Risk Factors for Urinary Tract Infection After Renal Transplantation and its Impact on Graft Function in Children and Young Adults

Different profiles of acute graft pyelonephritis among kidney recipients from standard or elderly donors

Background

Acute graft pyelonephritis (AGPN) is a relatively common complication in kidney transplants (KTs); however, the effects on allograft function, diagnostic criteria, and risk factors are not well established.

Methods

Retrospective analysis of all consecutive adult KTs was performed between 01 January 2011 and 31 December 2018 (follow-up ended on 31 December 2019) to examine the association between the diagnosis of AGPN (confirmed with magnetic resonance imaging [MRI]) during the first post-transplantation year and graft outcomes.

Results

Among the 939 consecutive KTs (≈50% with donors ≥60 years), we identified 130 MRI-confirmed AGPN episodes, with a documented association with recurrent and multidrug-resistant bacterial urinary tract infections (UTIs) (p < 0.005). Ureteral stenosis was the only risk factor associated with AGPN (OR 2.9 [95% CI, 1.6 to 5.2]). KTs with AGPN had a decreased allograft function at the first year (ΔeGFR 6 mL/min/1.73 m2 [-2-15] in non-AGPN vs. -0.2 [-6.5-8.5] in AGPN, p < 0.001), with similar and negative profiles in KTs from standard or elderly donors. However, only KTs with AGPN and a donor <60 years showed reduced death-censored graft survival (p = 0.015); most of this subgroup received anti-thymocyte globulin (ATG) induction (40.4% vs. 17.7%), and their MRI presented either a multifocal AGPN pattern (73.9% vs. 56.7%) or abscedation (28.3% vs. 11.7%). No difference was noted in death-censored graft survival between early (<3 months post-KT) or late (3-12 months) AGPN, solitary/recurrent forms, or types of multidrug-resistant pathogens. Linear regression confirmed the independent role of multifocal pattern, abscedation, ATG induction, and donor age on the eGFR at the first year.

Conclusion

AGPN, influenced by multifocal presentation, ATG induction, donor age, and abscedation, affects kidney function and significantly impacts allograft survival in KTs with donors <60 years.

Native nephrectomy in advanced pediatric kidney disease: indications, timing, and surgical approaches

In pediatric kidney failure, native kidneys may pose a risk to successful transplant outcomes. The indications and timing of native nephrectomy represent a controversial management decision. A lack of high-quality, outcomes-based data has prevented development of evidence-based guidelines for intervention. In this article, we review the published literature on medical indications for native nephrectomy and current knowledge gaps. In addition, we provide a surgical perspective regarding timing and approach.

Vesico-ureteric reflux in children and young people undergoing kidney transplantation

Vesico-ureteric reflux (VUR) into transplanted kidneys in children and young people is a common occurrence, found in 19 to 60% of those who had an anti-reflux procedure and up to 79% in the absence of such a procedure. While VUR is unlikely to be of concern without evidence of symptomatic urinary tract infections, less certainty exists regarding outcomes when the VUR is associated with urinary tract infection (UTI) and transplant pyelonephritis. Issues explored will include additional risk factors that might predispose to UTI, any effect of pyelonephritis on acute and long-term kidney allograft function and practical strategies that may reduce the prevalence of infection.

Renal Transplants Due to Congenital Anomalies of the Kidney and Urinary Tract (CAKUT) Have Better Graft Survival Than Non-CAKUT Controls: Analysis of Over 10,000 Patients

OBJECTIVE

To determine whether graft survival for patients with congenital anomalies of the kidney and urinary tract (CAKUT) is impaired compared to non-CAKUT counterparts.

METHODS

The United States Renal Data System (USRDS) is a national data system that has collected information about end stage renal disease (ESRD) and renal transplantation since 1995. We identified 10,635 first-time renal transplant patients with ESRD attributed to a CAKUT diagnosis transplanted between 1995 and 2018, with follow-up of 7.9 ± 5.8 years. We matched 1:1 with non-CAKUT transplant recipients, using age at transplant, sex, race, year of transplant, and donor-type. We compared renal transplant death-censored graft survival between CAKUT vs non-CAKUT controls, with further stratification for age at transplant and lower urinary tract malformations (LUTM) vs upper urinary tract malformations (UUTM).

