Urinary tract infections after renal transplantation

Do Infectious Diseases After Kidney Retransplantation Differ From Those After First Kidney Transplantation?

Background

Infectious diseases (IDs) are highly relevant after solid organ transplantation in terms of morbidity and mortality, being among the most common causes of death. Patients undergoing kidney retransplantation (re-K-Tx) have been already receiving immunosuppressive therapy over a prolonged period, potentially facilitating subsequent infections. Comparing ID events after re-K-Tx and first kidney transplantation (f-K-Tx) can delineate patterns and risks of ID events associated with prolonged immunosuppression.

Methods

We included adult patients with records on f-K-Tx and re-K-Tx in the Swiss Transplant Cohort Study. We analyzed ID events after f-K-Tx and re-K-Tx within the same patients and compared infection rates, causative pathogens, and infection sites. Recurrent time-to-event analyses were performed for comparison of infection rates.

Results

A total of 59 patients with a median age of 47 years (range, 18-73) were included. Overall, 312 ID events in 52 patients occurred. In multivariable recurrent event modeling, the rate of ID events was significantly lower after re-K-Tx (hazard ratio, 0.70; P = .02). More bacterial (68.9% vs 60.4%) and fungal (4.0% vs 1.1%) infections were observed after f-K-Tx but fewer viral infections (27.0% vs 38.5%) as compared with re-K-Tx (P = .11). After f-K-Tx, urinary and gastrointestinal tract infections were more frequent; after re-K-Tx, respiratory tract and surgical site infections were more frequent (P < .001).

Conclusions

ID events were less frequent after re-K-Tx. Affected sites differed significantly after f-K-Tx vs re-K-Tx.

Prevalence and Predictive Factors of Urinary Tract Infection in Kidney Transplant Recipients: A 10-Year Study

OBJECTIVES

Urinary tract infections are the main infectious complications among kidney transplant recipients and are considered as a potential risk factor for poor graft outcomes. However, the risk factors of urinary tract infections are controversial. The purpose of our study was to estimate the incidence and predisposing factors of urinary tract infections in patients undergoing kidney transplant in our teaching hospital of Sahloul, Tunisia.

MATERIALS AND METHODS

We retrospectively analyzed the charts of 141 consecutive adult kidney transplants that were performed at the Department of Nephrology, University Hospital of Sahloul, Tunisia, between January 2007 and April 2016.

RESULTS

Of 141 patients, 72 (51.1%) had urinary tract infections after kidney transplant. Mean age was 32.54 ± 12.1 years; 47.6% were male patients, and 52.4% were female patients. The average time between transplant and early urinary tract infections was 11 days (range, 1-30 days). Among our patient group, 87.8% of urinary tract infections occurred within the first 6 months posttransplant. We collected 205 episodes of urinary tract infections: 66.3% were asymptomatic bacteriuria, 10.2% acute cystitis, and 23.4% pyelonephritis. The estimated risk factors for urinary tract infection included only female sex (P < .05); older age (P = .32), longer duration of catheter (P = .34), and high body mass index (P = .46) were not correlated with urinary tract infection.

CONCLUSIONS

Despite preventive measures, urinary tract infections remain an important cause of morbidity among kidney transplant recipients. In fact, more than half of kidney transplant recipients had at least 1 urinary tract infection after surgery. Female sex was statistically associated with higher risk of urinary tract infection.

Recurrent Urinary Tract Infection in Living Donor Renal Transplant Recipients and the Role of Behavioral Education Program in Management: A Single-Center Experience

BACKGROUND

Urinary tract infections (UTIs) are the most prevalent type of kidney transplant (KT) recipients. We aimed to investigate the incidence, causes, and clinical impact of early recurrent UTI post-living donor KT and to examine the role of behavioral education program in management.

METHODS

This retrospective cohort chart-review study included all KT recipients with recurrent UTI necessitating hospital admission between September 2017 and August 2021. All patients with recurrent UTI were subjected to behavioral education for a month.

RESULTS

UTI was found in 14 of 145 patients (9.6%), with recurrent UTI in 11 (7.6%). A total of 93% of UTIs occurred during the first 6 months post-transplant and represented 52% of KT readmissions during the same period. A total of 64.3% of patients were older than 50 years. The mean (SD) length of hospital stay was 5 (2.5) days, with an equal incidence in both sexes. The most common bacterial isolates in early recurrent UTI were Escherichia coli in 80.9%. Both Extended-spectrum beta-lactamases and multidrug-resistant organisms (resistance in ≥3 drugs) were seen in 82.4% of isolates. Furthermore, the most effective antibiotic was meropenem, with 86.7% effectiveness. A total of 65% of UTIs were managed with a single antibacterial course. A total of 64.3% of patients were older than 50 years. In patients who developed UTI, the mean (SD) serum creatinine was 1.31 (0.52) mg/dL, with a mean increase in serum creatinine of 0.19 mg/dL on having the episodes; at 1 year post-transplant, serum creatinine declined to 1.23 (0.43) mg/dL. Four patients (36%) had no recurrence of UTI after behavioral education.

CONCLUSIONS

The multidrug-resistant bacterial isolates account for 82.4% of the UTIs. Therefore, antibiotic prescription should follow the antimicrobial stewardship guidelines. Behavioral education significantly reduced the incidence of recurrent UTI.

Non-Immunologic Causes of Late Death-Censored Kidney Graft Failure: A Personalized Approach

Despite continuous advances in surgical and immunosuppressive protocols, the long-term survival of transplanted kidneys is still far from being satisfactory. Antibody-mediated rejection, recurrent autoimmune diseases, and death with functioning graft are the most frequent causes of late-kidney allograft failure. However, in addition to these complications, a number of other non-immunologic events may impair the function of transplanted kidneys and directly or indirectly lead to their failure. In this narrative review, we will list and discuss the most important nonimmune causes of late death-censored kidney graft failure, including quality of the donated kidney, adherence to prescriptions, drug toxicities, arterial hypertension, dyslipidemia, new onset diabetes mellitus, hyperuricemia, and lifestyle of the renal transplant recipient. For each of these risk factors, we will report the etiopathogenesis and the potential consequences on graft function, keeping in mind that in many cases, two or more risk factors may negatively interact together.

