Antibiotics for asymptomatic bacteriuria in kidney transplant recipients

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

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

Early versus late removal of urinary catheter after kidney transplantation

BACKGROUND

The optimal treatment for end-stage kidney disease is kidney transplantation. During the operation, a catheter is introduced into the bladder and remains in place postoperatively to allow the bladder to drain. This decreases tension from the cysto-ureteric anastomosis and promotes healing. Unfortunately, urinary catheters can pose an infection risk to patients as they allow bacteria into the bladder, potentially resulting in a urinary tract infection (UTI). The longer the catheter remains in place, the greater the risk of developing a UTI. There is no consensus approach to the time a catheter should remain in place post-transplant. Furthermore, the different timings of catheter removal are thought to be associated with different incidences of UTI and postoperative complications, such as anastomotic breakdown.

OBJECTIVES

This review aimed to compare patients who had their catheter removed < 5 days post-transplant surgery to those patients who had their catheter removed ≥ 5 days following their kidney transplant. Primary outcome measures between the two groups included: the incidence of symptomatic UTIs, the incidence of asymptomatic bacteriuria and the incidence of major urological complications requiring intervention and treatment.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 13 April 2023 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs comparing timing of catheter removal post-transplantation were eligible for inclusion. All donor types were included, and all recipients were included regardless of age, demographics or type of urinary catheter used.

DATA COLLECTION AND ANALYSIS

Results from the literature search were screened by two authors to identify if they met our inclusion criteria. We designated removal of a urinary catheter before five days (120 hours) as an 'early removal' and anything later than this as a 'late removal.' The studies were assessed for quality using the risk of bias tool. The primary outcome of interest was the incidence of asymptomatic bacteriuria. Statistical analyses were performed using the random effects model, and results were expressed as relative risk (RR) with 95% confidence intervals (CI). Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Two studies (197 patients) were included in our analysis. One study comprised a full-text article, and the other was a conference abstract with very limited information. The risk of bias in the included studies was generally either high or unclear. It is uncertain whether early versus late removal of the urinary catheter made any difference to the incidence of asymptomatic bacteriuria (RR 0.89, 95% Cl 0.17 to 4.57; participants = 197; I2 = 88%; very low certainty evidence). Data on other outcomes, such as the incidence of UTI and the incidence of major urological complications, were lacking. Furthermore, the follow-up of patients across the studies was short, with no patients being followed beyond one month.

AUTHORS' CONCLUSIONS

A high-quality, well-designed RCT is required to compare the effectiveness of early catheter removal versus late catheter removal in patients following a kidney transplant. At the present time, there is insufficient evidence to suggest any difference between early and late catheter removal post-transplant, and the studies investigating this were generally of poor quality.

[Do we need to treat asymptomatic bacteriuria in immunocompromised patients? : A rapid review]

BACKGROUND

Antimicrobial resistance (AMR), especially multidrug resistant Escherichia coli strains, is a problem even in Europe. That is why inadequate usage of antibiotic therapy should be avoided, especially in the treatment of asymptomatic bacteriuria (ASB).

OBJECTIVES

Should ASB be treated with antibiotics in immunocompromized patients, namely solid organ transplant, especially kidney transplant or stem cell transplant recipients?

MATERIALS AND METHODS

A rapid review based on a systematic literature search in MEDLINE between 1980 and 2022 was performed. For evidence synthesis, only randomized controlled trials (RCTs) or quasi-RCTs were considered.

RESULTS

No studies were identified for the search term solid organ and stem cell transplantation. Three RCTs (antibiotic therapy versus no therapy) were included for adult kidney transplantation. None of the studies showed a benefit for antibiotic therapy of ASB in reduction of symptomatic urinary tract infections, especially in the late transplantation phase two months after kidney transplantation; furthermore, this therapy may promote AMR development. In addition, there are numerous gaps of evidence, e.g., in pediatric transplantation or regarding the influence of special immunosuppressants.

CONCLUSION

There is no evidence for antibiotic therapy of ASB in adult kidney transplantation two months after the surgery. Further studies addressing the identified evidence gaps are essential for the prevention of further AMR development.