RESULTS

Graft survival was better in CAKUT patients with a 5-year survival of 83.3% vs 79.3% (P< .001), and CAKUT status infers a hazard ratio of 0.878 for graft failure on multivariable analysis with Cox regression. Favorability of CAKUT status persisted when stratifying for both pediatric (80.3 vs 77.6% P< .001) and adult (84.5 vs 81.4% P< .001) age groups. Looking within the CAKUT population: comparison of LUTM to UUTM yielded no difference, implying that LUTM is not a risk factor for graft failure. Examining pediatric LUTM alone, graft survival was not better than matched non-CAKUT counterparts with 5-year graft survival of 69%-75% for LUTM adolescents.

CONCLUSION

Renal transplant graft survival is better overall in CAKUT patients as opposed to non-CAKUT counterparts. Pediatric LUTM patients have similar graft survival to controls.

Kidney transplantation in children with CAKUT and non-CAKUT causes of chronic kidney disease: Do they have the same outcomes?

Almost half the children who undergo kidney transplantation (KTx) have congenital abnormalities of the kidney and urinary tract (CAKUT). We compared patient, graft survival, and kidney function at last follow-up between CAKUT and non-CAKUT patients after KTx. We divided the analysis into two eras: 1988-2000 and 2001-2019. Of 923 patients, 52% had CAKUT and 48% non-CAKUT chronic kidney disease (CKD). Of the latter, 341 (77%) had glomerular disease, most frequently typical HUS (32%) and primary FSGS (27%); 102 had non-glomerular disease. CAKUT patients were more often boys, younger at KTx, transplanted more frequently preemptively, but with longer time on chronic dialysis. They had less delayed graft function (DGF) and better eGFR, but higher incidence of urinary tract infection (1 year post-KTx). In both eras, 1-, 5-, and 10-year patient survival was similar in the groups, but graft survival was better in CAKUT recipients vs those with primary glomerular and primary recurrent glomerular disease: Era 1, 92.3%, 80.7%, and 63.6% vs 86.9%, 70.6%, and 49.5% (P = .02), and 76.7%, 56.6%, and 34% (P = .0003); Era 2, 96.2%, 88%, and 73.5% vs 90.3%, 76.1%, and 61% (P = .0075) and 75.4%, 54%, and 25.2% (P < .0001), respectively. Main predictors of graft loss were DGF, late acute rejection (AR), and age at KTx in CAKUT group and disease relapse, DGF, early AR, and number of HLA mismatches in recipients with glomerular disease. Graft survival was better in CAKUT patients. DGF was the main predictor of graft loss in all groups. Disease recurrence and early AR predicted graft failure in patients with glomerular disease.

Risk factors for febrile urinary tract infections in the first year after pediatric renal transplantation

Urinary tract infection is the most common infectious complication following kidney transplant. Anatomic abnormalities, bladder dysfunction, a positive history of febrile urinary tract infection, and recipient age are reported risk factors. The aim of this study was to determine the risk factors for fUTI, which necessitated hospitalization in the first year after renal transplantation in our pediatric transplant population. A retrospective review of 195 pediatric patients who underwent kidney transplant between 2008 and 2017 from a single institution was performed. All patients admitted to the hospital with fUTI were marked for further analyses. The risk factors including age, gender, dialysis type, history of urologic disorders, and preoperative proteinuria for fUTI in the first year after kidney transplantation and graft survivals were investigated. Independent-sample t test and chi-square tests were used for univariate analysis. Exhaustive CHAID algorithm was used for multivariate analysis. The data of 115 male and 80 female patients were retracted. The mean ages of our cohort for males and females were 9.5 ± 5.1 and 10 ± 4.8 years, respectively. The age of the patients at transplant and their gender were found to be a statistically significant risk factors for developing fUTIs. Multivariate analysis showed that fUTI was common in female patients and a subgroup of male patients who had preoperative proteinuria, but no neurogenic bladder had higher risk compared with male patients without proteinuria. Patient surveillance and antibiotic prophylaxis algorithms can be developed to prevent febrile urinary tract infections seen after pediatric kidney transplantation in risky population.