Early versus late acute graft pyelonephritis: A retrospective analysis of graft and patient outcomes

BACKGROUND

Acute graft pyelonephritis (AGPN) is thought to affect graft and patient survival among renal transplant recipients. The objective was to compare outcomes among early AGPN (<6 months from transplant) versus late AGPN (>6 months from transplant).

METHODS

This retrospective study analysed 150 patients with AGPN dividing them into early and late AGPN from 2008 to 2016. Predictors of graft loss and mortality were compared using logistic regression analysis. Graft survival and patient survival were analysed using Kaplan-Meyer survival plots.

RESULTS

55.3% (n = 83) had early AGPN and 44.7% (n = 67) had late AGPN. In an early AGPN group, 13.3% had CMV disease on the follow-up, compared to only 3% in the late AGPN group (p > 0.05). Furthermore, 38.6% had prolonged DJ stent in-situ (> 2 weeks) following transplant surgery in the early AGPN compared to only 19.4% in the late AGPN group (p < 0.05). Recurrent GPN was more common in the late AGPN group - (35.8% versus 18.1%). The presence of renal abscess was predictive of graft loss in Univariate analysis (HR-6.12, p < 0.004). There was decreased death-censored graft survival in the early AGPN group (p = 0.035), without a significant difference in the patient survival among the two groups.

CONCLUSION

The occurrence of early AGPN had a significant impact on long-term graft survival in renal transplant recipients, with no significant effect on patient survival. This study underlines the paramount importance of the prevention of urinary tract infection (UTI) in renal transplant recipients.

Emergency Department Utilization and Serious Bacterial Infection Rates in Children With Renal Transplants

OBJECTIVES

Emergency department (ED) visits by children with solid organ transplants have increased significantly. Our objectives were to describe the common complaints, diagnosis, types, and rates of serious bacterial infection (SBI) in children with renal transplant (RT) who present to the hospital.

METHODS

We conducted a retrospective study from 2012 to 2016 of RT children up to 18 years who presented to the ED or were directly admitted. We excluded patients who presented for a procedure. We collected demographics, transplant type, immunosuppressive data, chief complaints, diagnostic testing with results, interventions performed, and final diagnosis.

RESULTS

We analyzed 131 visits in 29 patients during the study period. Most common chief complaints were infectious (34.4%) and gastrointestinal (26%). Infection was proven in 42.0% of visits with only 3.1% being organ rejection. Serious bacterial infection was diagnosed in 34 visits (26.0%) with urinary tract infection (UTI) being the most common (20.6%). Of the 33 visits for fever, SBI occurred in 16 (48.5%) patients with the most common SBI being UTI 10 (30.3%). Bacteremia occurred in 1 patient and hypotension in 4 patients. Antibiotic administration was the most common intervention performed (78; 59.5%). Significant interventions were uncommon (2 patients). Logistic regression revealed no factors to be associated with SBI.

CONCLUSIONS

Our cohort of children with RT presented most commonly with infections to the hospital with UTI being the most common SBI. Bacteremia and significant interventions were rare. Future studies are needed to identify subgroups of low-risk pediatric RT patients who can possibly be safely discharged home from the ED.

Transplant Ureteral Stenosis after Renal Transplantation: Risk Factor Analysis

INTRODUCTION

The results of kidney transplants have improved dramatically in recent years, leading to reduced morbidity and mortality. Despite continuous improvements, urological complications occur at a rate of 2.6%-15%. Ureteral stenosis of graft ureters is the most common complication, with a probability of 0.5%-6.3%. This study aimed to determine the incidence of ureteral stenosis after kidney transplantation and identify risk factors that distinguish transplant patients with and without ureteral stenosis.

METHODS

This study retrospectively analyzed patients who had undergone kidney transplantation at the Department of Urology of the Friedrich-Alexander University Erlangen-Nuremberg between 2001 and 2015. Forty-seven patients developed ureteral stenosis during the operation. Most of the ureteral stenosis cases occurred in the first 4 months after transplantation. Kaplan-Meier analysis and the log-rank test were used to calculate the cumulative risk, and the Mann-Whitney U test was used nonparametrically. The significance level was set at p < 0.05.

RESULTS

Statistical analysis showed that residual diuresis (p = 0.008), cold ischemia time (CIT) (p = 0.040), the body mass index (p = 0.027), and donor serum creatinine value (p = 0.039) showed a significantly different distribution between recipients with or without ureteral stenosis after kidney transplantation. In multivariate Cox's regression modeling, residual diuresis and the donor serum creatinine level were identified as the only independent predictors of patients' stenosis-free survival.

CONCLUSION

Urological complications not diagnosed and treated in time endanger the success of kidney transplantation. After evaluating the kidney transplantation data of the patients at the Transplant Center Erlangen-Nuremberg from 2001 to 2015, residual diuresis, CIT, the body mass index, and donor serum creatinine value were found to influence the development of ureteral stenosis.

Significance of Asymptomatic Pyelonephritis Found on Kidney Transplant Biopsy

The clinical significance and appropriate management of graft pyelonephritis diagnosed by biopsy are poorly understood.

Methods

We analyzed data from all patients with pyelonephritis on transplant kidney biopsy from January 1998 to December 2019. Patients were divided into 2 groups: those whose urinalysis was positive for urinary tract infection (UA+) and those whose urinalysis was negative (UA-).

Results

There were a total of 101 patients with the diagnosis of pyelonephritis by biopsy during the study period. The mean time from transplant to pyelonephritis diagnosis was 3.3 ± 4 y. Thirty-six (35.6%) of the patients with pyelonephritis on biopsy had a negative UA. Out of 65 patients in the UA+ group, 54 (83%) received antibiotics. Only 12 of the UA- patients (33%) received antibiotics. The use of antibiotics in both the UA+ (P = 0.03) and UA- groups (P = 0.02) compared with no use of antibiotics was associated with better death-censored graft survival. On multivariate analysis, the use of antibiotics (hazard ratio = 0.22, P = 0.001, 95% confidence interval, 0.12-0.61) was associated with improved graft survival.

Conclusion

The finding of pyelonephritis on a transplant kidney biopsy is almost always a surprise but is an important finding. Treatment with antibiotics, regardless of signs or symptoms of urinary tract infection, is associated with improved graft survival.