Influence of Graft Ureter Length, a Donor-Related Factor, on Urinary Tract Infections After Living-Donor Kidney Transplantation: A Single-Center Analysis of 211 Cases

Urinary tract infection (UTI) occurs in 25% of recipients of living-donor kidney transplantation (LDKT). Female sex, age, and anatomical abnormalities have been reported as recipient-related risk factors for UTI after LDKT; few studies have reported donor-related factors. We retrospectively examined UTI occurrence within 5 years of transplantation in recipients (n = 211) who underwent LDKT at our hospital between April 2011 and April 2021. All nephrectomies were performed using a retroperitoneal pure laparoscopic approach. The ureter was dissected at the lower level of the common iliac artery and trimmed to the shortest length, enough to reach the bladder using extra vesicular ureterocystoneostomy with a 3 cm submucosal tunnel. Twenty-nine recipients (13.7%) developed UTI within 5 years, and the median time to onset was 40.0 days. After adjusting for the well-known factors, including recipient sex, graft ureter length was an independent factor for UTI occurrence (HR 1.25, 95% CI 1.02∼1.53, p = 0.028) in the multivariate Cox regression analysis. The long ureter is usually trimmed, and the widest part is used for anastomosis, which may increase the possibility of reflux from the bladder to the ureter in the standard technique. The ureter length may be associated with the incidence of UTI after LDKT.

Urinary Tract Infections Caused by K. pneumoniae in Kidney Transplant Recipients – Epidemiology, Virulence and Antibiotic Resistance

Urinary tract infections are the most common complication in kidney transplant recipients, possibly resulting in the deterioration of a long-term kidney allograft function and an increased risk of recipient’s death. K. pneumoniae has emerged as one of the most prevalent etiologic agents in the context of recurrent urinary tract infections, especially with multidrug resistant strains. This paper discusses the epidemiology and risk factors associated with urinary tract infections in kidney transplant recipients, multi-drug resistance of K. pneumoniae (ESBL, KPC, NDM), treatment and pathogenesis of K. pneumoniae infections, and possible causes of recurrent UTIs. It also addresses the issue of colonization/becoming a carrier of K. pneumoniae in the gastrointestinal tract and asymptomatic bacteriuria in relation to a symptomatic UTI development and epidemiology.

Pearls and Pitfalls in Pediatric Kidney Transplantation After 5 Decades

Worldwide, over 1,300 pediatric kidney transplantations are performed every year. Since the first transplantation in 1959, healthcare has evolved dramatically. Pre-emptive transplantations with grafts from living donors have become more common. Despite a subsequent improvement in graft survival, there are still challenges to face. This study attempts to summarize how our understanding of pediatric kidney transplantation has developed and improved since its beginnings, whilst also highlighting those areas where future research should concentrate in order to help resolve as yet unanswered questions. Existing literature was compared to our own data of 411 single-center pediatric kidney transplantations between 1968 and 2020, in order to find discrepancies and allow identification of future challenges. Important issues for future care are innovations in immunosuppressive medication, improving medication adherence, careful donor selection with regard to characteristics of both donor and recipient, improvement of surgical techniques and increased attention for lower urinary tract dysfunction and voiding behavior in all patients.

Acute Allograft Pyelonephritis: Vague Symptoms, Indeterminate Laboratory Results, and the Necessity of Indication Biopsy

OBJECTIVES

In this study, we examined the clinical and biochemical features of biopsy-proven acute pyelonephritis among 769 kidney transplant recipients.

MATERIALS AND METHODS

This cohort study was performed between January 2003 and December 2019 at the University of Health Sciences (Izmir, Turkey). Acute pyelonephritis refers to urinary tract infection with acute graft dysfunction. All patients with suspected acute pyelonephritis underwent diagnostic biopsy and received antibiotic treatment for an average of 14 to 21 days. Patients with acute pyelonephritis (18/769, 2.3%) were categorized into groups of 9 patients each: group 1 developed acute pyelonephritis in the first 6 months, and group 2 developed acute pyelonephritis >6 months posttransplant.

RESULTS

All patients in group 1 had acute graft dysfunction; only 2 (22%) were symptomatic. All patients recovered baseline graft function after treatment. Patients in group 2 had at least 2 laboratory findings that included leukocytosis, neutrophilia, and high C-reactive protein values. Six patients had urine culture positivity. Recurrent pyelonephritis occurred in 3 patients. Four patients had graft loss. Over the mean follow-up of 48.0 ± 28.4 months, 14 patients (78%) were alive with a functioning graft.

CONCLUSIONS

Diagnostic biopsy is of great importance in patients with urinary tract infection accompanied by acute graft dysfunction in the first 6 months after transplant.

Urinary Tract Infections in Kidney Transplant Recipients-Is There a Need for Antibiotic Stewardship?

