complications.

CONCLUSIONS

Circumcision should be considered in boys with antenatal HN to prevent the risk of developing UTI. Further research is warranted to individualize the prophylactic role of circumcision for patients with HN.

Antimicrobial prophylaxis for vesicoureteral reflux: which subgroups of children benefit the most?

Background

While the Randomized Intervention for children with Vesicoureteral Reflux (RIVUR) trial found that long-term antimicrobial prophylaxis reduced the risk of urinary tract infection (UTI) recurrences by 50%, 10 children had to be treated with long-term antimicrobial prophylaxis for one to benefit (i.e., observed number needed to treat (NNT) of 10). Accordingly, we re-analyzed RIVUR data to systematically identify subgroups of children with vesicoureteral reflux (VUR) with a smaller NNT.

Methods

Using patient-level data from the RIVUR trial, we applied penalized regression methods including the baseline age, VUR, and bowel-bladder dysfunction (BBD) as covariates to identify subgroups that consider the trade-off between absolute risk difference and size.

Results

We identified three relevant subgroups of children that appear to benefit from long-term antimicrobial prophylaxis, all with NNTs smaller than the NNT of 10. Children with grade IV VUR and BBD, 1% of the RIVUR sample, had a NNT of 2; children with BBD, 12% of the RIVUR sample, had a NNT of 4; children with BBD (and any grade VUR) or with grade IV VUR (regardless of BBD status), which was the combination of the first two subgroups and included 19% of children in the RIVUR sample, had a NNT of 4.

Conclusions

Use of long-term antimicrobial prophylaxis appears to be particularly relevant for children with BBD (and any grade of VUR) or those with grade IV VUR (regardless of BBD status) who were at high risk of UTI recurrences.

Circumcision reduces urinary tract infection in children with antenatal hydronephrosis: Systematic review and meta-analysis

INTRODUCTION

Urinary tract infection (UTI) is more prevalent in boys with antenatal hydronephrosis (ANH). Circumcision is known to lessen the risk of UTI. This study was performed to examine the associations between circumcision and UTI among patients with ANH.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses standards were followed for conducting this systematic review and meta-analysis. PubMed, ScienceDirect, EMBASE, and Cochrane Library databases were searched through August 4th, 2022 to identify eligible studies. The risk of bias was measured using the Newcastle-Ottawa Scale (NOS). Review manager 5.4 was used for all analysis.

RESULTS

A total of 21 studies involving 8,968 patients with ANH were included in the meta-analysis. The incidences of UTI were 18.1% in the uncircumcised group and 4.9% in the circumcised group. From analysis, circumcision had significant protective effect against UTI with pooled OR of 0.28 (95% CI 0.23-0.32). The significant protective effects were also found in subgroup analysis of hydronephrosis etiology, including vesicoureteral reflux (pooled OR of 0.24; 95% CI 0.17-0.32), obstructive hydronephrosis (pooled OR of 0.34; 95% CI 0.21-0.53), and posterior urethral valve (pooled OR of 0.28; 95% CI 0.16-0.52).

CONCLUSION

Our meta-analysis showed that circumcision was associated with a decreased incidence of UTI in children with ANH. This benefit was consistent irrespective of the underlying cause of hydronephrosis.

Abnormal DMSA renal scan findings and associated factors in older children with vesicoureteral reflux

AIM

There are scanty data on the rate of abnormal Tc-99 m dimercaptosuccinic acid (DMSA) renal scintigraphy and associated factors in children older than 5 years with diagnosis of VUR. We do not have knowledge about which older children should undergo DMSA after VUR diagnosis. This study aims to assess the rate of abnormal DMSA findings and associated factors in children older than 5 years of age diagnosed with VUR.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of 258 children with VUR diagnosed at or older than 5 year age. 179 children [42 (23.5%) males and 137 (76.5%) females] with complete data were included. 268 reflux units were compared according to gender, bilaterality, grade, reflux phase at voiding cystourethrography, febrile urinary tract infection (fUTI), lower urinary tract dysfunction (LUTD), and DMSA findings with uni- and multivariate analysis.

RESULTS

The median age was 110 (60-216) months. VUR grades were I, II, and III in 197 (73.6%) units and IV-V in 71 (26.4%). 138 (51.5%) renal units had abnormal DMSA. VUR grade (p < 0.01), unilaterality (p = 0.048), and fUTI (p = 0.031) in univariate but only grade and unilaterality in multivariate analysis are significantly associated with abnormal DMSA. Although reflux at filling phase was predominant in high-grade VUR group, reflux at voiding phase (p = 0.006) in low-medium-grade (1-3) VUR was associated with abnormal DMSA.