Sepsis in Immunocompromised Patients Without Human Immunodeficiency Virus

Sepsis remains among the most common complications from infectious diseases worldwide. The morbidity and mortality rates associated with sepsis range from 20% to 50%. The advances in care for patients with an immunocompromised status have been remarkable over the last 2 decades, but sepsis continues to be a major cause of death in this population Immunocompromised patients who are recipients of a solid organ or hematopoietic stem cell transplant are living longer with a better quality of life. However, some of these patients need lifelong treatment with immunosuppressive medications to maintain their transplant status. A consequence of the need for this permanent immunosuppression is the high risk of opportunistic, community, and hospital-acquired infections, all of which can lead to sepsis. In addition, the detection of serious infections may be more challenging owing to patients' lower ability to mount the clinical symptoms that usually accompany sepsis. This article provides an update on the current knowledge of sepsis in immunocompromised patients without human immunodeficiency virus. It reviews the most pertinent causes of sepsis in this population, and addresses the specific diagnostic and therapeutic challenges in neutropenia and solid organ and hematopoietic stem cell transplantation.

A middle east systematic review and meta-analysis of bacterial urinary tract infection among renal transplant recipients; Causative microorganisms

UTI has been reported as the most prevalent infectious complication after-kidney transplantation. This study aimed to evaluate the bacterial urinary tract infection among renal transplant recipients, and causative microorganisms from the Middle East. We searched literatures reporting the prevalence of UTI, bacterial pathogens, and antibiotic resistance pattern from January 1, 2010-May 10, 2020 for patients with renal transplant recipients from the Middle East in international databases. Terms used were; "Urinary tract infection", "UTI", "bacterial pathogens", "bacterial infection", "renal transplant", "kidney transplant", post - renal transplant, "antibiotic resistance", "Middle East", Turkey, Iran, Jordan, Kuwait, Bahrain, Lebanon, United Arab Emirates, Qatar, Cyprus, Yemen, Iraq, Egypt, Palestine, and Syria. Data analyzed using CMA software. The prevalence of UTI among renal transplant recipients from the Middle East varied between 4.5 and 85%. The combined prevalence of UTI was reported by 37.9% (95% Cl: 28.3-48.5). The most prevalent organisms recovered from urine samples of patients with UTI were E. coli and Klebsiella with prevalence rate of 57.5%, and 15%, respectively. Also, Coagulase negative Staphylococcus (15%), and Enterococci (11.2%) were the most predominant among Gram positive microorganisms. The most resistance among Gram negative microorganisms belonged to Ceftazidime with frequency of 90% followed by Carbenicillin and Cephalexin with prevalence of 87.3%, and 84%, respectively. The effective antibiotic was Imipenem (15.2%). Regarding the high UTI rate in renal transplant recipients from the Middle East, and the significant presence of both Gram negative and Gram positive microorganisms as the most prevalent uropathogens after renal transplantation should be considered when selecting empirical antibacterial therapy.

Pediatric Kidney Transplantation in Perú: A Single-Center Initial Experience

BACKGROUND

Pediatric kidney transplantation (PKTx) is the preferred therapy for children with end-stage renal disease (ESRD) worldwide. Regrettably, in Perú, access to PKTx is extremely difficult due to recipient/donor socio-economic status, health care structure and especially, scarcity of organs. Our center (the only pediatric institute in the country) has recently started a PKTx program with good midterm results. The aim of this study was to present our outcomes.

METHODS

Retrospective analysis of prospectively collected data between December 2017 and August 2019. Fourteen PKTx (< 18 years old) were achieved. As per our protocol: pre-implantation/protocol biopsies, antibody assessment (T/B cell flow cytometric plus HLA testing applying polymerase chain reaction-based technology), triple immunosuppression (tacrolimus, mycophenolate mofetil, steroids) and induction therapy was performed in every case.

RESULTS

The recipient's mean age at the time of PKTx was 14.14 ± 2.62, 8/14 (57.14%) were male, 50% developed ESRD due to undetermined etiology, 11/14 (78.57%) received a deceased donor allograft, and 9/14 (64.28%) required induction with thymoglobulin. Postoperative complications included: delayed graft function (1/14, 7.14%), 1 (7.14%) developed gross hematuria associated with allograft disfunction post-protocol allograft biopsy that was managed conservatively and 1 recipient (7.14%) developed grade II oligoastrocytoma, at 10 months post PKTx.

CONCLUSIONS

PKTx is the best therapeutic option for children with ESRD. Our group demonstrated that even in countries with limited resources like Perú, good midterm results can be achieved. Emphasis should be given to improve access to transplantation especially in the setting of pediatric recipients.

Diabetes-associated infections: development of antimicrobial resistance and possible treatment strategies

Diabetes mellitus is associated with various types of infections notably skin, mucous membrane, soft tissue, urinary tract, respiratory tract and surgical and/or hospital-associated infections. The reason behind this frequent association with infections is an immunocompromised state of diabetic patient because uncontrolled hyperglycemia impairs overall immunity of diabetic patient via involvement of various mechanistic pathways that lead to the diabetic patient as immunocompromised. There are specific microbes that are associated with each type of infection and their presence indicates specific type of infections. For instance, E. coli and Klebsiella are the most common causative pathogens responsible for the development of urinary tract infections. Diabetic-foot infections commonly occur in diabetic patients. In this article, we have mainly focused on the association of diabetes mellitus with various types of bacterial infections and the pattern of resistance against antimicrobial agents that are frequently used for the treatment of diabetes-associated infections. Moreover, we have also summarized the possible treatment strategies against diabetes-associated infections.

Recurrent urinary tract infections in kidney transplant recipients during the first-year influence long-term graft function: a single-center retrospective cohort study

Urinary tract infections (UTIs) after kidney transplantation are associated with significant morbidity. However, data on the impact of UTI on graft survival are controversial. We conducted a retrospective cohort study of 380 kidney transplant patients. Recipients with symptomatic UTIs during the first year after transplantation were categorized into three groups: early (< 3 episodes from months 1st to 6th), late (< 3 episodes during months 7th to 12th) and recurrent (≥ 3 episodes throughout the whole first year). Graft function at three years was considered the primary outcome. Symptomatic UTIs occurred in 184 (48.4%) kidney transplant recipients during the first year; 83 (21.8%) patients developed early UTIs, 50 (13.2%) late UTIs and 51 (13.4%) recurrent UTIs. We observed a significant improvement in graft function after three years in all patients (P < 0.001) except those who had recurrent UTIs. A Kaplan-Meier analysis showed that recipients with recurrent UTIs had worse graft outcome (eGFR value < 60 mL/min/1.73 m²) (P = 0.01). Recurrent UTIs was an independent predictor of graft function at three years in a model adjusted for DGF and episodes of acute rejection (Hazard Ratio, 2.2; 95% CI, 1.3 to 3.5; P = 0.001). Recurrent symptomatic UTIs during the first year after transplantation have negative impact on long-term graft function.