(1) Background: Urinary tract infections (UTI) are the most common infections after kidney transplantation. Given the risk of urosepsis and the potential threat to the graft, the threshold for treating UTI and asymptomatic bacteriuria with broad spectrum antibiotics is low. Historically fluoroquinolones were prescription favorites for patients that underwent kidney transplantation (KT). After the recent recommendation to avoid them in these patients, however, alternative treatment strategies need to be investigated (2) Methods: We retrospectively analyzed the charts of 207 consecutive adult kidney transplantations that were performed at the department of General, Visceral and Transplantation Surgery of the University Hospital of Tuebingen between January 2015 and August 2020. All charts were screened for the diagnosis and treatment of asymptomatic bacteriuria (ASB) and urinary tract infections (UTI) and the patients' clinical characteristics and outcomes were evaluated. (3) Results: Of the 207 patients, 68 patients suffered from urinary tract infections. Patients who developed UTI had worse graft function at discharge (p = 0.024) and at the 12 months follow-up (p < 0.001). The most commonly prescribed antibiotics were Ciprofloxacin and Piperacillin/Tazobactam. To both, bacterial resistance was more common in the study cohort than in the control group. (4) Conclusions: Urinary tract infections appear to be linked to worse graft functions. Thus, prevention and treatment should be accompanied by antibiotic stewardship teams.

Recurrent Urinary Tract Infections and Asymptomatic Bacteriuria in Adults

Purpose of review

Our goal was to summarize recent evidence regarding recurrent urinary tract infections and asymptomatic bacteriuria in different adult populations.

Recent findings

Several research groups are focused on the description of resident bacterial flora in the bladder and urinary dysbiosis in the microbiome era. Even the definitions might change in light of these discoveries. However, the role of urinary microbiome and bacterial interference has still to be determined.

Summary

Systematic treatment of asymptomatic bacteriuria is not recommended and even classic indications such as asymptomatic bacteriuria in pregnant women are controversial. In fact, its treatment is associated with a higher probability of symptomatic UTI and a higher prevalence of antibiotic-resistant bacteria. Improving the diagnosis of asymptomatic bacteriuria and optimizing the management of recurrent urinary tract infections, especially through non-antibiotics measures, are needed in order to minimise antimicrobial resistance.

Urinary Tract Infections in the First 6 Months after Renal Transplantation

Purpose

Urinary tract infections (UTIs) are common in the first 6 months after renal transplantation, and there are only limited data about UTIs after transplantation in Saudi Arabia in general.

Methods

A retrospective study from January 2017 to May 2020 with 6-month follow-up.

Results

279 renal transplant recipients were included. Mean age was 43.4 ± 16.0 years, and114 (40.9%) were women. Urinary stents were inserted routinely during transplantation and were removed 35.3 ± 28 days postoperatively. Ninety-seven patients (35%) developed urinary tract infections (UTIs) in the first six months after renal transplantation. Of those who developed the first episode of UTI, the recurrence rates were 57%, 27%, and 14% for having one, two, or three recurrences, respectively. Late urinary stent removals, defined as more than 21 days postoperatively, tended to have more UTIs (OR: 1.43, P: 0.259, CI: 0.76–2.66). Age >40, female gender, history of neurogenic bladder, and transplantation abroad were statistically significant factors associated with UTIs and recurrence. Diabetes, level of immunosuppression, deceased donor renal transplantation, pretransplant residual urine volume, or history of vesicoureteral reflux (VUR) was not associated with a higher incidence of UTIs. UTIs were asymptomatic in 60% but complicated with bacteremia in 6% of the cases. Multidrug resistant organisms (MDROs) were the causative organisms in 42% of cases, and in-hospital treatment was required in about 50% of cases. Norfloxacin + Bactrim DD (160/800 mg) every other day was not associated with the lower risk of developing UTIs compared to the standard prophylaxis daily Bactrim SS (80/400 mg).

Conclusion

UTIs and recurrence are common in the first 6 months after renal transplantation. Age >40, female gender, neurogenic bladder, and transplantation abroad are associated with the increased risk of UTIs and recurrence. MDROs are common causative organisms, and hospitalization is frequently required. Dual prophylactic antibiotics did not seem to be advantageous over the standard daily Bactrim.

A Current Review of the Etiology, Clinical Features, and Diagnosis of Urinary Tract Infection in Renal Transplant Patients

Urinary tract infection (UTI) represents the most common infection after kidney transplantation and remains a major cause of morbidity and mortality in kidney transplant (KT) recipients, with a potential impact on graft survival. UTIs after KT are usually caused by Gram-negative microorganisms. Other pathogens which are uncommon in the general population should be considered in KT patients, especially BK virus since an early diagnosis is necessary to improve the prognosis. UTIs following kidney transplantation are classified into acute simple cystitis, acute pyelonephritis/complicated UTI, and recurrent UTI, due to their different clinical presentation, prognosis, and management. Asymptomatic bacteriuria (ASB) represents a frequent finding after kidney transplantation, but ASB is considered to be a separate entity apart from UTI since it is not necessarily a disease state. In fact, current guidelines do not recommend routine screening and treatment of ASB in KT patients, since a beneficial effect has not been shown. Harmful effects such as the development of multidrug-resistant (MDR) bacteria and a higher incidence of Clostridium difficile diarrhea have been associated with the antibiotic treatment of ASB.