Asymptomatic bacteriuria in pediatric kidney transplant recipients: to treat or not to treat? A retrospective study

BACKGROUND

Urinary tract infections (UTI) are common infectious complications in kidney transplant recipients (KTR); asymptomatic bacteriuria (AB) is also frequent. It is unclear whether treatment of AB reduces subsequent UTI in KTR; no guideline is available in pediatric KTR. In this retrospective study, we analyzed the incidence of AB in pediatric KTR and the impact of screening and treating AB on the onset of subsequent UTI.

METHODS

Thirty-seven pediatric patients were included. Inclusion criteria were the occurrence of one or more episodes of AB between 2 and 24 months post-renal transplantation. Primary outcome was the cumulative incidence of acute pyelonephritis (APN) or lower urinary tract infections (LUTI) occurring between 2 and 24 months post-renal transplantation.

RESULTS

Thirty-seven patients presented 171 AB episodes. One hundred sixty-four AB episodes were untreated (95.9%); among them, 150 episodes (91.5%) were not followed by a clinical infection. Ten episodes (6.1%) led to APN, and 4 (2.4%) to LUTI. There were 53 episodes of APN: 10 (18.9%) after untreated AB and 43 (81.1%) de novo. There were 11 episodes of LUTI: 4 (36.4%) after untreated AB and 7 (63.6%) de novo. Multi-drug resistant bacteria were present in 27% of the patients and in 20% of patients with pre-existing uropathy.

CONCLUSIONS

Our results are not in favor of systematic treatment of AB in pediatric KTR. Notably, limitation of antibiotic treatment is an urgent and important health issue in this population, in order to reduce multi-drug resistant bacteria emergence.

Renal transplantation and predisposition to opportunistic infections

PURPOSE OF REVIEW

Infections represent a significant source of morbidity and mortality after kidney transplantation in children. We review recent advances in epidemiology, assessment, prevention and treatment for several different infections.

RECENT FINDINGS

Infections, such as bacterial urinary tract infection or opportunistic viral infection remain common, may be increasing and represent a large proportion of hospitalization. Extended antiviral agent use reduces the incidence of cytomegalovirus disease but its efficacy to reduce Epstein-Barr virus disease remains controversial. Human herpesvirus-6 and hepatitis E virus represent new infections to keep in mind. Ureteral stenting increases the rate of early UTI. Several new vaccines are now available, but rates of complete vaccination pretransplant are low.

SUMMARY

Infections remain a critical posttransplant issue associated with significant medical burdens. Emerging data on associated risk factors, assessment of and treatment for infections provide clinicians with new knowledge.

Outcome of pediatric renal transplantation in urological versus non-urological causes of end stage renal disease: Does it matter?

INTRODUCTION

Causes for end stage renal disease (ESRD) in children can be categorized into urological causes or non-urological causes. We sought to compare the outcomes of urological and non-urological causes of ESRD in children.

METHODS

Patients were divided into two groups: urological causes of ESRD versus non-urological causes of ESRD. All patients and donors had at least 6 months of follow-up. The main outcomes included the effect on complications and renal function. Comparisons were carried out using the chi-square test or the Student t-test. Multivariate logistic regression analysis was used to define the effect of different variables on the outcome of renal transplantation (Table).

RESULTS

Our study included 123 patients, 91 males. The mean age was 9 years and mean follow up was 46 months. Two-thirds of the patients had non-urological causes of ESRD. Overall survival was 100%, and only one patient needed a graft nephrectomy 3 months after the transplant. The mean estimated glomerular filtration rate was 117 mL/min, and did not differ significantly between the two groups (p = 0.13). Multivariable regression showed that female gender (OR 8.7, 95% CI 2.9-26, p = 0 0.0001) was associated with better renal function, while having a urological cause of ESRD (OR 0.28, CI 0.08-0.98, p = 0 0.05) was associated with worse renal function. Non-urological causes of ESRD were significantly less likely to develop complications following renal transplantation (OR 0.28, CI 0.09-0.89, p = 0 0.03).