Updates on urinary tract infections in kidney transplantation

Urinary tract infection (UTI) represents the most common infection after kidney transplantation; it is associated with an increased risk for acute kidney rejection and impaired graft function in the early post-transplant period. Kidney transplant recipients with UTIs are often clinically asymptomatic due to the immunosuppressive therapy; however, asymptomatic bacteriuria may progress to acute pyelonephritis, bacteremia and urosepsis, particularly in the early post-transplant period, that are independent risk factors for short and long-term graft and patient survival. This article reviews the definitions, incidence, risk factors and the management of UTI in kidney transplant recipients; furthermore, the main controversial and still unanswered questions, regarding the causes of recurrent UTIs, adequate use of antibiotics to avoid antibiotic resistance, dosing and timing for prophylaxis and treatment of symptomatic infections, are also discussed. The emerging definition of urinary microbiota introduces new concepts in understanding the complexity of the disease and might represent the future target for therapeutic interventions.

A randomized clinical trial comparing Nitrofurazone-coated and uncoated urinary catheters in kidney transplant recipients: Results from a pilot study

BACKGROUND

Urinary tract infections are frequent complications early after kidney transplantation, and the use of antimicrobial coated catheters in settings other than transplantation has shown promising results for infection prevention. The purpose of this study was to compare the efficacy of Nitrofurazone-coated silicone urinary catheters with non-impregnated silicone urinary catheters in reducing bacteriuria and urinary tract infections in kidney transplant recipients.

METHODS

This single-center study, randomized controlled trial at the Hospital do Rim, a tertiary referral center in kidney transplantation, located in São Paulo, Brazil. Subjects involved living donor kidney transplant recipients, and were randomized 1:1 ratio with a computer-generated system to a Nitrofurazone-coated silicone urinary catheter and non-impregnated silicone urinary catheter from March 2013 to December 2014. Patients with asymptomatic bacteriuria or urinary tract infection at baseline, deceased kidney transplant donors, patients with known hypersensitivity to nitrofurantoin, pregnancy, and those refusing to sign the informed consent form were excluded from the study.

RESULTS

Two hundred fourteen subjects were randomized and one hundred seventy-six completed the study. There were no differences in the rates of asymptomatic bacteriuria (12.5% in the Nitrofurazone group and 11.4% in the control group, P = 0.99) and urinary tract infection (8% and 6.8%, P = 0.99) and the incidence of side effects was more frequent in the Nitrofurazone-impregnated silicone urinary catheter group (46.6% and 26.1%, P = 0.007).

CONCLUSION

The study suggests that there is no beneficial effect of the employment of Nitrofurazone-coated urinary catheter.

TRIAL REGISTRATION NUMBER

ISRCTN57888785.

Imaging non-vascular complications of renal transplantation

In patients with end-stage renal disease, the treatment of choice for most patients is renal transplantation. Complications that occur after kidney transplant can be broadly divided into vascular and non-vascular categories. Non-vascular complications can further be divided into surgical and medical categories. When evaluating renal transplant imaging, it is helpful to consider the occurrence of complications in a timeline from time of surgery. Ultrasound is often the first modality used for evaluation of renal transplants particularly in the early postoperative period. Contrast-enhanced ultrasound can be a helpful adjunct in evaluating certain complications such as hematoma, rejection, and infection. Computed tomography (CT) is also helpful in accurately diagnosing complications. Surgical complications include perinephric fluid collections (hematoma, urinoma from urine leak, abscess, and lymphocele), urinary obstruction, and incisional fluid collections and hernias. One major category of medical complications that affect the renal parenchyma includes rejection (hyperacute, acute, and chronic), delayed graft function, acute tubular necrosis (ATN), and nephrotoxicity. Infection, renal calculi, and neoplasms such as post-transplant lymphoproliferative disease are medical complications that occur after renal transplantation. It is important for radiologists to be aware of the ultrasound and CT findings of the surgical and medical complications after renal transplant for prompt identification and treatment.

Prevalence of Sexually Transmitted Diseases in Asymptomatic Renal Transplant Recipients

OBJECTIVES

Sexually transmitted diseases, which may be asymptomatic, have the potential to cause serious health problems in renal transplant recipients. The aim of this study was to determine the prevalence of sexually transmitted diseases in sexually active asymptomatic renal transplant patients by using real-time multiplex polymerase chain reaction assays.

MATERIALS AND METHODS

This prospective controlled study was conducted between November 2016 and January 2017 in our hospital. Our study group included 80 consecutive, sexually active asymptomatic patients (40 men and 40 women) who had undergone renal transplant in our hospital and who presented to our outpatient clinic for routine follow-up. We also included a control group of 80 consecutive, sexually active nontransplant patients (40 men and 40 women). All patient samples were tested for Gardnerella vaginalis and obligate anaerobes (Prevotella bivia, Porphyromonas species), Candida species, Mycoplasma hominis, Mycoplasma genitalium, Ureaplasma species, Trichomonas vaginalis, Neisseria gonorrhoeae, Chlamydia trachomatis, herpes simplex virus 1 and 2, and Cytomegalovirus by real-time multiplex polymerase chain reaction.

RESULTS

The prevalences of infection with Gardnerella vaginalis and obligate anaerobes (P = .043), Ureaplasma species (P = .02), and Cytomegalovirus (P = .016) were found to be significantly higher in the study group versus the control group. However, there was no difference between the 2 groups regarding the prevalence of Mycoplasma infection (P = .70).

CONCLUSIONS

Sexually transmitted diseases may occur more frequently in sexually active asymptomatic renal transplant recipients than in nontransplanted individuals. Real-time multiplex polymerase chain reaction analysis may be a suitable method for determining these pathogens.

