Incidence and risk factors for diarrhea following kidney transplantation and association with graft loss and mortality

Management of kidney transplant recipients for primary care practitioners

Patients with kidney transplants have a significant co-morbidity index, due to a high number of pre-existing conditions and use of immunosuppression medications. These patients are at higher risk of developing conditions such as hypertension, dyslipidemia, post-transplant diabetes, cardiovascular events, and anemia. Moreover, they are particularly susceptible to infections such as urinary tract infections or pyelonephritis, cancers, and gastrointestinal complications such as diarrhea, which in turn may be attributed to medication adverse effects or infectious causes. Along with these concerns, meticulous management of electrolytes and allograft function is essential. Prior to prescribing any new medications, it is imperative to exercise caution in identifying potential interactions with immunosuppression drugs. This review aims to equip primary care practitioners to address these complex issues and appropriate methods of delivering care to this rapidly growing highly susceptible group.

Diagnostic performance of a multiplexed gastrointestinal PCR panel for identifying diarrheal pathogens in children undergoing hematopoietic stem cell transplant

BACKGROUND

Diarrhea is a common complication of hematopoietic stem cell transplantation (HSCT) and is associated with substantial morbidity, but its etiology is often unknown. Etiologies of diarrhea in this population include infectious causes, chemotherapy- or medication-induced mucosal injury and graft-versus-host disease (GVHD). Distinguishing these potential causes of diarrhea is challenging since diarrheal symptoms are often multifactorial, and the etiologies often overlap in transplant patients. The objectives of this study were to evaluate whether the FilmArray gastrointestinal (GI) panel would increase diagnostic yield and the degree to which pre-transplantation colonization predicts post-transplantation infection.

METHODS

From November 2019 to February 2021, a total of 158 patients undergoing HSCT were prospectively included in the study. Stool specimens were obtained from all HSCT recipients prior to conditioning therapy, 28 ± 7 days after transplantation and at any new episode of diarrhea. All stool samples were tested by the FilmArray GI panel and other clinical microbiological assays.

RESULTS

The primary cause of post-transplantation diarrhea was infection (57/84, 67.86%), followed by medication (38/84, 45.24%) and GVHD (21/84, 25.00%). Ninety-five of 158 patients were colonized with at least one gastrointestinal pathogen before conditioning therapy, and the incidence of infectious diarrhea was significantly higher in colonized patients (47/95, 49.47%) than in non-colonized patients (10/63, 15.87%) (P < 0.001). Fourteen of 19 (73.68%) patients who were initially colonized with norovirus pre-transplantation developed a post-transplantation norovirus infection. Twenty-four of 62 (38.71%) patients colonized with Clostridium difficile developed a diarrheal infection. In addition, FilmArray GI panel testing improved the diagnostic yield by almost twofold in our study (55/92, 59.78% vs. 30/92, 32.61%).

CONCLUSIONS

Our data show that more than half of pediatric patients who were admitted for HSCT were colonized with various gastrointestinal pathogens, and more than one-third of these pathogens were associated with post-transplantation diarrhea. In addition, the FilmArray GI panel can increase the detection rate of diarrheal pathogens in pediatric HSCT patients, but the panel needs to be optimized for pathogen species, and further studies assessing its clinical impact and cost-effectiveness in this specific patient population are also needed.

Pharmacomicrobiomics: Immunosuppressive Drugs and Microbiome Interactions in Transplantation

The human microbiome is associated with human health and disease. Exogenous compounds, including pharmaceutical products, are also known to be affected by the microbiome, and this discovery has led to the field of pharmacomicobiomics. The microbiome can also alter drug pharmacokinetics and pharmacodynamics, possibly resulting in side effects, toxicities, and unanticipated disease response. Microbiome-mediated effects are referred to as drug-microbiome interactions (DMI). Rapid advances in the field of pharmacomicrobiomics have been driven by the availability of efficient bacterial genome sequencing methods and new computational and bioinformatics tools. The success of fecal microbiota transplantation for recurrent Clostridioides difficile has fueled enthusiasm and research in the field. This review focuses on the pharmacomicrobiome in transplantation. Alterations in the microbiome in transplant recipients are well documented, largely because of prophylactic antibiotic use, and the potential for DMI is high. There is evidence that the gut microbiome may alter the pharmacokinetic disposition of tacrolimus and result in microbiome-specific tacrolimus metabolites. The gut microbiome also impacts the enterohepatic recirculation of mycophenolate, resulting in substantial changes in pharmacokinetic disposition and systemic exposure. The mechanisms of these DMI and the specific bacteria or communities of bacteria are under investigation. There are little or no human DMI data for cyclosporine A, corticosteroids, and sirolimus. The available evidence in transplantation is limited and driven by small studies of heterogeneous designs. Larger clinical studies are needed, but the potential for future clinical application of the pharmacomicrobiome in avoiding poor outcomes is high.

Physical Exercise After Solid Organ Transplantation: A Cautionary Tale

An increasing body of randomized controlled trials suggests the safety of engaging in moderate to vigorous intensity exercise training following solid organ transplantation. Fueled by emerging sport events designed for transplant recipients and the ever-growing body of research highlighting the diverse health benefits of physical activity, transplant recipients are now increasingly participating in strenuous and occasionally competitive physical endeavors that largely surpass those evaluated in controlled research settings. This viewpoint article adopts a cautionary stance to counterbalance the prevalent one-sided optimistic perspective regarding posttransplant physical activity. While discussing methodological limitations, we explore plausible adverse impacts on the cardiovascular, immunological, and musculoskeletal systems. We also examine the physiological consequences of exercising in the heat, at high altitude, and in areas with high air pollution. Risks associated with employing performance-enhancing strategies and the conceivable psychological implications regarding physical activity as a tribute to the 'gift of life' are discussed. With a deliberate focus on the potential adverse outcomes of strenuous posttransplant physical activity, this viewpoint aims to restore a balanced dialogue on our comprehension of both beneficial and potentially detrimental outcomes of physical activity that ultimately underscores the imperative of well-informed decision-making and tailored exercise regimens in the realm of posttransplant care.

Management of de novo nephrolithiasis after kidney transplantation: a comprehensive review from the European Renal Association CKD-MBD working group

The lifetime incidence of kidney stones is 6%-12% in the general population. Nephrolithiasis is a known cause of acute and chronic kidney injury, mediated via obstructive uropathy or crystal-induced nephropathy, and several modifiable and non-modifiable genetic and lifestyle causes have been described. Evidence for epidemiology and management of nephrolithiasis after kidney transplantation is limited by a low number of publications, small study sizes and short observational periods. Denervation of the kidney and ureter graft greatly reduces symptomatology of kidney stones in transplant recipients, which may contribute to a considerable underdiagnosis. Thus, reported prevalence rates of 1%-2% after kidney transplantation and the lack of adverse effects on allograft function and survival should be interpreted with caution. In this narrative review we summarize current state-of-the-art knowledge regarding epidemiology, clinical presentation, diagnosis, prevention and therapy of nephrolithiasis after kidney transplantation, including management of asymptomatic stone disease in kidney donors. Our aim is to strengthen clinical nephrologists who treat kidney transplant recipients in informed decision-making regarding management of kidney stones. Available evidence, supporting both surgical and medical treatment and prevention of kidney stones, is presented and critically discussed. The specific anatomy of the transplanted kidney and urinary tract requires deviation from established interventional approaches for nephrolithiasis in native kidneys. Also, pharmacological and lifestyle changes may need adaptation to the specific situation of kidney transplant recipients. Finally, we point out current knowledge gaps and the need for additional evidence from future studies.

Analysis of risk factors and prognosis of diarrhea after renal transplantation

BACKGROUND

Diarrhea is a prevalent complication after renal transplantation.

OBJECTIVE

To examine the risk factors for diarrhea after renal transplantation, evaluate their combined predictive values, and analyze the prognosis.