Chronic Kidney Allograft Disease: New Concepts and Opportunities

Chronic kidney disease (CKD) is increasing in most countries and kidney transplantation is the best option for those patients requiring renal replacement therapy. Therefore, there is a significant number of patients living with a functioning kidney allograft. However, progressive kidney allograft functional deterioration remains unchanged despite of major advances in the field. After the first post-transplant year, it has been estimated that this chronic allograft damage may cause a 5% graft loss per year. Most studies focused on mechanisms of kidney graft damage, especially on ischemia-reperfusion injury, alloimmunity, nephrotoxicity, infection and disease recurrence. Thus, therapeutic interventions focus on those modifiable factors associated with chronic kidney allograft disease (CKaD). There are strategies to reduce ischemia-reperfusion injury, to improve the immunologic risk stratification and monitoring, to reduce calcineurin-inhibitor exposure and to identify recurrence of primary renal disease early. On the other hand, control of risk factors for chronic disease progression are particularly relevant as kidney transplantation is inherently associated with renal mass reduction. However, despite progress in pathophysiology and interventions, clinical advances in terms of long-term kidney allograft survival have been subtle. New approaches are needed and probably a holistic view can help. Chronic kidney allograft deterioration is probably the consequence of damage from various etiologies but can be attenuated by kidney repair mechanisms. Thus, besides immunological and other mechanisms of damage, the intrinsic repair kidney graft capacity should be considered to generate new hypothesis and potential therapeutic targets. In this review, the critical risk factors that define CKaD will be discussed but also how the renal mechanisms of regeneration could contribute to a change chronic kidney allograft disease paradigm.

Asymptomatic Bacteriuria in Post Renal Transplant Patients: To Treat or Not?

Urinary tract infections (UTIs) can commonly occur within the first few weeks following kidney transplantation procedures. Although the management of asymptomatic bacteriuria and acute graft pyelonephritis is important to reduce the risk of graft rejections following kidney transplantation, the efficacy of antibiotics administration remains controversial among studies in the literature. The aim of this review is to elaborate more on asymptomatic bacteriuria following kidney transplantation and try to formulate proper evidence about the efficacy of antibiotics administration on eliminating the frequency of infections and enhancing the quality of care for patients. Most studies in the literature are observational, which are usually biased in the interventions. However, the current evidence regarding the management and screening of asymptomatic bacteriuria seems to discourage such an approach. Almost all of the included studies reported that antibiotic administration did not significantly lower the rates of secondary symptomatic UTIs or enhance the functions of the graft. In addition, there is no significant impact on mortality and other clinical outcomes. Lastly, the frequent administration of antibiotics can significantly increase the risk of recurrence due to the emergence of novel strains of bacteria that are resistant to the currently administered antibiotics making it unfavorable.

Perioperative fosfomycin disodium prophylaxis against urinary tract infection in renal transplant recipients: a randomized clinical trial

Background

Symptomatic urinary tract infection (UTI) is the most common infectious complication in renal transplant recipients (RTRs). Fosfomycin (FOS) is an attractive alternative for prophylaxis because it does not interact with immunosuppressants; although 90% is excreted unchanged in the urine, it does not require adjustment for renal function for single dose prophylaxis.

Methods

RTRs were recruited into this randomized, double-blind, placebo-controlled trial. Participants were randomized (1:1) to receive one 4 g dose of FOS disodium intravenously 3 h (FOS group) or placebo (placebo group) before placement and removal of a urinary catheter and before removal of a double-J ureteral stent. All participants received prophylaxis with trimethoprim/sulfamethoxazole. The main outcome was a comparison of the mean number of symptomatic UTI and asymptomatic bacteriuria (AB) episodes per patient during a 7-week follow-up period. The study was registered at ClinicalTrials.gov, NTC03235947.

Results

Eighty-two participants were included (41 in the FOS group and 41 in placebo group). The mean number of AB or symptomatic UTI episodes per patient was lower in the FOS group [intention-to-treat (ITT) 0.29 versus 0.60, P = 0.04]. The incidence of symptomatic UTI was lower in the FOS group (ITT, 7.3% versus 36.6%, P = 0.001), and there was no difference in the incidence of AB between both groups. The incidence of adverse events was similar in both groups.

Conclusions

FOS addition is an effective and safe strategy to reduce the number of symptomatic UTIs during the first 7 weeks after renal transplant.

Predictive factors and management of urinary tract infections after kidney transplantation: a retrospective cohort study

BACKGROUND

Urinary tract infection (UTI) is one of the most common infectious complications in kidney transplant recipients. The aims of our study were to identify possible predictive factors for UTI and advocate for the management of UTI after kidney transplantation (KT).