Results of Real-time Multiplex Polymerase Chain Reaction Assay in Renal Transplant Recipients With Sterile Pyuria

Urinary tract infections are a major cause of morbidity and hospitalization after renal transplantation. Patients treated with immunosuppressive drugs suffer not only from common uropathogens but also from opportunistic infections caused by unusual uropathogens. Sterile pyuria is associated with numerous infectious agents including viruses, fungi, and atypical or fastidious organisms. The objective of this study was to investigate the pathogens using real-time multiplex polymerase chain reaction (rtMPCR) assay in sterile pyuria of renal transplant recipients. In this prospective controlled study, pathogen detection was performed with rtMPCR assay on October 2016 in 60 patients with sterile pyuria who had undergone kidney transplantation. A total of 40 renal transplant patients were determined as the control group. Male-to-female ratio was same. The mean age of the subjects with sterile pyuria was 45.7 ± 12.1 (25-74). The mean duration after transplantation was 28.8 ± 3.97 (3-102) months. Pathogens were detected with rtMPCR in 61.7% of sterile pyuria group. This rate was significantly higher compared with the control group (P < .001). Two or more different pathogens were found in 13 (21.7%) patients in sterile pyuria group. The pathogens found included cytomegalovirus in 10 patients (19%), Gardnerella vaginalis and obligate anaerobes in 20 patients (38%), Ureaplasma spp in 17 patients (33%), Candida spp in 2 patients (4%), Mycoplasma hominis in one patient (2%), herpes simplex virus-2 in one patient (2%), and Trichomonas vaginalis in one patient (2%). Sterile pyuria may indicate the presence of genitourinary pathogens that cannot be detected with conventional urine culture method in renal transplantation patients. rtMPCR is an accurate and convenient method for detection of multiple potential pathogens of sterile pyuria in renal transplant patients.

Cyclosporine A Induces MicroRNAs Controlling Innate Immunity during Renal Bacterial Infection

Urinary tract infections (UTIs) mainly due to uropathogenic Escherichia coli (UPEC) are one of the most frequent complications in kidney-transplanted patients, causing significant morbidity. However, the mechanisms underlying UTI in renal grafts remain poorly understood. Here, we analysed the effects of the potent immunosuppressive agent cyclosporine A (CsA) on the activation of collecting duct cells that represent a preferential site of adhesion and translocation for UPEC. CsA induced the inhibition of lipopolysaccharide- induced activation of collecting duct cells due to the downregulation of the expression of TLR4 via the microRNA Let-7i. Using an experimental model of ascending UTI, we showed that the pretreatment of mice with CsA prior to infection induced a marked fall in cytokine production by collecting duct cells, neutrophil recruitment, and a dramatic rise of bacterial load, but not in infected TLR4-defective mice kidneys. This effect was also observed in CsA-treated infected kidneys, where the expression of Let-7i was increased. Treatment with a synthetic Let-7i mimic reproduced the effects of CsA. Conversely, pretreatment with an anti-Let-7i antagonised the effects of CsA and rescued the innate immune response of collecting duct cells against UPEC. Thus, the utilisation of an anti-Let-7i during kidney transplantation may protect CsA-treated patients from ascending bacterial infection.

Timing and Predictors of Early Urologic and Infectious Complications After Renal Transplant: An Analysis of a New York Statewide Database

OBJECTIVES

The most common complications after renal transplant are urologic and are a cause of significant morbidity in a vulnerable population. We sought to characterize the timing and predictors of urologic complications after renal transplant using a statewide database.

MATERIALS AND METHODS

We queried the New York Statewide Planning and Research Cooperative System database to identify patients who underwent renal transplant from 2005 to 2013. Postoperative complications included hydronephrosis, ureteral stricture, vesicoureteral reflux, nephrolithiasis, and urinary tract infections. Cox proportional hazards model was used to assess independent predictors of urologic complications.

RESULTS

In total, 9038 patients were included in the analyses. Urologic complications occurred in 11.3% of patients and included hydronephrosis (12.0%), nephrolithiasis (2.8%), ureteral stricture (2.4%), and vesicoureteral reflux (1.5%). We found that 23% experienced at least one urinary tract infection. On multivariate analysis, predictors of urologic complications included medicare insurance, hypertension, and prior urinary tract infection. Graft recipients from living donors were less likely to experience urologic complications than deceased-donor kidney recipients (P < .001).

CONCLUSIONS

Urologic complications occur in a significant proportion of renal transplants. Further study is needed to identify risk factors for complications after renal transplantation to decrease morbidity in this vulnerable population.

Children after renal transplantation hospitalized for fever: Is empirical antibiotic treatment always justified?

Infections are a major cause of morbidity and mortality after renal transplantation. However, data focusing on children are scarce. The objective of this study was to investigate the frequency and predictors of bacterial infection in pediatric renal transplant recipients in a specific setting of hospitalization due to fever. Clinical and laboratory data were retrospectively collected for all pediatric renal transplant recipients hospitalized for fever in a national renal transplantation center from 2004 to 2012. One hundred and sixty-eight hospital admissions for fever of 52 children were analyzed. A bacterial etiology was diagnosed in 85 admissions (50.6%); 49 cases (57.6%) were documented microbiologically and 36 (42.4%) clinically. Risk factors and markers of bacterial infection included older age, presence of a central venous catheter, sonographic findings, and elevated inflammatory indices. C-reactive protein level was a more sensitive marker than white blood cell count and absolute neutrophil count. In patients without identified risk factors, no bacterial infections were diagnosed. Pediatric renal transplant recipients hospitalized for fever are at high risk of bacterial infections and usually require empirical antibiotic treatment at admission. However, there is a minority of low-risk patients in whom clinicians may consider withholding antibiotic treatment with close follow-up.

The prevalence and predictive factors of urinary tract infection in patients undergoing renal transplantation: A meta-analysis

BACKGROUND

Urinary tract infections (UTIs) are the main cause of infectious complications in renal transplant (RTx) recipients and are considered as a potential risk factor for poorer graft outcomes. However, the risk factors of UTIs are controversial. We estimated the incidence and predisposing factors of UTIs in patients undergoing RTx.

METHODS

Seventeen studies (6,671 patients) evaluated the prevalence and the risk factors of UTIs in patients with RTx published January 2000-October 2014 were included. The data were pooled using the fixed effect model or DerSimonian-Laird random effect model according to I².

RESULTS

Thirteen eligible articles with a total of 3,364 patients were evaluated and the pooled prevalence of UTIs was 38.0% (95% confidence interval [CI], 29%-47%; P < .01). The estimated risk factors for UTI include female sex (odds ratio [OR], 3.11; 95% CI, 2.10-4.13), older age (OR, 1.032; 95% CI, 1.01-1.04), duration of catheter (OR, 1.52; 95% CI, 1.03-2.03), acute rejection episodes (OR, 1.64; 95% CI, 1.11-2.41), and receiving a kidney from a deceased donor (OR, 1.28; 95% CI, 1.09-1.52).