CONCLUSION

Children older than 5 years of age diagnosed with VUR should be regarded as a high-risk group for abnormal DMSA regardless of gender, unilaterality, grade, reflux phase, fUTI, and LUTD.

Management of Vesicoureteral Reflux: What Have We Learned Over the Last 20 Years?

Vesicoureteral reflux (VUR) is associated with increased risks of urinary tract infection, renal scarring and reflux nephropathy. We review advancements over the last two decades in our understanding and management of VUR. Over time, the condition may resolve spontaneously but it can persist for many years and bladder/bowel dysfunction is often involved. Some factors that increase the likelihood of persistence (e.g., high grade) also increase the risk of renal scarring. Voiding cystourethrography (VCUG) is generally considered the definitive method for diagnosing VUR, and helpful in determining the need for treatment. However, this procedure causes distress and radiation exposure. Therefore, strategies to reduce clinicians' reliance upon VCUG (e.g., after a VUR treatment procedure) have been developed. There are several options for managing patients with VUR. Observation is suitable only for patients at low risk of renal injury. Antibiotic prophylaxis can reduce the incidence of UTIs, but drawbacks such as antibiotic resistance and incomplete adherence mean that this option is not viable for long-term use. Long-term studies of endoscopic injection have helped us understand factors influencing use and the effectiveness of this procedure. Ureteral reimplantation is still performed commonly, and robot-assisted laparoscopic methods are gaining popularity. Over the last 20 years, there has been a shift toward more conservative management of VUR with an individualized, risk-based approach. For continued treatment improvement, better identification of children at risk of renal scarring, robust evidence regarding the available interventions, and an improved VUR grading system are needed.

A scoring system for predicting downgrading and resolution of high-grade infant vesicoureteral reflux

AIM

Aim of the study was to provide a scoring system for predicting downgrading and resolution of infantile high-grade vesicoureteral reflux (VUR).

METHODS

Eighty-nine infants (65 boys) with high-grade VUR (grade 4-5) diagnosed at median age 2.5 months and followed to 39 months had repeated investigations of VUR grade, renal damage/function and bladder function. Recurrent urinary tract infections (UTIs) were registered. Risk variables collected at 1 year were analysed as independent factors for spontaneous resolution to grades ≤2 and 0, using univariable/multivariable logistic regression.

RESULTS

A scoring system was built with a total of 14 points from four independent risk factors (sex, breakthrough UTI, type of renal damage and subnormal glomerular filtration rate). Children with persistent VUR (grade 3-5) had higher scores compared with the group with spontaneous resolution (grade 0-2) (mean 7.9 vs. 4.5, P < .0001). A score of ≥8 points indicated a low probability of VUR resolution (≤14%). The model was considered excellent based on area under the ROC curve (0.82) and showed satisfactory internal validity.

CONCLUSION

This model provides a practical tool in the management of infants born with high-grade reflux. High scores at one year of age indicate a high risk of persistent dilated reflux.

Managing vesicoureteral reflux in children: making sense of all the data

Current management of vesicoureteral reflux (VUR) in children is the result of a steady albeit controversial evolution of data and thinking related to the clinical impact of VUR and urinary tract infection (UTI) in children, the value of clinical screening, and the relative impact of testing and interventions for VUR. While controversy continues, there is consensus on the importance of bladder dysfunction on VUR outcomes, the likelihood of VUR resolution, and the fact that not all children with VUR require active treatment. Early efforts to define risk stratification hold the most promise to provide more patient-specific treatment of UTI and VUR in children.

Pediatric voiding cystourethrography: An essential examination for urologists but a terrible experience for children

Voiding cystourethrography is the most important fluoroscopic examination in pediatric urology for the investigation of lower urogenital tract diseases, such as vesicoureteral reflux or urethral stricture. However, this invasive procedure imposes a significant burden on children and their parents, and recently there has been a paradigm shift in the diagnosis and treatment of vesicoureteral reflux. In the 2011 revision, the American Academy of Pediatrics guidelines on urinary tract infection recommended abandoning routine voiding cystourethrography after the first febrile urinary tract infection. In 2014, the randomized intervention for children with vesicoureteral reflux study recommended discontinuation of routine continuous antibiotic prophylaxis for vesicoureteral reflux. The time is now ripe to radically reconsider indications for voiding cystourethrography and the procedure itself.