METHODS

Between January 2013 and December 2018, 182 adult patients with end-stage kidney disease who underwent KT were retrospectively analyzed. Patients who had urinary symptoms and positive urine culture were diagnosed with UTI. The types of urinary bacteria causing UTIs were also examined.

RESULTS

UTIs occurred in forty-one patients (25.1%), and the median time to UTI onset (UTI-free survival) after KT was 189 days. The Cox hazard regression analysis showed that the predictive factors for UTI onset were as follows: posttransplant urinary catheterization, including indwelling urinary catheterization and clean intermittent catheterization; a maximum bladder capacity before KT of less than 150 ml; and a low serum albumin level at 1 month after KT. The most common causative agent was Escherichia coli (56.6%), followed by Enterococcus spp. (15.6%) and Klebsiella spp.

CONCLUSIONS

Kidney transplant recipients with prolonged postoperative malnutrition, posttransplant voiding dysfunction and/or urinary storage disorder had an increased risk of UTI. Bladder function tests, such as uroflowmetry, postvoid residual urine tests, and urodynamic tests, were needed to predict UTI. For patients with malnutrition, care should be taken to ensure sufficient calorie intake. Kidney transplant recipients who develop UTI should be treated as complicated UTI patients.

How to Treat Asymptomatic and Symptomatic Urinary Tract Infections in the Kidney Transplant Recipients?

Patients with end-stage renal functions are treated with renal transplantation. After the transplantation, kidney transplant recipients (KTR) are at the risk of urinary tract infection (UTI). UTI in KTR may be symptomatic and asymptomatic. Asymptomatic UTI is the presence of the organisms without any signs and symptoms. There are various ways suggested in the published research papers to deal with UTI in the KTR. The goal of this literature review is to explore how to treat symptomatic and asymptomatic UTI in KTR. A PubMed search was conducted to identify the studies explaining the methods used to deal with UTI in KTR. A total number of 2158 articles were found while searching for regular keywords; however, we found 996 articles with the medical subject heading (Mesh) keywords. After applying the inclusion/ exclusion criteria, 56 articles with the regular keywords search and 29 articles with the Mesh keywords search were selected. These articles included 24 randomized clinical trials, 16 clinical trials, 7 review articles, 5 case reports, 2 controlled clinical trials, 2 observational studies, and 1 cross-sectional study. Our analysis has shown that the early removal of the stent after the transplantation and the use of antibiotics are beneficial in reducing the incidence of symptomatic UTI in the KTR; whereas, treating asymptomatic UTI in KTR has not been proven helpful in reducing the incidence of developing symptomatic UTI later on.

Post-Antibiotic Effect of Ampicillin and Levofloxacin to Escherichia coli and Staphylococcus aureus Based on Microscopic Imaging Analysis

Post-antibiotic effect (PAE) is the continued suppression of bacterial growth following a limited exposure to an antimicrobial agent. The presence of PAE needs consequential consideration in designing antibiotic dosage regimens. To understand the behavior of bacteria, PAE provides information on how long antibiotics are applied to the bacteria. Conventional methods of measuring PAE depend on population detection and have limitations for understanding the individual behavior of bacteria. To observe the PAE, we utilized an imaging technique with the use of microscopy. Here, we discuss the microscopic image analysis system we used to study the PAE at a single-colony level. The size and number of colonies of bacteria were measured prior to and following antibiotic removal. We could count a single colony, see the development of the settlement prior to and following exposure of antibiotics and track the colony by microscopy according to the incubation time and the image processed by our own image processing program. The PAE of antibiotics was quantified by comparing bacteria size and number based on their exposure time. In our study, we discovered that the longer exposure of antibiotics causes the bacteria to be suppressed—even after washing the antibiotics from the solution. This finding suggests that microscopic imaging detection provides a new method for understanding PAE. In addition, the behavior of the cell in response to drugs and chemicals and their removal can be examined with the use of single colony analysis.

Analysis of Susceptibility to Selected Antibiotics in Klebsiella pneumoniae, Escherichia coli, Enterococcus faecalis and Enterococcus faecium Causing Urinary Tract Infections in Kidney Transplant Recipients over 8 Years: Single-Center Study