CONCLUSIONS

More than one-third of RTx patients had at least 1 UTI after surgery. Female sex, older age of the recipient, long duration of catheter, acute rejection episodes, and cadaveric donor were associated with higher risk of UTI.

Minimizing the Number of Urological Complications After Kidney Transplant: A Comparative Study of Two Types of External Ureteral Stents

OBJECTIVES

The aim of this study was to evaluate the effects of 2 types of external ureteral stents on the number of urological complications after kidney transplant.

MATERIALS AND METHODS

Data were retrospectively collected from 366 consecutive transplants performed between January 2013 and January 2015 in our hospital, in which an external ureteral stent was placed during surgery and removed after 9 days. Urological complications were defined as urinary leakage or ureteral stenosis requiring percutaneous nephrostomy placement.

RESULTS

A total of 197 patients received a straight stent with 2 larger side holes (type A; 8F "Covidien" tube; Covidien, Dublin, Ireland) and 169 patients received a single J stent with 7 smaller side holes (type B; 7F "Teleflex" single J stent; Teleflex Medical, Athlone, Ireland). We found a significantly higher number of percutaneous nephrostomy placements with type A stents, with 34 (17%) versus 16 (9%) in type B (P = .030). Reason for percutaneous nephrostomy placement, occurrence of stent dysfunction, and need for early removal (< 8 days) were equal in both groups (P = .397), whereas incidence of rejection and urinary tract infection were higher in type B stent group. Patient and graft survival did not differ between the groups.

CONCLUSIONS

Use of the type B stent was associated with less urological complications compared with the type A stent.

Differential gene expression pattern in biopsies with renal allograft pyelonephritis and allograft rejection

Differentiating acute pyelonephritis (APN) from acute rejection (AR) in renal allograft biopsies can sometimes be difficult because of overlapping clinical and histologic features, lack of positive urine cultures,and variable response to antibiotics. We wanted to study differential gene expression between AR and APN using biopsy tissue. Thirty-three biopsies were analyzed using NanoString multiplex platform and PCR (6 transplant baseline biopsies, 8 AR, 15 APN [8 culture positive, 7 culture negative], and 4 native pyelonephritis [NP]). Additional 22 biopsies were tested by PCR to validate the results. CXCL9, CXCL10, CXCL11, and IDO1 were the top differentially expressed genes, upregulated in AR. Lactoferrin (LTF) and CXCL1 were higher in APN and NP. No statistically significant difference in transcript levels was seen between culture-positive and culture-negative APN biopsies. Comparing the overall mRNA signature using Ingenuity pathway analysis, interferon-gamma emerged as the dominant upstream regulator in AR and allograft APN, but not in NP (which clustered separately). Our study suggests that chemokine pathways in graft APN may differ from NP and in fact resemble AR, due to a component of alloreactivity, resulting in variable response to antibiotic treatment. Therefore, cautious addition of steroids might help in resistant cases of graft APN.

Comparison of the effect of co-trimoxazole and co-trimoxazole plus ciprofloxacin in urinary tract infection prophylaxis in kidney transplant patients

Background:

Urinary tract infection (UTI) as an important infection in the setting of renal transplantation carries the high mortality and morbidity rate. Thus, the prevention of this infection should receive higher priority. However, bacterial resistance to antibiotics is on the rise, with limited data to guide prophylaxis. The purpose of this study was to compare the effect of sulfamethoxazole-trimethoprim (SMZ/TMP) and SMZ/TMP plus ciprofloxacin for prophylaxis of UTI in renal transplant recipients.

Materials and Methods:

In a clinical trial study, 50 patients were included and divided into two groups of 25 using block randomization. Patients in Group I received prophylactic SMZ/TMP and those in Group II received ciprofloxacin plus SMZ/TMP. The incidence of UTI in the two groups at 1, 3, and 6 months after transplantation was evaluated. This study was registered in Iranian Registry of Clinical Trial (IRCT number: IRCT 2015120823743N1).

Results:

Of the 61 patients older than 18 years at the time of transplantation, 50 were included. UTI was documented in 8 patients (32%) in Group I and 3 (12%) in Group II (P = 0.026). The average time for the development of the first case of infection was the same for both groups (P = 0.241), and it was at its maximum in the 1^st month. Urinary infections caused by Escherichia coli, the dominant strain, were the same in both groups (P = 0.673).

Conclusions:

Our study shows that the addition of 1 month course of ciprofloxacin lowered the incidence of UTI. More studies are needed to confirm the efficacy of this approach.

Profile of infections in renal transplant recipients from India

Background:

Infectious disorders are a major cause of concern in renal transplant recipients (RTRs) leading to considerable morbidity and mortality. We studied the profile and outcomes of infectious disorders in a cohort of RTR.

Materials and Methods:

In this prospective, observational study, we evaluated all RTR who presented with the features of infection. We also included asymptomatic patients with microbiological evidence of infection. We excluded patients with acute rejection, drug toxicity, and malignancy. Descriptive statistics were used to analyze the results.

Results:

The study population (n = 45, 35 male and 10 female) had a mean age of 35.5 ± 10.4 years and follow-up after transplant was 2.1 ± 1.7 years. Urinary tract infection (UTI, n = 15) is the most common infection followed by tuberculosis (TB, n = 8), cytomegalovirus (n = 6), candidiasis (n = 7), and hepatitis (n = 11). Miscellaneous infections such as cryptosporidiosis and pneumocystis were seen in 10 patients. Simultaneous infections with two organisms were seen in 7 patients. Four patients succumbed to multiorgan dysfunction following sepsis, another 4 patients developed chronic graft dysfunction, while the remaining 35 RTR had a good graft function.

Conclusion:

Infectious complications are very common in the posttransplant period including UTI and TB. Further large scale studies are required to identify the potential risk factors leading to infections in RTR.