Vaccines Against Escherichia coli

Escherichia coli has a complex and versatile nature and continuously evolves from non-virulent isolates to highly pathogenic strains causing severe diseases and outbreaks. Broadly protective vaccines against pathogenic E. coli are not available and the rising in both, multi-drug resistant and hypervirulent isolates, raise concern for healthcare and require continuous efforts in epidemiologic surveillance and disease monitoring. The evolving knowledge on E. coli pathogenesis mechanisms and on the mediated immune response following infection or vaccination, together with advances in the "omics" technologies, is opening new perspectives toward the design and development of effective and innovative E. coli vaccines.

A Reanalysis of the RIVUR Trial Using a Risk Classification System

PURPOSE

The RIVUR (Randomized Intervention for Children with Vesicoureteral Reflux) trial showed a 50% decrease in the risk of urinary tract infection recurrence in children with reflux receiving continuous antibiotic prophylaxis. We reanalyzed the RIVUR data with the purpose of using a risk classification system to identify children who are more likely to benefit from continuous antibiotic prophylaxis.

MATERIALS AND METHODS

Data from 607 children enrolled in the RIVUR trial were obtained from the National Institute of Diabetes and Digestive and Kidney Diseases Central Repository and analyzed. We stratified these children into low and high risk categories. The proportion of children and risk of urinary tract infection recurrence in the stratified treatment groups were compared.

RESULTS

Of the children 385 (63.9%) were stratified into the low risk and 217 (36.1%) into the high risk category. The proportions of children with urinary tract infection recurrence were not significantly different in the low risk category between the placebo and continuous antibiotic prophylaxis groups (p = 0.151), while urinary tract infection recurrence was significantly higher in the placebo group (31.5% vs 11.4%, p = 0.001) for high risk children. Furthermore, high risk children on placebo had a 3.7-fold increased risk of urinary tract infection recurrence during 2 years of followup compared to those on continuous antibiotic prophylaxis.

CONCLUSIONS

Although the RIVUR trial concluded that children with vesicoureteral reflux benefit from continuous antibiotic prophylaxis, our reanalysis of the data demonstrates that high risk children benefit more, with a number needed to treat of 5 compared to 18 in low risk children. The clinical implications of these findings suggest a need to refine current indications for continuous antibiotic prophylaxis in children with reflux, supporting a shift toward a "selective" risk based approach for management.

Critical appraisal of the top-down approach for vesicoureteral reflux

Vesicoureteral reflux (VUR) has been linked to recurrent urinary tract infections (UTIs), renal scarring, hypertension, renal insufficiency and end-stage kidney disease. Different imaging strategies have been proposed to approach children presenting with UTI to sort out patients with significant VUR while minimizing patient morbidity, radiation exposure and financial burden. None of these imaging strategies is universally accepted. The“top-down approach” (TDA) aims at restricting the number of voiding cystourethrograms (VCUGs) and its associated morbidity while identifying patients with clinically-significant reflux. In this approach, children presenting with febrile UTIs are acutely investigated with dimercapto-succinic acid (DMSA) renal scans to identify patients with renal parenchymal inflammation. Those with evidence of renal affection are offered VCUG and late DMSA scan to identify VUR and permanent renal scarring, respectively. Although TDA could identify clinically-significant VUR with high sensitivity, it is not without limitations. The approach segregates patients based on the presence of DMSA cortical lesions omitting the morbidity and the economic burden of UTI. Additionally, some of DMSA lesions are attributed to congenital dysplasia and unrelated to UTI. Ionizing radiation exposure, financial costs, limited availability of DMSA scans in the acute setting, variability in interpreting the results and low yield of actionable findings on DMSA scans are some other limitations. In this review, we tried to address the drawbacks of the TDA and reinforce the value of patient-centered approach for VUR.

Computer model predicting breakthrough febrile urinary tract infection in children with primary vesicoureteral reflux

INTRODUCTION AND OBJECTIVE

Factors influencing the decision to surgically correct vesicoureteral reflux (VUR) include risk of breakthrough febrile urinary tract infection (fUTI) or renal scarring, and decreased likelihood of spontaneous resolution. Improved identification of children at risk for recurrent fUTI may impact management decisions, and allow for more individualized VUR management. We have developed and investigated the accuracy of a multivariable computational model to predict probability of breakthrough fUTI in children with primary VUR.