CONCLUSION

Female patients with non-urological causes of ESRD are more likely to have better long-term renal functions, and less liable to develop complications following renal transplant.

Risk factors for urological complications following living donor renal transplantation in children

The aim of this study was to detect possible risk factors for UC and UTI following pediatric renal Tx and effect of these complications on outcome. One hundred and eight children who underwent living donor Tx between 2009 and 2015 were retrospectively included. Extraperitoneal approach was used with stented tunneled extravesical procedure. Mean recipient age was 9.89 ± 3.46 years while mean weight was 25.22 ± 10.43 kg. Seventy-three (67.6%) recipients were boys while 92 (85.2%) were related to donors. Urological causes of ESRD were present in 33 (30.6%) recipients (14 [13%] posterior urethral valve, 16 [14.8%] VUR, and 3 [2.8%] neurogenic bladder). Augmentation ileocystoplasty was performed in 9 (8.3%) patients. Mean follow-up was 39.3 ± 17.33 months. UC were detected in 10 (9.3%) children (leakage 4 [3.7%], obstruction 3 [2.8%], and VUR 3 [2.8%]) while UTIs were reported in 40 (37%) children. After logistic regression analysis, UC were significantly higher in children with cystoplasty (44.4% vs 6.1%; P = .001). UTIs were significantly higher in girls (51.4% vs 30.1%; P = .001) and in children with urological causes of ESRD (51.5% vs 30.7%; P = .049). UC and UTI were not significantly associated with increased graft loss or mortality. UC were significantly higher in children with cystoplasty while UTIs were significantly higher in girls and children with urological causes of ESRD. Presence of UC did not affect the rate of graft loss or mortality due to its early detection and proper management.

How to stent the ureter after kidney transplantation in children?-A comparison of two methods of urinary drainage

Ureteral stenting after pediatric renal transplantation serves to prevent obstruction and urinary leakage, but can also cause complications. This study compares the complication rates of both methods. Data were retrospectively collected at Erasmus MC, Rotterdam, the Netherlands (splint group, n = 61) and Hospital for Sick Children, Toronto, Canada (JJ catheter group, n = 50). Outcome measures included urological interventions and incidence of UTIs during the first 3 months post-transplantation. The splint was removed after a median of 9 (IQR 8-12), the JJ catheter after 42 (IQR 36-50) days. Seven (11.5%) children in the splint group needed at least one urological re-intervention versus two in the JJ catheter group (P-value .20). UTIs developed in 19 children (31.1%) in the splint group and in twenty-five (50.0%) children in the JJ catheter group (P-value .04), with a total number of 27 vs. 57 UTIs (P-value .02). Nine (33.3%) vs. 35 (61.4%) of these, respectively, occurred during the presence of the splint (P-value <.001). Children with a JJ catheter developed more UTIs than children with a splint; the latter, however, tended to require more re-interventions. Modification of either method is needed to find the best way to stent the ureter.

Long-term Outcome of 1-step Kidney Transplantation and Bladder Augmentation Procedure in Pediatric Patients

BACKGROUND

Guidelines for bladder augmentation (BA) in kidney transplantation (KT) recipients are not well-defined. In our center, simultaneous BA with KT (BA-KT) is performed. We assessed transplantation outcomes of this unique extensive procedure.

METHODS

A case-control single center retrospective study. Transplantation outcomes were compared with those of KT recipients who did not need BA.