Urinary Tract Infection among Renal Transplant Recipients in Yemen

Urinary tract infection (UTI) is the most common complication following kidney transplantation (KT), which could result in losing the graft. This study aims to identify the prevalence of bacterial UTI among KT recipients in Yemen and to determine the predisposing factors associated with post renal transplantation UTI. A cross sectional study included of 150 patients, who underwent KT was conducted between June 2010 and January 2011. A Morning mid-stream urine specimen was collected for culture and antibiotic susceptibility test from each recipient. Bacterial UTI was found in 50 patients (33.3%). The prevalence among females 40.3% was higher than males 29%. The UTI was higher in the age group between 41-50 years with a percentage of 28% and this result was statistically significant. Predisposing factors as diabetes mellitus, vesicoureteral reflux, neurogenic bladder and polycystic kidney showed significant association. High relative risks were found for polycystic kidney = 13.5 and neurogenic bladder = 13.5. The most prevalent bacteria to cause UTI was Escherichia coli represent 44%, followed by Staphylococcus saprophyticus 34%. Amikacin was the most effective antibiotic against gram-negative isolates while Ciprofloxacin was the most effective antibiotic against Staphylococcus saprophyticus. In conclusion, there is high prevalence of bacterial UTI among KT recipients in Yemen. Diabetes mellitus, vesicoureteral reflux, neurogenic bladder, polycystic kidney and calculi were the main predisposing factors.

Sepsis in the severely immunocompromised patient

The prevention and treatment of sepsis in the immunocompromised host present a challenging array of diagnostic and management issues. The neutropenic patient has a primary defect in innate immune responses and is susceptible to conventional and opportunistic pathogens. The solid organ transplant patient has a primary defect in adaptive immunity and is susceptible to a myriad of pathogens that require an effective cellular immune response. Risk for infections in organ transplant recipients is further complicated by mechanical, vascular, and rejection of the transplanted organ itself. The immune suppressed state can modify the cardinal signs of inflammation, making accurate and rapid diagnosis of infection and sepsis difficult. Empiric antimicrobial agents can be lifesaving in these patients, but managing therapy in an era of progressive antibiotic resistance has become a real issue. This review discusses the challenges faced when treating severe infections in these high-risk patients.

Vitamin D deficiency is an independent risk factor for urinary tract infections after renal transplants

Vitamin D deficiency is frequently found in patients with renal transplants (RTxs). Because vitamin D plays indispensable roles in the immune system, there may be an association between vitamin D deficiency and infection in these patients, but this has not been fully elucidated. Therefore, this study investigated the impact of pre-RTx vitamin D deficiency on urinary tract infection (UTI) development after RTx.We measured 25-hydroxyvitamin D3 (25(OH)D3) levels in 410 patients 2 weeks before they underwent RTx. Vitamin D deficiency was defined as 25(OH)D3 <10 ng/mL. The primary outcome was UTI occurrence after RTx. Cox proportional hazard analysis determined whether vitamin D deficiency was independently associated with UTI.The mean 25(OH)D3 level was 12.8 ± 6.9 ng/mL, and 171 patients (41.7%) were vitamin D deficient. During a median follow-up duration of 7.3 years, the UTI incidence was significantly higher in vitamin D-deficient patients (52 patients, 30.4%) compared with vitamin D-nondeficient patients (40 patients, 16.7%) (P = 0.001). Moreover, multivariate Cox proportional hazard analysis showed that vitamin D deficiency was an independent predictor of UTI after RTx (hazard ratio 1.81, 95% confidence interval 1.11-2.97, P = 0.02).Vitamin D deficiency was an independent risk factor for UTI after RTx; hence, determining 25(OH)D3 levels might help to predict infectious complications after RTx.

A Nationwide Assessment of the Burden of Urinary Tract Infection among Renal Transplant Recipients

Objective. Evaluate the prevalence and outcomes of urinary tract infection (UTI) among renal transplant recipients. Methods. A secondary analysis of the Nationwide Inpatient Sample 2009–2011 was conducted. Survey-weighted multivariable regression analyses were used to examine the impact of UTI on transplant complications, total charges, and length of stay. Results. A total of 1,044 renal transplant recipients, representing a population estimate of 49,862, were included in the study. UTI was most common in transplant recipients with hypertension (53%) and prevalence was noted to be 28.2 and 65.9 cases per 1,000 for men and women, respectively. UTI increased the likelihood of transplant complications (182% for men, 169% for women). Total charges were 28% higher among men as compared to 22% among women with UTI. Such infection also increased the length of stay by 87% among men and 74% among women. Discussion. UTI in renal transplant recipients was associated with prolonged length of stay, total charges, and increased odds of transplant complications. Interventions to prevent UTI among such patients should be a priority area for future research and practice.

Acute pyelonephritis in renal allografts: a new role for microRNAs?

BACKGROUND

Acute pyelonephritis (APN) versus acute rejection (AR) is a frequently encountered diagnostic and therapeutic dilemma in kidney transplants. Variable culture results, overlapping histologic features, and persistent graft dysfunction despite antibiotics are frequently encountered. Therefore, we explored the utility of intragraft microRNA profiles to distinguish between allograft APN and AR.

MATERIALS AND METHODS

Between 2003 and 2011, we identified 49 patients with biopsy features of APN, within the first 2 years posttransplant. MicroRNA profiling was performed on 20 biopsies (normal kidney, n=4; unequivocal AR, n=5; features of APN, n=11).

RESULTS

Only 32% (16/49) of the patients had concomitant positive urine cultures at biopsy, and in 8 of 16 patients, colony count was less than 10 CFU/mL. In 14 of 49 patients, positive urine culture did not coincide with the biopsy, and in 19 of 49 patients, urine cultures were negative. On microRNA profiling, good clustering was seen among the normal kidneys and among AR biopsies. Among the 11 biopsies with features of APN, 4 biopsies showed good clustering with a pattern distinct from AR; (these patients recovered graft function with antibiotics); 7 of 11 biopsies showed heterogeneity in microRNA profiles and variable outcomes with antibiotic treatment. We identified a panel of 25 microRNAs showing statistical difference in expression between AR and APN. MiR-99b, miR-23b let-7b-5p, miR-30a, and miR-145 were validated using qPCR.

CONCLUSION

Allograft pyelonephritis can be a diagnostic and therapeutic challenge. A gestalt approach is required. In addition to histology and cultures, differential intragraft microRNA expression may prove helpful to distinguish APN from AR in renal allograft biopsies.