Background: Urinary tract infections (UTIs) are the most common bacterial infections among kidney transplant (KTX) recipients. The purpose of this study was to analyze antimicrobial resistance (AMR) in four most common pathogens responsible for UTIs in KTX recipients and determine risk factors (RF) for resistance in the same group. Methods: Analyzed antibiograms were based on urine samples positive for bacterial growth of 10⁵ colony-forming units (CFU)/mL obtained from hospitalized adult KTX recipients presenting with UTI symptoms upon admission to the center in years 2011–2018. Results: In total, 783 antibiograms were analyzed for Klebsiella pneumoniae (258 samples, 33.0%), Escherichia coli (212, 27.0%), Enterococcus faecalis (128, 24.0%), and Enterococcus faecium (125, 16.0%). The decrease in susceptibility of E. coli to amoxicillin/clavulanic acid (62.9% vs. 40.0%) and ciprofloxacin (100% to 40.0%) was observed. Susceptibility to gentamicin increased from 33.3% to 92.9% in E. faecium. Susceptibility to tigecycline remained 100% through all years in case of E. faecalis and E. faecium. Male gender was a RF for resistance to amoxicillin/clavulanic acid (p = 0.008), ciprofloxacin (p = 0.0003), trimethoprim/sulfamethoxazole (p = 0.00009), ceftriaxone (p = 0.0001), and cefuroxime axetil (p = 0.00038) in K. pneumoniae and against gentamicin in E. faecalis (p = 0.015). Higher resistance to ampicillin in E. faecalis (p = 0.012) and to ciprofloxacin (p = 0.0003), trimethoprim/sulfamethoxazole (p = 0.007), piperacillin/tazobactam (p = 0.003), ceftriaxone (p = 0.001), and cefuroxime axetil (p = 0.013) in K. pneumoniae was observed in higher age groups of patients. Diabetes as a cause of kidney insufficiency (p = 0.026) and kidney-pancreas transplantation (p = 0.014) was RF for resistance to ceftriaxone in K. pneumoniae. Conclusions: AMR in uropathogens from KTX recipients fluctuated. There were identifiable RFs for resistance in the examined bacteria–antibiotic combinations. We recommend continuous mapping of site-specific microorganisms as etiology and susceptibility may vary between institutions and over time.

The effect of antibiotics on the gut microbiome: a metagenomics analysis of microbial shift and gut antibiotic resistance in antibiotic treated mice

Background

Emergence of antibiotic resistance is a global public health concern. The relationships between antibiotic use, the gut community composition, normal physiology and metabolism, and individual and public health are still being defined. Shifts in composition of bacteria, antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) after antibiotic treatment are not well-understood.

Methods

This project used next-generation sequencing, custom-built metagenomics pipeline and differential abundance analysis to study the effect of antibiotic monotherapy on resistome and taxonomic composition in the gut of Balb/c mice infected with E. coli via transurethral catheterization to investigate the evolution and emergence of antibiotic resistance.

Results

There is a longitudinal decrease of gut microbiota diversity after antibiotic treatment. Various ARGs are enriched within the gut microbiota despite an overall reduction of the diversity and total amount of bacteria after antibiotic treatment. Sometimes treatment with a specific class of antibiotics selected for ARGs that resist antibiotics of a completely different class (e.g. treatment of ciprofloxacin or fosfomycin selected for cepA that resists ampicillin). Relative abundance of some MGEs increased substantially after antibiotic treatment (e.g. transposases in the ciprofloxacin group).

Conclusions

Antibiotic treatment caused a remarkable reduction in diversity of gut bacterial microbiota but enrichment of certain types of ARGs and MGEs. These results demonstrate an emergence of cross-resistance as well as a profound change in the gut resistome following oral treatment of antibiotics.

Differentiating Asymptomatic Bacteriuria From Urinary Tract Infection in the Pediatric Neurogenic Bladder Population: NGAL As a Promising Biomarker

Objective: To evaluate whether urinary antimicrobial peptides (AMPs) can discriminate between asymptomatic bacteriuria (ASB) and urinary tract infection (UTI) in pediatric patients with neurogenic bladder (NGB). Design/Methods: Bladder urine was collected from pediatric patients (≤18 years old) with NGB without augmentation cystoplasty. Patients were divided into the following groups based on symptomatology and results of urinalysis/urine culture: (a) UTI, (b) ASB, and (c) sterile. Urine AMPs β defense 1 (BD-1), neutrophil gelatinase-associated lipocalin (NGAL), cathelicidin (LL-37), hepatocarcinoma-intestine-pancreas/pancreatitis-associated protein (HIP/PAP), and human α defensin 5 (HD-5) were compared between groups by enzyme-linked immunosorbent assays. In addition, urines from pediatric controls without NGB or UTI were also analyzed. Significance was determined using Student's t test for parametric or Mann-Whitney U test for nonparametric data. A p value of <.05 was considered significant. Results: Thirty-six patients with NGB from a spinal dysraphism were evaluated: UTI, n = 6; ASB, n = 18; sterile, n = 12. These groups did not differ significantly by age but did significantly differ by gender (p = .0139). NGAL significantly differed between UTI and ASB groups (median 38.5 ng/mg vs 15.5 ng/mg, respectively; p = .0197) with a sensitivity and specificity of 82.4% and 83.3%, respectively. HIP/PAP, BD-1, HD-5, LL-37, and NGAL levels were all significantly higher in sterile NGB urines compared to 17 non-NGB pediatric controls (p < .0001, p = .0020, p = .0035, p = .0006, and p = .0339, respectively). Conclusion: All five urinary AMPs evaluated were significantly elevated in NGB patients compared to controls. NGAL levels may help differentiate between UTI and ASB in pediatric NGB patients.