STUDY DESIGN

Children with primary VUR and detailed clinical and voiding cystourethrogram (VCUG) data were identified. Patient demographics, VCUG findings including grade, laterality, and bladder volume at onset of VUR, UTI history, presence of bladder-bowel dysfunction (BBD), and breakthrough fUTI were assessed. The VCUG dataset was randomized into a training set of 288 with a separate representational cross-validation set of 96. Various model types and architectures were investigated using neUROn++, a set of C++ programs.

RESULTS

Two hundred fifty-five children (208 girls, 47 boys) diagnosed with primary VUR at a mean age of 3.1 years (±2.6) met all inclusion criteria. A total 384 VCUGs were analyzed. Median follow-up was 24 months (interquartile range 12-52 months). Sixty-eight children (26.7%) experienced 90 breakthrough fUTI events. Dilating VUR, reflux occurring at low bladder volumes, BBD, and history of multiple infections/fUTI were associated with breakthrough fUTI (Table). A 2-hidden node neural network model had the best fit with a receiver operating characteristic curve area of 0.755 for predicting breakthrough fUTI.

DISCUSSION

The risk of recurrent febrile infections, renal parenchymal scarring, and likelihood of spontaneous resolution, as well as parental preference all influence management of primary VUR. The genesis of UTI is multifactorial, making precise prediction of an individual child's risk of breakthrough fUTI challenging. Demonstrated risk factors for UTI include age, gender, VUR grade, reflux at low bladder volume, BBD, and UTI history. We developed a prognostic calculator using a multivariable model with 76% accuracy that can be deployed for availability on the Internet, allowing input variables to be entered to calculate the odds of an individual child developing a breakthrough fUTI.

CONCLUSIONS

A computational model using multiple variables including bladder volume at onset of VUR provides individualized prediction of children at risk for breakthrough fUTI. A web-based prognostic calculator based on this model will provide a useful tool for assessing personalized risk of breakthrough fUTI in children with primary VUR.

The role of voiding cystourethrography in the investigation of children with urinary tract infections

Urinary tract infections (UTIs) represent a common bacterial cause of febrile illness in children. Of children presenting with a febrile UTI, 25-40% are found to have vesicoureteral reflux (VUR). Historically, the concern regarding VUR was that it could lead to recurrent pyelonephritis, renal scarring, hypertension, and chronic kidney disease. As a result, many children underwent invasive surgical procedures to correct VUR. We now know that many cases of VUR are low-grade and have a high rate of spontaneous resolution. The roles of surveillance, antibiotic prophylaxis, endoscopic injection, and ureteral reimplantation surgery also continue to evolve. In turn, these factors have influenced the investigation of febrile UTIs. Voiding cystourethrography (VCUG) is the radiographic test of choice to diagnose VUR. Due to its invasive nature and questionable benefit in many cases, the American Academy of Pediatrics (AAP) no longer recommends VCUG routinely after an initial febrile UTI. Nevertheless, these guidelines pre-date the landmark Randomized Intervention of Children with Vesicoureteral Reflux (RIVUR) trial and there continues to be controversy regarding the diagnosis and management of VUR. This paper discusses the current literature regarding radiographic testing in children with febrile UTIs and presents a practical risk-based approach for deciding when to obtain a VCUG.

Does the presence of vesicoureteral reflux affect in vitro uropathogenic E. coli growth rate in urine?

BACKGROUND

Uroepithelial molecules like uroplakins are involved both in the development of urinary tract and in colonization, attachment and invasion of uropathogenic Escherichia coli (UPEC). Uroplakin disorders are also associated with vesicoureteral reflux (VUR). We hypothesized that urine contents, as well as urinary flow, may be altered in VUR, and aimed to determine whether in vitro UPEC growth is increased in urine from the refluxing systems.

METHODS

Children evaluated by voiding cystourethrography for UTI were enrolled. Groups 1 and 2 included children with and without VUR, respectively. Sterile urine samples were obtained from all patients, and 2 × 10(2) cfu/mL UPEC suspension was inoculated into these samples. After incubation for 24 h, colony counts were assessed. Both groups were compared for UPEC growth and colony counts.

RESULTS

Forty-two urine samples were included (21 in each group). UPEC was cultured in 9 (43 %) and 3 (14 %) samples in Groups 1 and 2, respectively (p = 0.040, OR 4.5). Colony counts were similar in both groups (log x; 2.36 ± 0.25 vs. 2.37 ± 0.12, p = 0.923).

CONCLUSION

Inoculation of 2 × 10(2) cfu UPEC resulted in growth in almost half of the urine samples from refluxing systems, while UPEC growth was inhibited in most urine samples from non-refluxing systems suggesting that urine contents in refluxing units change in such a way that UPEC growth is facilitated.