METHODS

Clinical data of patients who underwent allogeneic renal transplantation in the Second People's Hospital of Shanxi Province from January 2019 to March 2020 were retrospectively analyzed, cases were screened and grouped, independent risk factors for diarrhea after renal transplantation were analyzed by univariate analysis and multivariate analysis, and their predictive value was evaluated by receiver operating characteristic (ROC) curve. The survival time of recipient grafts in diarrhea and non-diarrhea groups were evaluated by Kaplan-Meier and log-rank test.

RESULTS

We included 166 recipients in the study and the incidence of diarrhea was 25.9%; univariate and logistic regression multivariate analyses revealed that independent risk factors for diarrhea in recipients were that the type of renal transplant donor was DCD (donation after circulatory death), immunity induction was onducted with basiliximab + antithymocyte globulin (ATG), and ATG alone, the type of mycophenolic acid (MPA) used was mycophenolate mofetil capsules, and delayed graft function (DGF) occurred after transplantation. The ROC curve indicated that the combination of the four factors had good accuracy in predicting the occurrence of diarrhea in recipients. The graft survival rate two years after the operation in the diarrhea group was significantly lower than that in the non-diarrhea group.

CONCLUSION

Diarrhea affected the two-year survival rate of the graft. The type of donor, immunity induction scheme, and the type of MPA and DGF were independent risk factors for diarrhea in recipients, and the combination of the four factors had good prognostic prediction value.

Mycophenolate mofetil increases the risk of diarrhea in allogeneic hematopoietic stem cell transplantation recipients

OBJECTIVES

Mycophenolate mofetil (MMF) was reported to be a main cause of diarrhea following organ transplantation. However, research on MMF-induced diarrhea following allogeneic hematopoietic stem cell transplantation (allo-HSCT) is currently insufficient. This retrospective study examined the incidence of MMF-induced diarrhea among allo-HSCT recipients.

METHODS

Recipients were divided according to the receipt of MMF and the appearance of diarrhea. The differences in clinical information, MMF usage and trough concentrations, and the occurrence of diarrhea from the first day of conditioning treatment to 100 days after transplantation were analyzed.

RESULTS

In total, 32.9% of the recipients reported diarrhea. The incidence rate of diarrhea was higher in the MMF group than in the non-MMF group (40.0% vs. 16.7%). MMF-induced diarrhea usually occurred within 9 days of MMF initiation and persisted for 7.27 ± 3.54 days. The average body weight, MMF daily dose, and MMF trough concentration were higher in patients with diarrhea.

CONCLUSION

MMF increased the risk of diarrhea in allo-HSCT recipients, and the risk was related to the MMF dose and trough concentration. The difference in onset time could be a basis for identifying the cause of diarrhea in allo-HSCT recipients.

Diarrhea after kidney transplantation: A study of risk factors and outcomes

Background

Diarrhea in kidney transplant recipients (KTRs) can be associated with significant morbidity.

Material and Methods

We evaluated 198 KTRs for a history of diarrhea post-kidney transplant at a tertiary care center in western India over 1 year. A protocol-based evaluation of diarrhea was done with respect to clinical features, diagnostic evaluation, associated acute allograft dysfunction, and its impact on long-term allograft function. Primary outcomes of interest were: chronic allograft injury (CAI) and the need for mycophenolate mofetil (MMF) withdrawal. We also assessed the effect of MMF withdrawal on the risk of the development of CAI.

Results

Eighty-five of 198 (42.5%) recipients experienced diarrhea and a total of 140 diarrheal episodes were evaluated. The mean age of these 85 recipients was 38 ± 12 years and 72 (84.7%) were males. 73 of 85 recipients were on MMF at the time of diarrhea and in 35 (48%) of them MMF withdrawal was needed for chronic and persistent symptoms. Diarrhea was attributed to infective etiologies in 90 of 140 (64.2%) cases. Among the microbiologically confirmed infective diarrheal episodes, giardia and cryptosporidium were the common pathogens in 11/28 (39%) and 6/28 (21.4%) episodes respectively. One hundred and twenty-eight episodes out of 140 (91.4%) episodes were complicated by acute allograft dysfunction. Forty-one of 85 recipients (48.2%) developed chronic allograft injury and 12 (14.1%) developed allograft rejection (acute and/or chronic). Probability of chronic allograft injury was higher in those with MMF withdrawal.

Conclusion

Diarrhea post-kidney transplant adversely affects graft function, especially after MMF withdrawal.

Development of a novel UPLC-MS/MS method for the simultaneous quantification of mycophenolic mofetil, mycophenolic acid, and its major metabolites: Application to pharmacokinetic and tissue distribution study in rats

Mycophenolate mofetil (MMF) is a prodrug of mycophenolic acid (MPA) used to prevent rejection in organ transplant patients. The purpose of this study is to develop a sensitive LC-MS/MS method to simultaneously quantify MMF, MPA, and two major metabolites, mycophenolic acid-glucuronide (MPAG) and Acyl-mycophenolic acid-glucuronide (AcMPAG) and applied this method in a pharmacokinetic (PK) and tissue distribution study. A Shimadzu UHPLC system coupled to an AB Sciex QTrap 4000 mass spectrometer was used for the analysis. Protein precipitation with a mixture of methanol: acetonitrile (2:1, v:v) was used to process the plasma samples and tissue samples. Separation was achieved using an Ultra Biphenyl 5 µm column (100 × 2.1 mm) with 0.1% formic acid in water (A) and acetonitrile (B) as the mobile phases. Quantification analysis was performed under positive ionization mode using the multiple reaction monitoring (MRM) approach. The method was linear in the range of 1.22 - 1250.00 nM for all four analytes with correlation coefficient values > 0.99. The method was reproducible, with intra- and inter-day accuracy ranging from 85.0 ± 11.2-108.3 ± 6.50 for all analytes in both plasma, liver and intestine homogenates. The extraction recovery and matrix effect of plasma sample using a mixture methanol/acetonitrile (2:1, V:V) can achieve an acceptable range (<20%), but extraction recovery and matrix effect of AcMPAG decreased to 64.10 ± 15.42 in the liver and intestine homogenates. The analytes in plasma were found to be stable under bench-top, freeze-thaw, and storage conditions. The validated method was successfully applied to quantify MMF, MPA, MPAG, and AcMPAG in a rat PK study. The PK results showed MPA was the major form exposed in the plasma in rats after oral administration of MMF, but the major metabolites in the rat's tissue disposition were MPAG.

Diagnosis, Prevention, and Treatment of Infections in Kidney Transplantation

Kidney transplant often is complicated by infections in the recipient from therapy-related and patient-related risk factors. Infections in kidney transplant recipients are associated with increased morbidity, mortality, and allograft dysfunction. There is a predictable timeline after kidney transplant regarding the types of pathogens causing infections, reflecting the net state of immunosuppression. In the early post-transplant period, bacterial infections comprise two thirds of all infections, followed by viral and fungal infections. Infections occurring early after kidney transplantation are generally the result of postoperative complications. In most cases, opportunistic infections occur within 6 months after kidney transplantation. They may be caused by a new infection, a donor-derived infection, or reactivation of a latent infection. Community-acquired pneumonia, upper respiratory tract infections, urinary tract infections, and gastrointestinal infections are the most common infections in the late period after transplantation when the net immunosuppression is minimal. It is crucial to seek information on the time after transplant, reflecting the net state of immunosuppression, previous history of exposure/infections, geography, and seasonal outbreaks. It is imperative that we develop regionally specific guidelines on screening, prevention, and management of infections after kidney transplantation.

Case Report: Severe Diarrhea Caused by Cryptosporidium Diagnosed by Metagenome Next-Generation Sequencing in Blood

Background

Cryptosporidium is one of the major pathogens causing diarrhea worldwide. At present, cryptosporidiosis is difficult to prevent and control, especially in immunocompromised hosts. It may cause life-threatening diarrhea and malabsorption among children and immunocompromised patients. Therefore, it is very important to explore rapid diagnostic tools and treatment methods for Cryptosporidium infection.