Prevalence of asymptomatic bacteriuria among kidney transplant recipients beyond two months post-transplant: A multicenter, prospective, cross-sectional study

BACKGROUND

During routine post-kidney transplant care, most European transplant physicians screen patients for asymptomatic bacteriuria. The usefulness of this strategy is debated. To make screening cost-effective, asymptomatic bacteriuria should be prevalent enough to justify the expense, and antibiotics should improve patient outcomes significantly if asymptomatic bacteriuria is detected. Regrettably, the prevalence of asymptomatic bacteriuria among kidney transplant recipients is not well defined.

METHODS

To determine the prevalence of asymptomatic bacteriuria among kidney transplant recipients, we did a cross-sectional study among kidney transplant recipients undergoing routine surveillance in three outpatient transplant clinics in Belgium and France. We excluded patients who were in the first two months post-transplantation and/or had a urinary catheter. Asymptomatic participants who had a urine culture with one organism isolated at ≥ 105 CFU/mL were asked to provide a confirmatory urine specimen. Asymptomatic bacteriuria was defined per Infectious Diseases Society of America guidelines.

RESULTS

We screened 500 consecutive kidney transplant recipients. Overall, the prevalence of asymptomatic bacteriuria was 3.4% (17/500 patients). It was similarly low among kidney transplant recipients who were between 2 and 12 months after transplantation (1.3%, 1/76 patients) and those who were farther after transplantation (3.8%, 16/424 patients: p = 0.49). Asymptomatic bacteriuria was significantly associated with female gender (risk ratio 3.7, 95% CI 1.3-10.3, p = 0.007) and older age (mean age: 61 ± 12 years [bacteriuric participants], versus 53 ± 15 years [non-bacteriuric participants], p = 0.03). One participant's colistin-resistant Escherichia coli isolate carried the globally disseminated mcr-1 gene.

CONCLUSIONS

Among kidney transplant recipients who are beyond the second month post-transplant, the prevalence of asymptomatic bacteriuria is low. Further studies are needed to ascertain the cost-effectiveness of a screen-and-treat strategy for asymptomatic bacteriuria in this 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.

Antibiotic Treatment Versus No Treatment for Asymptomatic Bacteriuria in Kidney Transplant Recipients: A Multicenter Randomized Trial

Background

Whether antibiotic treatment of asymptomatic bacteriuria (AB) can prevent acute graft pyelonephritis (AGP) in kidney transplant (KT) recipients has not been elucidated.

Methods

In this multicenter, open-label, nonblinded, prospective, noninferiority, randomized controlled trial, we compared antibiotic treatment with no treatment for AB in KT recipients in the first year after transplantation when urinary catheters had been removed. The primary endpoint was the occurrence of AGP. Secondary endpoints included bacteremic AGP, cystitis, susceptibility of urine isolates, graft rejection, graft function, graft loss, opportunistic infections, need for hospitalization, and mortality.

Results

We enrolled 205 KT recipients between 2013 and 2015. AB occurred in 41 (42.3%) and 46 (50.5%) patients in the treatment and no treatment groups, respectively. There were no differences in the primary endpoint in the intention-to-treat population (12.2% [5 of 41] in the treatment group vs 8.7% [4 of 46] in the no treatment group; risk ratio, 1.40; 95% confidence interval, 0.40–4.87) or the per-protocol population (13.8% [4 of 29] in the treatment group vs 6.7% [3 of 45] in the no treatment group; risk ratio, 2.07, 95% confidence interval, 0.50–8.58). No differences were found in secondary endpoints, except for antibiotic susceptibility. Fosfomycin (P = .030), amoxicillin-clavulanic (P < .001) resistance, and extended-spectrum β-lactamase production (P = .044) were more common in KT recipients receiving antibiotic treatment for AB.

Conclusions

Antibiotic treatment of AB was not useful to prevent AGP in KT recipients and may increase antibiotic resistance. However, our findings should be regarded with caution, due to the small sample size analyzed.