RESULTS

Compared with 22 patients who underwent KT only, for 9 who underwent BA-KT, surgical complications and the need for revision in the early posttransplantation period were similar; early graft function was better: estimated glomerular filtration rate, 96.5 ± 17.1 versus 79.4 ± 16.6 mL/min at 0 to 6 months (P = 0.02); posttransplantation clean intermittent catheterization was more often needed: by 78% (7/9) versus 13% (3/22); and asymptomatic bacteriuria was more common: 100% versus 9% during the first 6 months (P < 0.001), 55% versus 9% (P = 0.02) and 66.6% versus 9% during the first and second years, respectively (P = 0.004). Urinary tract infection (UTI) incidence was also higher: 100% versus 23% during the first 6 months and 44% versus 9% during the second year posttransplantation. Graft function deteriorated significantly in the BA-KT group by the fifth posttransplantation year: estimated glomerular filtration rate was 47.7 ± 39.7 mL/min versus 69 ± 21.3 mL/min, with only 6 (66%) of 9 functioning grafts versus 100% in the KT only group. Causes of graft loss were noncompliance with drug therapy in 2 patients and recurrent UTIs in 2 patients.

CONCLUSIONS

Excellent short-term outcome for simultaneous BA-KT is threatened by graft loss due to a high prevalence of UTIs and patient noncompliance with the demanding complex posttransplantation therapy.

Febrile urinary tract infection after pediatric kidney transplantation: a multicenter, prospective observational study

BACKGROUND

Febrile urinary tract infections (fUTIs) are common after kidney transplantation (KTx); however, prospective data in a multicenter pediatric cohort are lacking. We designed a prospective registry to record data on fUTI before and after pediatric KTx.

METHODS

Ninety-eight children (58 boys and 40 girls) ≤ 18 years from 14 mid-European centers received a kidney transplant and completed a 2-year follow-up.

RESULTS

Posttransplant, 38.7% of patients had at least one fUTI compared with 21.4% before KTx (p = 0.002). Before KTx, fUTI was more frequent in patients with congenital anomalies of kidneys and urinary tract (CAKUT) vs. patients without (38% vs. 12%; p = 0.005). After KTx, fUTI were equally frequent in both groups (48.7% vs. 32.2%; p = 0.14). First fUTI posttransplant occurred earlier in boys compared with girls: median range 4 vs. 13.5 years (p = 0.002). Graft function worsened (p < 0.001) during fUTI, but no difference was recorded after 2 years. At least one recurrence of fUTI was encountered in 58%.

CONCLUSION

This prospective study confirms a high incidence of fUTI after pediatric KTx, which is not restricted to patients with CAKUT; fUTIs have a negative impact on graft function during the infectious episode but not on 2-year graft outcome.

Management of urinary tract infection in solid organ transplant recipients: Consensus statement of the Group for the Study of Infection in Transplant Recipients (GESITRA) of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) and the Spanish Network for Research in Infectious Diseases (REIPI)

BACKGROUND

Urinary tract infections (UTIs) are one of the most common infections in solid organ transplant (SOT) recipients.

METHODS

Experienced SOT researchers and clinicians have developed and implemented this consensus document in support of the optimal management of these patients. A systematic review was conducted, and evidence levels based on the available literature are given for each recommendation. This article was written in accordance with international recommendations on consensus statements and the recommendations of the Appraisal of Guidelines for Research and Evaluation II (AGREE II).

RESULTS

Recommendations are provided on the management of asymptomatic bacteriuria, and prophylaxis and treatment of UTI in SOT recipients. The diagnostic-therapeutic management of recurrent UTI and the role of infection in kidney graft rejection or dysfunction are reviewed. Finally, recommendations on antimicrobials and immunosuppressant interactions are also included.

CONCLUSIONS

The latest scientific information on UTI in SOT is incorporated in this consensus document.