Case Presentation

We reported a case of severe diarrhea caused by cryptosporidiosis in a liver transplant recipient, whose condition was finally confirmed by metagenomic next-generation sequencing (mNGS) and fecal microscopy. His illness was resolved with immunosuppression regulation, nitazoxanide administration, and infection control.

Conclusion

So far, nitazoxanide is still the first choice for the treatment of cryptosporidiosis. Our institutional experience suggested that nitazoxanide alone may be effective on the basis of adjusting immunosuppressant. In addition, even though diagnosis of Cryptosporidium infection is a challenge, mNGS can serve as a rapid screening tool in low-prevalence setting.

Exploring a Complex Interplay: Kidney-Gut Axis in Pediatric Chronic Kidney Disease

The human intestinal microbiota is a highly intricate structure with a crucial role in promoting health and preventing disease. It consists of diverse microbial communities that inhabit the gut and contribute to essential functions such as food digestion, nutrient synthesis, and immune system development. The composition and function of the gut microbiota are influenced by a variety of factors, including diet, host genetics, and environmental features. In pediatric patients, the gut microbiota is particularly dynamic and vulnerable to disruption from endogenous and exogenous factors. Recent research has focused on understanding the interaction between the gut and kidneys. In individuals with chronic kidney disease, there is often a significant disturbance in the gut microbiota. This imbalance can be attributed to factors like increased levels of harmful toxins from the gut entering the bloodstream, inflammation, and oxidative stress. This review looks at what is known about the link between a child's gut-kidney axis, how dysbiosis, or an imbalance in the microbiome, affects chronic kidney disease, and what treatments, both pharmaceutical and non-pharmaceutical, are available for this condition.

Regulation of gut microbiota: a novel pretreatment for complications in patients who have undergone kidney transplantation

Kidney transplantation is an effective method to improve the condition of patients with end-stage renal disease. The gut microbiota significantly affects the immune system and can be used as an influencing factor to change the prognoses of patients who have undergone kidney transplantation. Recipients after kidney transplantation showed a lower abundance of Firmicutes and Faecalibacterium prausnitzii and a higher proportion of Bacteroidetes and Proteobacteria. After using prebiotics, synbiotics, and fecal microbiota transplantation to regulate the microbial community, the prognoses of patients who underwent kidney transplantation evidently improved. We aimed to determine the relationship between gut microbiota and various postoperative complications inpatients who have undergone kidney transplantation in recent years and to explore how gut microecology affects post-transplant complications. An in-depth understanding of the specific functions of gut microbiota and identification of the actual pathogenic flora during complications in patients undergoing kidney transplantation can help physicians develop strategies to restore the normal intestinal microbiome of transplant patients to maximize their survival and improve their quality of life.

The Gut Microbiota in Kidney Transplantation: A Target for Personalized Therapy?

Kidney transplantation improves quality of life, morbidity, and mortality of patients with kidney failure. However, integrated immunosuppressive therapy required to preserve graft function is associated with the development of post-transplant complications, including infections, altered immunosuppressive metabolism, gastrointestinal toxicity, and diarrhea. The gut microbiota has emerged as a potential therapeutic target for personalizing immunosuppressive therapy and managing post-transplant complications. This review reports current evidence on gut microbial dysbiosis in kidney transplant recipients, alterations in their gut microbiota associated with kidney transplantation outcomes, and the application of gut microbiota intervention therapies in treating post-transplant complications.

Gastrointestinal symptoms and endoscopy findings after pediatric solid organ transplantation: A case series

BACKGROUND

Gastrointestinal symptoms are common among solid organ transplant (SOT) recipients. Information about colonoscopy findings after pediatric SOT is limited. This retrospective study reports endoscopy findings in a nationwide pediatric transplant recipient cohort.

METHODS

All pediatric recipients (kidney, liver, or heart) transplanted between 2010 and 2020 at our institution (n = 193) who had undergone ileocolonoscopy and upper gastrointestinal endoscopy after SOT were enrolled. Sixteen patients were identified. A meticulous search on clinical data including transplantation, gastrointestinal symptoms, endoscopy findings, and follow-up data was performed.

RESULTS

Endoscopy was performed at a median of 2.6 years (0.4-13.3) after the first transplantation (median age at SOT 1.2 years). Gastrointestinal symptoms leading to endoscopy did not differ between the different transplant groups. The leading endoscopy indications were prolonged diarrhea and anemia. PTLD was found in 8 (50%) patients. Five were histologically early PTLD lesions and three were monomorphic large B-cell PTLDs (two EBV-positive and one EBV-negative), one having previously been diagnosed with autoimmune enteropathy. One patient had EBV enteritis. De novo inflammatory bowel disease was found in one patient, eosinophilic gastroenteritis in another, and in one patient with several episodes of watery diarrhea, the histological finding was mild non-specific colitis. In four patients, the endoscopy finding remained unclear and the symptoms were suspected to be caused by infectious agents or mycophenolate.

CONCLUSIONS

PTDL with various stages is a common finding after pediatric SOT in patients with gastrointestinal symptoms. Endoscopy should be considered in transplant recipients with prolonged diarrhea, anemia, and/or abdominal pain.

Management of Hospitalized Kidney Transplant Recipients for Hospitalists and Internists

The number of kidney transplant recipients has grown incrementally over the years. These patients have a high comorbidity index and require special attention to immunosuppression management. In addition, this population has an increased risk for cardiovascular events, electrolyte abnormalities, allograft dysfunction, and infectious complications. It is vital for hospitalists and internists to understand the risks and nuances in the care of this increasingly prevalent, but also high-risk, population.

Resolution of Cryptosporidiosis in Transplant Recipients: Review of the Literature and Presentation of a Renal Transplant Patient Treated With Nitazoxanide, Azithromycin, and Rifaximin

Background

Cryptosporidium is a major cause of diarrheal disease worldwide, including chronic disease in malnourished children and patients with acquired immune deficiency syndrome. There are increasing reports of cryptosporidiosis in transplant patients, especially from middle-income countries.

Methods

The literature on treatment of cryptosporidiosis in transplant patients was reviewed and included no controlled trials but only small case series. Nitazoxanide, azithromycin, spiramycin, and combination therapies have been used, but none are consistently efficacious.

Results

We present a case of chronic diarrhea from cryptosporidiosis in a renal transplant patient. His illness resolved with decreasing immunosuppression and treatment with the 3-drug combination of nitazoxanide, azithromycin, and rifaximin.

Conclusions

Although current therapies are not reliably effective in the absence of an effective cellular immune response, combination therapies hold promise for improved responses.

Epidemiology and outcomes of medically attended and microbiologically confirmed bacterial foodborne infections in solid organ transplant recipients

Food-safety measures are recommended to solid organ transplant (SOT) recipients. However, the burden of foodborne infections in SOT recipients has not been established. We describe the epidemiology and outcomes of bacterial foodborne infections in a nationwide cohort including 4405 SOT recipients in Switzerland between 2008 and 2018. Participants were prospectively followed for a median of 4.2 years with systematic collection of data on infections, and patient and graft-related outcomes. We identified 151 episodes of microbiologically confirmed bacterial foodborne infections occurring in median 1.6 years (IQR 0.58-3.40) after transplantation (131 [88%] Campylobacter spp. and 15 [10%] non-typhoidal Salmonella). The cumulative incidence of bacterial foodborne infections was 4% (95% CI 3.4-4.8). Standardized incidence rates were 7.4 (95% CI 6.2-8.7) and 4.6 (95% CI 2.6-7.5) for Campylobacter and Salmonella infections, respectively. Invasive infection was more common with Salmonella (33.3% [5/15]) compared to Campylobacter (3.2% [4/125]; p = .001). Hospital and ICU admission rates were 47.7% (69/145) and 4.1% (6/145), respectively. A composite endpoint of acute rejection, graft loss, or death occurred within 30 days in 3.3% (5/151) of cases. In conclusion, in our cohort bacterial foodborne infections were late post-transplant infections and were associated with significant morbidity, supporting the need for implementation of food-safety recommendations.