Emerging trends in infections among renal transplant recipients

Outcomes following renal and simultaneous kidney-pancreas transplants have improved significantly due to better surgical techniques and improved modalities of antirejection therapy. However, infection remains a significant cause of morbidity and mortality. The use of new modalities of immunosuppression and routine use of antimicrobial prophylaxis has changed the pattern of infections post-transplantation. Cytomegalovirus remains a significant problem and BK virus has emerged as an important pathogen. New antimicrobial agents are now available to treat infection, however, antimicrobial resistance remains a concern.

The antibacterial shield of the human urinary tract

Antibacterial peptides and proteins maintain the sterility of the human urinary tract. A broad-spectrum antimicrobial protein, ribonuclease 7 (RNase 7), previously discovered to play a role in controlling the growth of bacteria on human skin, has now been shown to have an important antibacterial function in the human urinary tract.

Cyclosporine A impairs nucleotide binding oligomerization domain (Nod1)-mediated innate antibacterial renal defenses in mice and human transplant recipients

Acute pyelonephritis (APN), which is mainly caused by uropathogenic Escherichia coli (UPEC), is the most common bacterial complication in renal transplant recipients receiving immunosuppressive treatment. However, it remains unclear how immunosuppressive drugs, such as the calcineurin inhibitor cyclosporine A (CsA), decrease renal resistance to UPEC. Here, we investigated the effects of CsA in host defense against UPEC in an experimental model of APN. We show that CsA-treated mice exhibit impaired production of the chemoattractant chemokines CXCL2 and CXCL1, decreased intrarenal recruitment of neutrophils, and greater susceptibility to UPEC than vehicle-treated mice. Strikingly, renal expression of Toll-like receptor 4 (Tlr4) and nucleotide-binding oligomerization domain 1 (Nod1), neutrophil migration capacity, and phagocytic killing of E. coli were significantly reduced in CsA-treated mice. CsA inhibited lipopolysaccharide (LPS)-induced, Tlr4-mediated production of CXCL2 by epithelial collecting duct cells. In addition, CsA markedly inhibited Nod1 expression in neutrophils, macrophages, and renal dendritic cells. CsA, acting through inhibition of the nuclear factor of activated T-cells (NFATs), also markedly downregulated Nod1 in neutrophils and macrophages. Silencing the NFATc1 isoform mRNA, similar to CsA, downregulated Nod1 expression in macrophages, and administration of the 11R-VIVIT peptide inhibitor of NFATs to mice also reduced neutrophil bacterial phagocytosis and renal resistance to UPEC. Conversely, synthetic Nod1 stimulating agonists given to CsA-treated mice significantly increased renal resistance to UPEC. Renal transplant recipients receiving CsA exhibited similar decrease in NOD1 expression and neutrophil phagocytosis of E. coli. The findings suggest that such mechanism of NFATc1-dependent inhibition of Nod1-mediated innate immune response together with the decrease in Tlr4-mediated production of chemoattractant chemokines caused by CsA may contribute to sensitizing kidney grafts to APN.

Stented ureterovesical anastomosis in renal transplantation: does it influence the rate of urinary tract infections?

Objective

Our objective was to evaluate the impact of routine use of double-J stents on the incidence of urinary tract infection after renal transplantation.

Methods

We conducted a retrospective-comparative single-centre study in 310 consecutive adult deceased donor kidney recipients transplanted from 2002 to 2006. Patients were divided in two groups, with or without urinary stent implantation. To evaluate the predictive factors for UTI, donor and recipients pre- and post-transplantation data were analysed. Early urological complications and renal function within 12 months of transplantation were included as well.

Results

A total of 157 patients were enrolled to a stent (ST) and 153 patients to a no-stent (NST) group. The rate of urinary tract infection at three months was similar between the two groups (43.3% ST vs. 40.1% NST, p = 0.65). Of the identified pathogens Enterococcus and Escherichia coli were the most common species. In multivariate analysis neither age nor immunosuppressive agents, BMI or diabetes seemed to have influence on the rate of UTI. When compared to males, females had a significantly higher risk for UTI (54.0% vs. 33.5%).

Conclusion

Prophylactic stenting of the ureterovesical anastomosis does not increase the risk of urinary tract infection in the early postoperative period.

Community-acquired urinary tract infection in kidney transplantation: risk factors for bacteremia and recurrent infection

BACKGROUND/PURPOSE

Urinary tract infection (UTI) is the most common type of infectious complication among kidney transplant patients. However, the antibiotic susceptibility of causative microorganisms and risk factors for concomitant bacteremia and recurrent infection are rarely discussed.

METHODS

This was a retrospective cohort review of kidney transplant recipients who had received follow-up in the past 10 years at the Chung-Shan Medical University (Taichung, Taiwan). Only community-acquired and symptomatic UTIs were included in this study.

RESULTS

During the 53 ± 22 months of follow-up, 99 patients developed 167 episodes of UTI. Forty-two (25%) episodes had concomitant bacteremia. Escherichia coli was the most common causative microorganism, and strains with resistance to multiple commonly used empirical antibiotics began to emerge. The independent risk factors for UTI with concomitant bacteremia in multivariate analysis were immunosuppression with tacrolimus (adjusted odds ratio [AOR] 3.17; 95% confidence interval [CI] 1.29-7.75; P = 0.011) and baseline serum creatinine level >1.3 mg/dL before first UTI (AOR 2.55; 95% CI 1.02-6.36; P = 0.045). However, there were no factors that were significantly associated with recurrent infection.

CONCLUSION

From this study, we found that E coli tends to have resistance to commonly used empirical antibiotics in this modern era and that patients who use the immunosuppressant tacrolimus and have baseline serum creatinine level >1.3 mg/dL before their first UTI have a tendency to suffer from concomitant bacteremia and even sepsis.

Recurrent urinary tract infections in kidney transplant recipients

Urinary tract infections (UTIs) are the most common infectious complication after kidney transplantation (KT). Recurrent UTIs after KT can contribute to increased morbidity and may also be associated with graft loss and mortality. Though several risk factors like female gender, diabetes mellitus, presence of ureteric stents, native kidney disease with urological malformations and re-transplantation have been associated with recurrent UTIs after KT, vesicoureteric reflux appears to be a unique risk factor in this patient population. The emergence of drug-resistant pathogens as causative agents for post-transplant recurrent UTIs poses a significant therapeutic challenge. The use of pathogen-specific antibiotic therapy guided by culture and sensitivity data is warranted. The optimal duration of antimicrobial therapy for recurrent UTIs in renal transplant recipients remains uncertain.