Viral surveillance and subclinical viral infection in pediatric kidney transplantation

The more potent immunosuppressive therapy that has successfully reduced the incidence of acute rejection and improved graft outcomes has also resulted in a higher incidence of viral complications. Sensitive molecular methods now allow for the detection of subclinical viral infection, which is increasingly recognized due to the adoption of routine post-transplant viral surveillance protocols. The goal of viral surveillance is the detection of subclinical viral infection that triggers an intervention; one that either prevents progression to viral disease or leads to early diagnosis of viral disease, which is associated with improved outcomes. Knowledge of the epidemiology and natural history of subclinical viral infection and viral disease, as well as patient-specific risk factors, is required to establish the optimal surveillance schedule which achieves the goal of early diagnosis. Evidence that detection of subclinical viral infection can impact viral disease is variable depending on the virus. This review will summarize the current data on the role of viral surveillance for BK virus (BKV), cytomegalovirus (CMV), and the Epstein-Barr virus (EBV) in the pediatric kidney transplant population.

Infections in transplant patients

Recipients of solid organ transplants (SOT) need primary care providers (PCPs) who are familiar with their unique needs and understand the lifelong infectious risks faced by SOT patients because of their need for lifelong immunosuppressive medications. SOT recipients can present with atypical and muted manifestations of infections, for which the knowledgable PCP will initiate a comprehensive evaluation. The goal of this article is to familiarize PCPs with the infectious challenges facing SOT patients. General concepts are reviewed, and a series of patient cases described that illustrate the specific learning points based on common presenting clinical symptoms.

Decrease in and management of urolithiasis after kidney transplantation

PURPOSE

Urolithiasis after kidney transplantation can involve several contributing factors and the treatment strategy is open to question. We determined the incidence and management of urolithiasis in kidney recipients.

MATERIALS AND METHODS

We retrospectively reviewed a single center series of 3,000 kidney graft recipients during 32 years to identify those with urolithiasis. We analyzed data by the prevalence per decade, including perioperative procedures (preoperative assessment, anastomosis type and urinary drainage) and long-term followup (urinary stenosis, time to presentation, size, site, treatment type, renal function and survival).

RESULTS

We identified 31 cases and noted a significant decrease in incidence from 2.1% to 0.6% during the 3 decades. Excluding 4 cases of donor in situ stones the mean time to diagnosis was 8.5 years. Surgical risk factors were ureteral obstruction in 41% of cases, infravesical obstruction in 14% and urinary-digestive anastomosis in 14%. A total of 12 cases (38%) were observed exclusively with 2 of spontaneous passage. With minor adaptations all mini-invasive procedures, including extracorporeal shock wave lithotripsy, endoscopy and percutaneous nephrolithotomy, were feasible in graft recipients. Antegrade procedures were facilitated by the ventral position of the graft. Eight patients (25%) were treated with open surgical ureteroureteral anastomosis.

CONCLUSIONS

Prevention with a perioperative Double-J® stent and early treatment of ureteral obstruction have decreased and stabilized the urolithiasis rate at around 0.6%. Careful surveillance or any currently available instrumental treatments of urinary stones can be valid options.

Urinary tract infection in renal transplantation

INTRODUCTION

Urinary tract infection (UTI), especially recurrent UTI, is a common problem, occurring in >75% of kidney transplant (KTX) recipients. UTI degrades the health-related quality of life and can impair graft function, potentially reducing graft and patient survival. As urologists are often involved in treating UTI after KTX, previous reports were searched to elucidate underlying causes, risk factors and treatment options, as well as recommendations for prophylaxis of UTI after KTX.

METHODS

Pubmed/Medline was searched and international guidelines and recommendations for prevention and treatment of UTI after KTX were also assessed.

RESULTS

Most studies on UTI after KTX have a small sample, and are descriptive and retrospective. Many transplant- and recipient-related risk factors have been identified. While asymptomatic bacteriuria is often treated, even though some studies advise against it, symptomatic UTI should be treated empirically after collecting urine for microbiological analysis, to avoid the development of transplant pyelonephritis with a high chance of urosepsis. The duration of treatment has not been determined in studies and recommendations refer to the treatment of complicated UTI in the non-transplant population. Prophylaxis has not been the focus of studies either.

CONCLUSION

UTI after KTX is still largely an under-represented field of study, despite many recipients developing UTI after KTX. Prospective studies on this topic are urgently needed.