Mycobacterium tuberculosis and Cytomegalovirus Colitis in a Renal Transplant Patient: A Case Report

Chronic diarrhea is a common reason for consultation in renal transplant patients. Cytomegalovirus infection is the cause of chronic diarrhea of infectious origin in 50% of cases, but coinfection with tuberculosis is rare. We present the case of a renal transplant patient with chronic diarrhea, with a finding of left colon colitis and positive microbiological studies in biopsy for tuberculosis and cytomegalovirus. The patient received valganciclovir and anti-tubercular treatment with adequate evolution. Immunosuppressed patients may have diarrhea secondary to opportunistic infections; therefore, an algorithm for early diagnosis and treatment is recommended.

The effect of long-term immunosuppressive therapy on gastrointestinal symptoms after kidney transplantation

OBJECTIVE

We examined the relationship between compliance with long-term immunosuppressive therapy after kidney transplantation and gastrointestinal (GI) symptoms in patients discharged from hospitals in this study.

METHOD

Our study was conducted as a descriptive study with the participation of 114 kidney transplant recipients discharged from the organ transplant center of a training and research hospital. Personal Information Form, Immunosuppressive Therapy Compliance Scale and Gastrointestinal Symptom Rating Scale were used in data collection. The data analysis was performed with IBM Statistical Package for the Social Sciences (SPSS) Statistics 25.

RESULTS

According to the findings, 47.4% of kidney transplant patients were between the ages of 46 and 64, and 80.7% of them were male. 41.2% of kidney recipients used immunosuppressive agents between 91 days and 6 months. Compliance with immunosuppressive therapy was similar in all age groups. It was determined that the recipients between the ages of 18 and 30 experienced GI symptoms the most. In terms of the predictors of GI symptoms, it was determined that mycophenolate mofetil (MMF) was effective in the development of reflux and diarrhoea, cyclosporine in the development of diarrhoea and constipation, and tacrolimus in the development of indigestion, which are (p < 0.05).

CONCLUSION

For kidney recipients to have high compliance with immunosuppressive therapy, it is of great importance that they are able to cope with GI symptoms. Our study showed that GI symptoms increase in direct proportion as the duration of immunosuppressive therapy is prolonged and the level of compliance increases. GI symptoms of kidney transplant patients should be recognized, and recipients should be helped to manage those problems.

Diarrhea in pediatric recipients of solid organ or bone marrow transplants

Diarrhea is common in adults after solid organ transplantation (SOT) and bone marrow transplantation (BMT), but data in children are limited. Therefore, we aimed to determine the incidence and etiology of pediatric early-onset diarrhea in post SOT and BMT.We reviewed children aged 6 months to 18 years who underwent liver transplantation, kidney transplantation or BMT between January 2015 and December 2019 with duration of diarrhea > 72 hours within the first 6 months after transplantation. Clinical data and diarrheal course were collected. Regression analyses were performed to define factors associated with the interested outcomes.Among 252 transplanted patients, 168 patients (66.6%) had 289 documented episodes of diarrhea. A diagnosis of 68.2% of post-transplant diarrhea remained 'indefinite'. Enteric infection in SOT and gastrointestinal acute graft-versus-host disease (GI-aGVHD) in BMT were the commonly identified etiologies. Among 182 episodes among BMT children, skin rash was more pronounced when compared the ones with diarrhea > 7 days vs ≤ 7 days (odds ratio [OR] 13.9; 95% CI 1.8, 107.6). Males were more likely to develop GI-aGVHD as compared to females (OR 8.9). We found that GI-aGVHD was more common in the ones with skin rash and the presence of white blood cells in stool examination (OR 8.4 and 3.1, respectively). Deaths occurred in 7.7%.Two-thirds of post-transplant children experienced at least one episode of early-onset diarrhea, of which the etiology mainly remains undefined. Various clinical factors of prolonged/chronic diarrhea and GI-aGVHD may help clinicians when managing these children.

Urine metabolic risk factors and outcomes of patients with kidney transplant nephrolithiasis

Background

Nephrolithiasis in allograft kidneys is rare, but this diagnosis may lead to allograft complications and patient morbidity. Previous studies that have evaluated nephrolithiasis posttransplant have focused on surgical stone management, with limited data on urine metabolic risk factors and the presence of stones after follow-up.

Methods

We retrospectively evaluated kidney transplant recipients who were diagnosed with transplant nephrolithiasis between 2009 and 2019. Computed tomography and ultrasound imaging were used to confirm stone presence.

Results

The incidence of allograft kidney stone formation was 0.86% of 6548 kidney transplant recipients. Of the 56 cases identified, 17 (30%) had a pretransplant history of nephrolithiasis. Only four (7%) patients received a known kidney stone at the time of allograft implantation. Of the 56 cases, 34 had a 24-h supersaturation study. The urine supersaturation study showed 32 patients (94%) had a urine citrate of &lt;450 mg excreted in 24 h (median 124.5 mg/24 h, reference range &gt;500 mg/24 h), along with 22 patients (61%) having a urine oxalate excretion of ≥30 mg in 24 h (median 34.4 mg/24 h, reference range &lt;30 mg/24 h). Calcium oxalate composition was most common (91% with &gt;1 supersaturation for calcium oxalate crystals), with normal median urine calcium levels (median urine calcium 103.5 mg/24 h, reference range &lt;200 mg/24 h). After a 4-year follow-up, 50% (n = 28) required surgical intervention and 43 (77%) patients continued to have evidence of transplant nephrolithiasis on imaging.

Conclusions

This is the largest study of transplant nephrolithiasis confirming that hypocitraturia and hyperoxaluria were the most significant urine metabolic risk factors associated with allograft nephrolithiasis and that hyperoxaluria was the most prevalent driver for calcium oxalate stone composition. Our study is first to show low stone-free rates at the last follow-up and a significant proportion requiring surgical intervention.

Efficacy and Safety of Switching to Azathioprine for Mycophenolate-Induced Diarrhea in Renal Transplant Recipients

BACKGROUND

Diarrhea is a common adverse effect of mycophenolate treatment in renal transplant recipients. In patients with mycophenolate-induced diarrhea, one option is to switch to mycophenolate to azathioprine. In this study, we aimed to define the safety and efficacy of switching from mycophenolate to azathioprine for mycophenolate-related diarrhea in renal transplant recipients.

METHODS

A total of 177 patients, 59 of whom were switched to azathioprine because of diarrhea and 118 of whom comprised a matched control group without diarrhea and continued mycophenolate treatment participated in this study. We analyzed the effect of switching to azathioprine from mycophenolate on amelioration of diarrhea and graft survival.

RESULTS

We observed that 89.8% of patients who switched to azathioprine because of diarrhea had improved diarrhea complaints. Patients switched to azathioprine because of diarrhea had lower glomerular filtration rates (P < .001) and higher proteinuria (P < .001) compared with the control group before the switch. Patients switched to azathioprine compared with a subgroup of 59 control patients were matched to patients switched to azathioprine in terms of baseline renal function and proteinuria in addition to demographic parameters had higher 10-year graft loss compared with patients who continued mycophenolate (P = .03). Particularly in patients with a glomerular filtration rate <30 mL/min at the time of conversion, the risk of early graft loss was high.

CONCLUSIONS

Although switching from mycophenolate to azathioprine was an effective approach to improve diarrhea, this approach is associated with increased risk of graft loss.