Early Versus Delayed Double J Stent Removal in Deceased Donor Renal Transplant Recipients: A Prospective Comparative Study

Introduction: Prophylactic ureteric stents have been commonly employed to reduce the incidence of ureteric obstruction and anastomotic leaks following renal transplantation. There are very few studies on the duration of ureteric stenting in deceased donor renal transplantation (DDRT). We performed a prospective study to compare early and late double J stent removal in DDRT.

Aims and methods: The aim of this study was to compare the early and delayed removal of ureteric stents after DDRT. We performed 80 DDRTs at our center from August 2012 to December 2016, which were included in the study. However, we enrolled 48 patients as the remaining had to be excluded based on the high-risk factors. The recipients were allocated on the 14th postoperative day to two groups. Group 1 underwent early stent removal on the fourteenth postoperative day and in group 2, the stent was removed in the sixth postoperative week. The two groups were followed up for six months and the incidence of urological complications and urinary tract infections (UTI) was compared.

Results: The incidence of UTI during the follow-up period of six months was significantly lower in the early stent removal group (two out of 24) than in delayed stent removal group (eight out of 24) (p=0.016). Asymptomatic bacteriuria occurred in six out of 24 (25%) in group 1 and 10 out of 24 (41.6%) in group 2 (p=0.120). There was no significant difference in the incidence of urinary leak, hematuria, or ureteric obstruction between the two groups (p=0.900). However, stent-related symptoms were significantly more in the delayed stent removal group (three in group 1 versus 18 in group 2) (p=0.001).

Conclusion: Prolonged stenting is associated with an increased risk of UTI and stent-related symptoms in immunosuppressed renal transplant recipients. The early removal of double J stents can be done in carefully selected patients to reduce stent-related complications in DDRT.

Antibiotics for asymptomatic bacteriuria in kidney transplant recipients

BACKGROUND

Asymptomatic bacteriuria, defined as bacteriuria without signs or symptoms of urinary tract infection (UTI), occurs in 17% to 51% of kidney transplant recipients and is thought to increase the risk for a subsequent UTI. No consensus exists on the role of antibiotics for asymptomatic bacteriuria in kidney transplantation.

OBJECTIVES

To assess the benefits and harms of treating asymptomatic bacteriuria in kidney transplant recipients with antimicrobial agents to prevent symptomatic UTI, all-cause mortality and the indirect effects of UTI (acute rejection, graft loss, worsening of graft function).

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 1 September 2017 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs in any language assessing treatment of asymptomatic bacteriuria in kidney transplant recipients at any time-point after transplantation.

DATA COLLECTION AND ANALYSIS

Two authors independently determined study eligibility, assessed quality and extracted data. Primary outcomes were incidence of symptomatic UTI and incidence of antimicrobial resistance. Other outcomes included incidences of all-cause mortality, graft loss, graft rejection, graft function, hospitalisation for UTI, adverse reactions to antimicrobial agents and relapse or persistence of asymptomatic bacteriuria. We expressed dichotomous outcomes as absolute risk difference (RD) or risk ratio (RR) with 95% confidence intervals (CI) and continuous data as mean differences (MD) with 95% CI. Data were pooled using the random effects model.

MAIN RESULTS

We included two studies (212 participants) comparing antibiotics versus no treatment, and identified three on-going studies. Overall, incidence of symptomatic UTI varied between 19% and 31% in the groups not treated for asymptomatic bacteriuria. Antibiotic treatment had uncertain effects on preventing symptomatic UTI (2 studies, 200 participants: RR 0.86, 95% CI 0.51 to 1.45). Risk for selecting multidrug-resistant organisms was uncertain with antibiotic treatment (1 study, 112 participants: RR 1.21, 95% CI 0.60 to 2.41). Persistence of asymptomatic bacteriuria was high regardless of treatment. Antibiotics also have uncertain effects on other important patient and graft outcomes, for instance on all-cause mortality (1 study, 112 participants: RR 2.23, 95% CI 0.21 to 23.86), graft loss (1 study, 112 participants: RR 1.11, 95% CI 0.07 to 17.36), acute rejection (1 study, 112 participants: RR 0.93, 95% CI 0.44 to 1.97), hospitalisation for UTI (1 study, 112 participants: RR 0.74, 95% CI 0.13 to 4.27), graft function (2 studies, 200 participants, MD in serum creatinine concentration -0.06 mg/dL, 95% CI -0.19 to 0.08) and adverse reactions (1 study, 112 participants: no severe adverse event attributable to the antibiotic treatment). Evidence quality was low for all outcomes.

AUTHORS' CONCLUSIONS

Currently, there is insufficient evidence to support routinely treating kidney transplant recipients with antibiotics in case of asymptomatic bacteriuria after transplantation, but data are scarce. Further studies assessing routine antibiotic treatment would inform practice and we await the results of three ongoing randomised studies, which may help resolve existing uncertainties.