Exhaled Hydrogen as a Marker of Intestinal Fermentation Is Associated with Diarrhea in Kidney Transplant Recipients

Background: Diarrhea is common among kidney transplant recipients (KTR). Exhaled hydrogen (H₂) is a surrogate marker of small bowel dysbiosis, which may drive diarrhea. We studied the relationship between exhaled H₂ and diarrhea in KTR, and explored potential clinical and dietary determinants. Methods: Clinical, laboratory, and dietary data were analyzed from 424 KTR participating in the TransplantLines Biobank and Cohort Study (NCT03272841). Fasting exhaled H₂ concentration was measured using a model DP Quintron Gas Chromatograph. Diarrhea was defined as fast transit time (types 6 and 7 according to the Bristol Stool Form Scale, BSFS) of 3 or more episodes per day. We studied the association between exhaled H₂ and diarrhea with multivariable logistic regression analysis, and explored potential determinants using linear regression. Results: KTR (55.4 ± 13.2 years, 60.8% male, mean eGFR 49.8 ± 19.1 mL/min/1.73 m²) had a median exhaled H₂ of 11 (5.0–25.0) ppm. Signs of small intestinal bacterial overgrowth (exhaled H₂ ≥ 20 ppm) were present in 31.6% of the KTR, and 33.0% had diarrhea. Exhaled H₂ was associated with an increased risk of diarrhea (odds ratio 1.51, 95% confidence interval 1.07–2.14 per log₂ ppm, p = 0.02). Polysaccharide intake was independently associated with higher H₂ (std. β 0.24, p = 0.01), and a trend for an association with proton-pump inhibitor use was observed (std. β 0.16 p = 0.05). Conclusion: Higher exhaled H₂ is associated with an increased risk of diarrhea in KTR. Our findings set the stage for further studies investigating the relationship between dietary factors, small bowel dysbiosis, and diarrhea after kidney transplantation.

Gastrointestinal symptoms in HIV-positive kidney transplant candidates and recipients from an HIV-positive donor

Gastrointestinal symptoms (GIS) are common in kidney transplant candidates and recipients and may be worsened by HIV. Objective: To determine the frequency and severity of GIS in HIV-positive kidney transplant recipients from HIV-positive donors, and those waiting to receive one. A GIS rating scale (GSRS) was completed by 76 participants at baseline and at 6 months. GIS frequency was defined as having at least one symptom (GSRS > 1). Severity was indicated by the GSRS score. Transplant candidates: GIS frequency was 88.9% and 86.3% at baseline and 6 months respectively. Indigestion was the most frequent (79.6% and 66.7% at baseline and 6 months), and severe GIS (GSRS 2.3). Women reported global mean (p = 0.030) severity significantly more than men. Transplant recipients: GIS frequency was 95.2% and 76.2% at baseline and 6 months respectively. At both assessment points, indigestion occurred most frequently (85.7% and 61.9% respectively). Highest GSRS was reported for indigestion at baseline (2.33) and at 6 months (1.33). Waist circumference (WC) was positively associated with the severity of constipation GSRS. GIS are common in both groups, especially indigestions. WC in transplant recipients should be monitored.

Effectiveness of Bezlotoxumab for Prevention of Recurrent Clostridioides difficile Infection Among Transplant Recipients

Background

Bezlotoxumab significantly reduces the incidence of recurrent Clostridioides difficile infection (CDI); however, limited data are available in solid organ transplant (SOT) and hematopoietic cell transplant (HCT) recipients.

Methods

We conducted a single-center retrospective analysis comparing recurrent CDI in SOT and HCT recipients receiving standard of care alone (oral vancomycin, fidaxomicin, or metronidazole) or bezlotoxumab plus standard of care. The primary outcome was 90-day incidence of recurrent CDI, and secondary outcomes included 90-day hospital readmission, mortality, and incidence of heart failure exacerbation.

Results

Overall, 94 patients received bezlotoxumab plus standard of care (n = 38) or standard of care alone (n = 56). The mean age was 53 years; patients had a median of 3 prior Clostridioides difficile episodes and 4 risk factors for recurrent infection. Most patients were SOT recipients (76%), with median time to index CDI occurring 2.7 years after transplantation. Ninety-day recurrent CDI occurred in 16% (6/38) in the bezlotoxumab cohort compared to 29% (16/56) in the standard of care cohort (P = .13). Multivariable regression revealed that bezlotoxumab was associated with significantly lower odds of 90-day recurrent CDI (odds ratio, 0.28 [95% confidence interval, .08–.91]). There were no differences in secondary outcomes, and no heart failure exacerbations were observed.

Conclusions

In a cohort of primarily SOT recipients, bezlotoxumab was well tolerated and associated with lower odds of recurrent CDI at 90 days. Larger, prospective trials are needed to confirm these findings among SOT and HCT populations.

Discrepancy between self-perceived mycophenolic acid-associated diarrhea and stool water content after kidney transplantation

BACKGROUND

Diarrhea is a well-known side effect of mycophenolic acid (MPA) use in kidney transplant recipients (KTRs). It is unknown whether self-reported diarrhea using the Modified Transplant Symptom Occurrence and Symptom Distress Scale (MTSOSD-59R) corresponds to stool water content and how both relate to MPA usage.

METHODS

MTSOSD-59R questionnaires filled out by 700 KTRs from the TransplantLines Biobank and Cohort Study (NCT03272841) were analyzed and compared with stool water content. Stool samples (N = 345) were freeze-dried, and a water content ≥80% was considered diarrhea.

RESULTS

Self-perceived diarrhea was reported by 46%, while stool water content ≥80% was present in 23% of KTRs. MPA use was not associated with self-perceived diarrhea (odds ratio(OR) 1.32; 95% confidence interval(CI), 0.87-1.99, p = .2), while it was associated with stool water content ≥80% (OR 2.88; 95%CI, 1.41-5.89, p = .004), independent of potential confounders. Adjustment for prior MPA discontinuation because of severe diarrhea, uncovered an association between MPA use and self-perceived diarrhea (OR 1.80; 95%CI, 1.13-2.89, p = .01).

CONCLUSIONS

These results suggest that reporting bias could add to the discrepancy between both methods for diarrhea assessment. We recommend use of objective biomarkers or more extensive questionnaires which assess information on stool frequency and stool consistency, to investigate post-transplantation diarrhea.

Perioperative, short-, and long-term outcomes of gastric cancer surgery: Propensity score-matched analysis of patients with or without prior solid organ transplantation

BACKGROUND

Details of perioperative outcomes and survival after gastric cancer surgery in prior transplant recipients have received minimal research attention.

METHODS

We performed an observational cohort study using the database of 20,147 gastric cancer patients who underwent gastrectomy at a single gastric cancer center in Korea. Forty-one solid organ recipients [kidney (n = 35), liver (n = 5), or heart (n = 1)] were matched with 205 controls using propensity score matching.

RESULTS

Operation time, blood loss, and postoperative pain were similar between groups. Short-term complication rates were similar between transplantation and control groups (22.0% vs. 20.1%, P = 0.777). Transplantation group patients with stage 1 gastric cancer experienced no recurrence, while those with stage 2/3 cancer had significantly higher recurrence risk compared to the controls (P = 0.049). For patients with stage 1 cancer, the transplantation group had a significantly higher rate of non-gastric cancer-related deaths compared to the controls (19.2% vs. 1.4%, P = 0.001). For those with stage 2/3 cancer, significantly lower proportion of the transplantation group received adjuvant chemotherapy compared to the control group (26.7% vs. 80.3%, P < 0.001). The transplantation group had a higher (albeit not statistically significant) rate of gastric cancer-related deaths compared to the controls (40.0% vs. 18.0%, P = 0.087).

CONCLUSION

Transplant recipients and non-transplant recipients exhibited similar perioperative and short-term outcomes after gastric cancer surgery. From long-term outcome analyses, we suggest active surveillance for non-gastric cancer-related deaths in patients with early gastric cancer, as well as strict oncologic care in patients with advanced cancer, as effective strategies for transplant recipients.

De novo ulcerative colitis after kidney transplantation treated with infliximab

Diarrhea is a common complication in kidney transplant recipients. Common causes of diarrhea include infection, side effect from medication, rejection, and malignancy. A less common but important cause of diarrhea is de novo inflammatory bowel disease (IBD). This is unexpected, as these patients are already immunosuppressed. Herein, we present the case of a 45-year-old man with end-stage kidney disease because of focal segmental glomerulosclerosis who underwent preemptive kidney transplantation, with his mother as donor. His immunosuppressive regimen included methylprednisolone, mycophenolate mofetil, and tacrolimus. He had no episodes of graft dysfunction, rejection, or infectious events. Two and a half years post-transplantation, he developed bloody diarrhea. After excluding infections, colonoscopy was performed and revealed edematous mucosa and erythema with pigmentation, which are typical findings in ulcerative colitis. Despite therapy with 5-aminosalicylate and granulocyte monocyte apheresis, he presented with massive bloody diarrhea. We initiated infliximab, an anti-tumor necrosis factor-α (TNF-α) agent. He responded very well and achieved remission within 6 months after initiation of infliximab, while administration of the other immunosuppressants was maintained. His course was uneventful and no complications developed. Management of immunosuppressants for de novo IBD after organ transplantation is complicated, because treatment of IBD, graft function protection, and prevention of infection must be considered. Therefore, cooperation between transplantation physicians and gastroenterologists is essential during therapy.

Microbiota, renal disease and renal transplantation

Aim of this frontier review has been to highlight the role of microbiota in healthy subjects and in patients affected by renal diseases with particular reference to renal transplantation. The microbiota has a relevant role in conditioning the healthy status and the diseases. In particular gut microbiota is essential in the metabolism of food and has a relevant role for its relationship with the immune system. The indigenous microbiota in patients with chronic renal failure is completely different than that of the healthy subjects and pathobionts appear. This abnormality in microbiota composition is called dysbiosis and may cause a rapid deterioration of the renal function both for activating the immune system and producing large quantity of uremic toxins. Similarly, after renal trans-plantation the microbiota changes with the appearance of pathobionts, principally in the first period because of the assumption of immunosuppressive drugs and antibiotics. These changes may deeply interfere with the graft outcome causing acute rejection, renal infections, diarrhea, and renal interstitial fibrosis. In addition, change in the microbiota may modify the metabolism of immuno-suppressive drugs causing in some patients the need of modifying the immunosuppressant dosing. The restoration of the indigenous microbiota after transplantation is important, either to avoiding the complications that impair the normal renal graft, and because recent studies have documented the role of an indigenous microbiota in inducing tolerance towards the graft. The use of prebiotics, probiotics, smart bacteria and diet modification may restore the indigenous microbiota, but these studies are just at their beginning and more data are needed to draw definitive conclusions.

Gut microbiota profiles and fecal beta-glucuronidase activity in kidney transplant recipients with and without post-transplant diarrhea

Post-transplant diarrhea is a common complication after solid organ transplantation and is frequently attributed to the widely prescribed immunosuppressant mycophenolate mofetil (MMF). Given recent work identifying the relationship between MMF toxicity and gut bacterial β-glucuronidase activity, we evaluated the relationship between gut microbiota composition, fecal β-glucuronidase activity, and post-transplant diarrhea. We recruited 97 kidney transplant recipients and profiled the gut microbiota in 273 fecal specimens using 16S rRNA gene sequencing. We further characterized fecal β-glucuronidase activity in a subset of this cohort. Kidney transplant recipients with post-transplant diarrhea had decreased gut microbial diversity and decreased relative gut abundances of 12 genera when compared to those without post-transplant diarrhea (adjusted p value < .15, Wilcoxon rank sum test). Among the kidney transplant recipients with post-transplant diarrhea, those with higher fecal β-glucuronidase activity had a more prolonged course of diarrhea (≥7 days) compared to patients with lower fecal β-glucuronidase activity (91% vs 40%, p = .02, Fisher's exact test). Our data reveal post-transplant diarrhea as a complex phenomenon with decreased gut microbial diversity and commensal gut organisms. This study further links commensal bacterial metabolism with an important clinical outcome measure, suggesting fecal β-glucuronidase activity could be a novel biomarker for gastrointestinal-related MMF toxicity.

Diarrhea in the pediatric solid organ transplantation recipient: A multidisciplinary approach to diagnosis and management

Diarrhea in the pediatric solid organ transplantation (SOT) recipient is a frequent complaint that is associated with significant morbidity and impaired quality of life. There are limited published data regarding the specific epidemiology, diagnostic evaluation, and treatment of diarrhea after SOT in children. Pediatric SOT recipients have an increased risk of developing diarrhea because of a generalized immunosuppressed state, epidemiologic exposures, and polypharmacy. There is a need to standardize the diagnostic evaluation of diarrhea in children after SOT to facilitate an accurate diagnosis and timely treatment. Herein, we review the available published data and propose a systematic, stepwise approach to the evaluation of diarrhea in this high-risk population, focusing on timely diagnosis of both infectious and non-infectious causes, in order to provide focused management. Prospective studies are needed to better assess the true prevalence, risk factors for, etiologies, and complications of diarrhea in pediatric SOT patients that will guide optimal management. Development of effective vaccines and antiviral therapies for enteric viruses may also contribute to improved outcomes.

Etiological profile of diarrhea in solid organ transplant recipients at a tertiary care center in Southern India

BACKGROUND

Diarrhea is one of the common gastrointestinal (GI) adverse events after solid organ transplantation. Diarrhea may be caused by infectious or non-infectious etiology. The infectious etiology of diarrhea varies according to the location and duration of diarrhea. Non-infectious etiologies include drugs, inflammatory bowel disease, neoplasia. The objective of this study was to evaluate the etiological profile of diarrhea in solid organ transplant recipients presenting to a tertiary care center in Southern India.

METHODS

This was a retrospective analysis of prospectively collected data of all solid organ transplantation recipients referred to the Department of Medical Gastroenterology for evaluation of diarrhea from April 2012 till May 2014. All patients had stool evaluated by wet mount examination, modified acid fast (AFB) stain, trichrome stain, culture, and Clostridium difficile toxin assay. EDTA plasma was collected for quantitative Cytomegalovirus (CMV) detection by real-time PCR. If the diarrhea was acute (<2 wk), and no etiological agent was identified, empirical antibiotic therapy was instituted and followed up. If persistent or chronic diarrhea (>2-4 wk), endoscopic evaluation (upper GI endoscopy and/or colonoscopy with biopsies), depending on the clinical type of diarrhea was done. If no specific etiological diagnosis was established after endoscopic evaluation, breath test for SIBO and celiac serology were done. If no specific etiology was identified after the above investigations, dose of immunosuppressive drugs was reduced. If diarrhea responded to dose reduction, it was considered to be drug related.

RESULTS

Fifty-eight episodes of diarrhea occurred in 55 solid organ transplant recipients during the study period. Renal transplant recipients constituted the majority (70%). Most (79%) of patients included in the study had their transplant > 6 mo ago. Infective diarrhea was the etiology in 46%, drug-related diarrhea in 29.3%. No specific etiology was identified in 22.4% of patients. Parasites accounted for 69% of all infective diarrhea. Stool evaluation was the main investigation in establishing diagnosis in acute diarrhea. Endoscopic evaluation was required in two thirds of patients to establish diagnosis in chronic diarrhea.

CONCLUSION

GI infections and drug-related diarrhea were the common causes of diarrhea in solid organ transplant recipients. Parasites were the most common infectious etiology of diarrhea. Step-wise evaluation was able to identify the etiology in ~ 77% of patients. Overall, 98% of diarrheal episodes resolved.

Association of Circulating Trimethylamine N-Oxide and Its Dietary Determinants with the Risk of Kidney Graft Failure: Results of the TransplantLines Cohort Study

Background. Due to the critical shortage of kidneys for transplantation, the identification of modifiable factors related to graft failure is highly desirable. The role of trimethylamine-N-oxide (TMAO) in graft failure remains undetermined. Here, we investigated the clinical utility of TMAO and its dietary determinants for graft failure prediction in renal transplant recipients (RTRs). Methods. We included 448 RTRs who participated in the TransplantLines Cohort Study. Cox proportional-hazards regression analyses were performed to study the association of plasma TMAO with graft failure. Net Benefit, which is a decision analysis method, was performed to evaluate the clinical utility of TMAO and dietary information in the prediction of graft failure. Results. Among RTRs (age 52.7 ± 13.1 years; 53% males), the baseline median TMAO was 5.6 (3.0–10.2) µmol/L. In multivariable regression analysis, the most important dietary determinants of TMAO were egg intake (Std. β = 0.09 [95%CI, 0.01; 0.18]; p = 0.03), fiber intake (Std. β = −0.14 [95%CI, −0.22, −0.05]; p = 0.002), and fish and seafood intake (Std. β = 0.12 [95%CI, 0.03,0.21]; p = 0.01). After a median follow-up of 5.3 (4.5–6.0) years, graft failure was observed in 58 subjects. TMAO was associated with an increased risk of graft failure, independent of age, sex, the body mass index (BMI), blood pressure, lipids, albuminuria, and the Estimated Glomerular Filtration Rate (eGFR) (Hazard Ratio per 1-SD increase of TMAO, 1.62 (95% confidence interval (CI): 1.22; 2.14, p < 0.001)). A TMAO and dietary enhanced prediction model offered approximately double the Net Benefit compared to a previously reported, validated prediction model for future graft failure, allowing the detection of 21 RTRs per 100 RTRs tested, with no false positives versus 10 RTRs, respectively. Conclusions. A predictive model for graft failure, enriched with TMAO and its dietary determinants, yielded a higher Net Benefit compared with an already validated model. This study suggests that TMAO and its dietary determinants are associated with an increased risk of graft failure and that it is clinically meaningful.

Post-transplant colitis after kidney transplantation: clinical, endoscopic and histological features

Chronic immunosuppression may increase the risk of post-transplant infection and medication-related injury and may also be responsible for the increased risk of gastrointestinal complications in kidney transplant recipients. Differentiating the various forms of post-transplant colitis is challenging, since most have similar clinical and histological features. This study evaluated the incidence of post-transplant gastrointestinal complications during screening colonoscopy. Kidney transplant recipients undergoing a colonoscopy for any reasons in the period 2014-2018 were included. Among the 134 patients completing the colonoscopy, 74 patients (56%) had an abnormal finding: an adenoma was found in 25 patients (18.6%), while 19 patients (14.1%) had colitis. Mycophenolic acid/related colitis was the most common colitis (6%), while 7 patients (5.2%) developed a de novo inflammatory bowel disease. Patients with post-transplant colitis were younger and with shorter time from transplant compared to patients without colitis. In conclusions, immunosuppression may predispose kidney transplant recipients to an increased risk of post-transplant colitis. Diagnostic colonoscopy should be encouraged in all transplant patients with refractory diarrhea and gastrointestinal symptoms to allow a prompt diagnosis and a timely treatment, finally improving the quality of life and long-term outcomes of affected patients.

Complications of Cryptosporidium infection after pediatric liver transplantation: Diarrhea, rejection, and biliary disease

BACKGROUND

Cryptosporidium enteritis can be devastating in the immunocompromised host. In pediatric liver transplant recipients, infection may be complicated by prolonged carriage of the parasite, rejection, and biliary tree damage and fibrosis. Herein, we report on six patients and their long-term outcomes following cryptosporidiosis.

METHODS

We reviewed all cases of cryptosporidiosis in a pediatric liver transplant population over a 17-year period at a single center. Six patients with infection were identified, and their outcomes were analyzed.

RESULTS

Infection was associated with significant diarrhea and dehydration in all cases, and led to hospitalization in one-half of patients. Four of the six patients developed biopsy-proven rejection following infection, with three of those patients developing rejection that was recalcitrant to intravenous steroid treatment. Additionally, three patients developed biliary tree abnormalities with similarity to sclerosing cholangitis. In one patient, those biliary changes led to repeated need for biliary drain placement and advancing fibrotic liver allograft changes.

CONCLUSIONS

Cryptosporidiosis in pediatric liver transplant recipients may lead to significant complications, including recalcitrant episodes of rejection and detrimental biliary tree changes. We advocate for increased awareness of this cause of diarrheal disease and the allograft injuries that may accompany infection.

Emerging Microbiology Diagnostics for Transplant Infections: On the Cusp of a Paradigm Shift

In light of the heightened risk for infection associated with solid organ and hematopoietic stem cell transplantation, rapid and accurate microbiology diagnostics are essential to the practice of transplant clinicians, including infectious diseases specialists. In the last decade, diagnostic microbiology has seen a shift toward culture-independent techniques including single-target and multiplexed molecular testing, mass-spectrometry, and magnetic resonance-based methods which have together greatly expanded the array of pathogens identified, increased processing speed and throughput, allowed for detection of resistance determinants, and ultimately improved the outcomes of infected transplant recipients. More recently, a newer generation of diagnostics with immense potential has emerged, including multiplexed molecular panels directly applicable to blood and blood culture specimens, next-generation metagenomics, and gas chromatography mass spectrometry. Though these methods have some recognized drawbacks, many have already demonstrated improved sensitivity and a positive impact on clinical outcomes in transplant and immunocompromised patients.

Feasibility and Comparison Study of Fecal Sample Collection Methods in Healthy Volunteers and Solid Organ Transplant Recipients Using 16S rRNA and Metagenomics Approaches

The human microbiome encompasses a variety of microorganisms that change dynamically and are in close contact with the body. The microbiome influences health and homeostasis, as well as the immune system, and any significant change in this equilibrium (dysbiosis) triggers both acute and chronic health conditions. Microbiome research has surged, in part, due to advanced sequencing technologies enabling rapid, accurate, and cost-effective identification of the microbiome. A major prerequisite for stool sample collection to study the gut microbiome in longitudinal prospective studies requires standardized protocols that can be easily replicated. However, there are still significant bottlenecks to stool specimen collection that contribute to low patient retention rates in microbiome studies. These barriers are further exacerbated in solid organ transplant recipients where diarrhea is estimated to occur in up to half the patient population. We sought to test two relatively easy sample collection methods (fecal swab and wipes) and compare them to the more cumbersome "gold" standard collection method (scoop) using two different sequencing technologies (16S ribosomal RNA sequencing and shotgun metagenomics). Our comparison of the collection methods shows that both the swabs and the wipes are comparable to the scoop method in terms of bacterial abundance and diversity. The swabs, however, were closer in representation to the scoop and were easier to collect and process compared to the wipes. Potential contamination of the swab and the wipe samples by abundant skin commensals was low in our analysis. Comparison of the two sequencing technologies showed that they were complementary, and that 16S sequencing provided enough coverage to detect and differentiate between bacterial species identified in the collected samples. Our pilot study demonstrates that alternative collection methods for stool sampling are a viable option in clinical applications, such as organ transplant studies. The use of these methods may result in better patient retention recruitment rates in serial microbiome studies.

Newer approaches in diagnosis of diarrhea in immunocompromised patients

PURPOSE OF REVIEW

This review will focus on the epidemiology and cause of diarrheal illness in solid organ transplant and stem-cell transplant population recipients with a specific focus on the role of advanced multiplex technology in the diagnosis of diarrhea within this patient population.

RECENT FINDINGS

A wide range of infectious and noninfectious causes of diarrhea have been described in immunocompromised patients. The most common infections noted are Clostridioides difficile, norovirus, and cytomegalovirus, whereas immunosuppressive drugs and mucositis are the most common noninfectious causes of diarrhea. Historically, diagnostic evaluation has been limited to an array of single pathogen assays. Newer multiplex assays have become available that allow rapid, sensitive detection of a wide range of pathogens in a single assay. These assays have improved the number of patients with a diagnosed pathogen but may identify colonizing pathogens that are not pathogenic. Studies are needed to inform the discrimination and optimal use of these newer assays.

SUMMARY

Diarrhea is a common complication in immunocompromised patients and is associated with greater morbidity and rare mortality. New diagnostics facilitate detection of recognized pathogens and may allow for improved outcomes through the use of pathogen-targeted therapy.

Diarrhea in kidney transplant recipients: Etiology and outcome

BACKGROUND AND AIM

Diarrhea in kidney transplant recipients influences outcome of transplantation. Data from India in this regard are sparse and do not address the differential outcome of infective and non-infective diarrhea. We studied the demographic data, laboratory findings, treatment response, disease duration, and outcome of diarrhea in kidney transplant recipients, and the differential outcome between infective and non-infective diarrhea, if any.

METHODS

All kidney transplant recipients who were referred to the Division of Gastroenterology with diarrhea between June 2015 and February 2017 were prospectively included. Demographic, clinical and laboratory data, graft function, treatment administered, and outcome were noted, and the patients were followed up for 3 months.

RESULTS

Forty-seven patients (median age 45 years, range 16-78; 34 men) with 64 episodes of diarrhea were studied. Thirty-three (51.5%) episodes were attributed to infections. Eleven (17%) were immunosuppressant-induced (mycophenolate 8, tacrolimus 2, cyclosporine 1). Twenty (31%) were due to other causes (antibiotics 6, laxatives 3, irritable bowel syndrome 3, sepsis 8). Fifty-three episodes (82%) had graft dysfunction during the diarrheal episodes. Mean increase in serum creatinine was 45% in the infectious diarrhea group and 95% in the non-infectious diarrhea group (p < 0.05). Median time to resolution of diarrhea was 3 days. With improvement in diarrhea, return to pre-diarrhea creatinine levels occurred in 87% of episodes at 3 months.

CONCLUSION

One-half of episodes of diarrhea in kidney transplant recipients were non-infectious in origin. Seventeen percent were attributed to immunosuppressants, requiring dose modification. More than 80% were associated with worsening of graft function. Recovery of graft function to baseline was seen in a majority of cases with the resolution of diarrhea.

Efficacy and Safety of a Quadruple Regimen Compared with Triple Regimens in Patients with Mycophenolic Acid-Related Gastrointestinal Complications After Renal Transplantation: A Short-Term Single-Center Study

Background

At present, there is no ideal conventional triple regimen that can effectively treat gastrointestinal (GI) complications in patients after kidney transplantation. We aimed to investigate the efficacy and safety of a quadruple regimen including standard-dose tacrolimus, low-dose enteric-coated mycophenolate sodium (EC-MPS), low-dose mizoribine (MZR), and corticosteroids, compared with regimens containing standard-dose tacrolimus, corticosteroids, plus either low-dose EC-MPS or standard-dose MZR in patients with mycophenolic acid (MPA)-related GI complications after renal transplantation.

Material/Methods

Between August 2016 and October 2018 in Qilu Hospital of Shandong University, 115 living donor kidney transplant recipients with MPA-related GI complications were enlisted in a single-center, prospective, randomized, control study. Thirty-six recipients were assigned to the low-dose EC-MPS plus low-dose MZR group, 37 recipients were assigned to the low-dose EC-MPS group, and 39 recipients were assigned to the standard-dose MZR group. We analyzed the Gastrointestinal Symptom Rating Scale (GSRS), estimated glomerular filtration rate (eGFR), graft rejection, serum creatinine, human leukocyte antigen (HLA) antibody, and the occurrence of adverse events among the 3 groups.

Results

Compared with baseline, gastrointestinal symptoms improved significantly in all 3 groups. The reduction in mean subscale scores from baseline to month 3 was more significant in the standard-dose MZR group compared with the other 2 groups. The low-dose EC-MPS plus low-dose MZR group had better renal function. The incidence of graft rejection and cytomegalovirus (CMV) and polyomavirus BK (BKV) infection, as well as the incidence of hyperuricemia, in the low-dose EC-MPS plus low-dose MZR group were all significantly reduced.

Conclusions

This quadruple regimen may be equivalent to regimens containing standard-dose tacrolimus, corticosteroids plus either low-dose EC-MPS or standard-dose MZR in improving GI symptoms after kidney transplant, and is also advantageous for kidney function, graft rejection, and the rates of adverse events.

Altered Gut Microbial Fermentation and Colonization with Methanobrevibacter smithii in Renal Transplant Recipients

Renal transplant recipients (RTRs) often suffer from posttransplant diarrhea. The observed dysbiosis in RTR may influence the fermentation processes in the gut. In this study, we aimed to investigate whether fermentation differs between RTRs and healthy controls (HCs), by measuring breath H₂ and CH₄ concentrations. Additionally, we determined the fecal presence of the methanogen Methanobrevibacter smithii (M. smithii), which plays a main role in the process of methanogenesis. Data from the TransplantLines Biobank and Cohort Study (NCT03272841) was used. A total of 142 RTRs and 77 HCs were included. Breath H₂ concentrations in RTRs were not significantly different from HCs. Breath CH₄ concentrations in RTRs were significantly lower compared with HCs (median [interquartile range (IQR)] 7.5 [3.9–10.6] ppm vs. 16.0 [8.0–45.5] ppm, p < 0.001). M. smithii was less frequently present in the feces of RTRs compared to HCs (28.6% vs. 86.4% resp., p < 0.001). Our findings regarding the altered methanogenesis in the gut of RTRs show similarities with previous results in inflammatory bowel disease patients. These findings provide novel insight into the alterations of fermentation after renal transplantation, which may contribute to understanding the occurrence of posttransplant diarrhea.

Characteristics and Dysbiosis of the Gut Microbiome in Renal Transplant Recipients

Renal transplantation is life-changing in many aspects. This includes changes to the gut microbiome likely due to exposure to immunosuppressive drugs and antibiotics. As a consequence, renal transplant recipients (RTRs) might suffer from intestinal dysbiosis. We aimed to investigate the gut microbiome of RTRs and compare it with healthy controls and to identify determinants of the gut microbiome of RTRs. Therefore, RTRs and healthy controls participating in the TransplantLines Biobank and Cohort Study (NCT03272841) were included. We analyzed the gut microbiome using 16S rRNA sequencing and compared the composition of the gut microbiome of RTRs to healthy controls using multivariate association with linear models (MaAsLin). Fecal samples of 139 RTRs (50% male, mean age: 58.3 ± 12.8 years) and 105 healthy controls (57% male, mean age: 59.2 ± 10.6 years) were collected. Median time after transplantation of RTRs was 6.0 (1.5-12.5)years. The microbiome composition of RTRs was significantly different from that of healthy controls, and RTRs had a lower diversity of the gut microbiome (p < 0.01). Proton-pump inhibitors, mycophenolate mofetil, and estimated glomerular filtration rate (eGFR) are significant determinants of the gut microbiome of RTRs (p < 0.05). Use of mycophenolate mofetil correlated to a lower diversity (p < 0.01). Moreover, significant alterations were found in multiple bacterial taxa between RTRs and healthy controls. The gut microbiome of RTRs contained more Proteobacteria and less Actinobacteria, and there was a loss of butyrate-producing bacteria in the gut microbiome of RTRs. By comparing the gut microbiome of RTRs to healthy controls we have shown that RTRs suffer from dysbiosis, a disruption in the balance of the gut microbiome.

Adherence profiles in kidney transplant patients: Causes and consequences

OBJECTIVE

Adherence is a dynamic phenomenon and a critical determinant of transplant patients outcome. The objective of this longitudinal study was to explore adherence in kidney transplant patients followed-up for up to three years after transplantation.

METHODS

Adherence was repeatedly estimated using the Morisky-Green-Levine 4-Item Medication Adherence Scale, in two successive cohorts of 345 (EPIGREN) and 367 (EPHEGREN) kidney transplant recipients. Mixed effect modeling with latent processes and latent classes was used to describe adherence time-profiles.

RESULTS

Two latent classes were identified. The adherent class represented 85% of the patients. Patients of the poorer-adherence class displayed a lower adherence at one month (p<10^-3), which worsened over time. Good adherence was associated with age >50 years, fewer depression episodes (5% vs. 13%, p = 0.001) and a better mental health component of quality of life (MCS-SF36 47 ± 11 vs. 41 ± 13, p = 0.015). Survival without acute rejection episodes was longer in the adherent class (p = 0.004).

CONCLUSIONS

The risk of poor adherence in renal transplant patients can be detected as early as one month post-transplantation, using appropriate and easy tools adapted to routine monitoring.

PRACTICE IMPLICATIONS

An early focus on vulnerable patients should allow putting into place actions in order to reduce the risk of poor outcome related to poor adherence.