Diagnostic yields in solid organ transplant recipients admitted with diarrhea

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.

Clostridioides difficile Infection in Kidney Transplant Recipients

Clostridioides difficile (C. difficile) is a bacterial organism that typically infects the colon, which has had its homeostasis of healthy gut microbiota disrupted by antibiotics or other interventions. Patients with kidney transplantation are a group that are susceptible to C. difficile infection (CDI) and have poorer outcomes with CDI given that they conventionally require long-term immunosuppression to minimize their risk of graft rejection, weakening their responses to infection. Recognizing the risk factors and complex pathophysiological processes that exist between immunosuppression, dysbiosis, and CDI is important when making crucial clinical decisions surrounding the management of this vulnerable patient cohort. Despite the clinical importance of this topic, there are few studies that have evaluated CDI in the context of kidney transplant recipients and other solid organ transplant populations. The current recommendations on CDI management in kidney transplant and solid organ transplant recipients are mostly extrapolated from data relating to CDI management in the general population. We provide a narrative review that discusses the available evidence examining CDI in solid organ transplant recipients, with a particular focus on the kidney transplant recipient, from the epidemiology of CDI, clinical features and implications of CDI, potential risk factors of CDI, and, ultimately, prevention and management strategies for CDI, with the aim of providing areas for future research development in this topic area.

Assessing the Impact of 2-Step Clostridioides difficile Testing at the Healthcare Facility Level

BACKGROUND

Two-step testing for Clostridioides difficile infection (CDI) aims to improve diagnostic specificity but may also influence reported epidemiology and patterns of treatment. Some providers fear that 2-step testing may result in adverse outcomes if C. difficile is underdiagnosed.

METHODS

Our primary objective was to assess the impact of 2-step testing on reported incidence of hospital-onset CDI (HO-CDI). As secondary objectives, we assessed the impact of 2-step testing on C. difficile-specific antibiotic use and colectomy rates as proxies for harm from underdiagnosis or delayed treatment. This longitudinal cohort study included 2 657 324 patient-days across 8 regional hospitals from July 2017 through March 2022. Impact of 2-step testing was assessed by time series analysis with generalized estimating equation regression models.

RESULTS

Two-step testing was associated with a level decrease in HO-CDI incidence (incidence rate ratio, 0.53 [95% confidence interval {CI}, .48-.60]; P < .001), a similar level decrease in utilization rates for oral vancomycin and fidaxomicin (utilization rate ratio, 0.63 [95% CI, .58-.70]; P < .001), and no significant level (rate ratio, 1.16 [95% CI, .93-1.43]; P = .18) or trend (rate ratio, 0.85 [95% CI, .52-1.39]; P = .51) change in emergent colectomy rates.

CONCLUSIONS

Two-step testing is associated with decreased reported incidence of HO-CDI, likely by improving diagnostic specificity. The parallel decrease in C. difficile-specific antibiotic use offers indirect reassurance against underdiagnosis of C. difficile infections still requiring treatment by clinician assessment. Similarly, the absence of any significant change in colectomy rates offers indirect reassurance against any rise in fulminant C. difficile requiring surgical management.

PCR-based versus conventional stool tests in children with diarrhea who underwent solid organ transplantation or hematopoietic stem cell transplantation

Infectious diarrhea is a common problem among post-transplant recipients. Compared to conventional tests, polymerase chain reaction (PCR)-based stool tests have been shown to improve diagnostic yield but the aforementioned data in children remain limited. Our aims were to assess the detection rate of PCR-based tests in post-transplant children and compare with the conventional tests; and to investigate how these stool tests help in managing these children. We enrolled children aged 1 to 19 years who underwent solid organ transplantation or hematopoietic stem cell transplantation that remained on immunosuppressive agents and developed diarrhea ≥ 24 hours between January 2015 and February 2023. Besides stool tests, data on demographics, clinical characteristics and management were collected. We analyzed 68 patients and 92 episodes of diarrhea with PCR-based tests. PCR-based tests provided a detection rate of 41.8% versus 16.5% for the conventional tests. While conventional tests may detect a higher proportion of Clostridiodes difficile infection, PCR-based tests showed greater yields in detecting Salmonella spp. and viruses especially norovirus. PCR-based tests had an impact in management among 22/38 (58%) diarrheal episodes especially with Campylobacter jejuni and C difficile; and among 16 episodes that positive PCR-based tests had a minimal impact, the most common reason was due to the need for continuation of antimicrobial agents for concomitant site-specific infection (69%). Among transplanted children presenting with diarrhea, PCR-based tests provide a higher yield when compared with the conventional tests. The PCR-based stool tests may also further guide clinicians for providing proper antimicrobial agents.

Approach to patient reported outcome measures selection and implementation in a chronic norovirus clinical efficacy trial for patients after solid organ transplant

Norovirus is the second most common cause of diarrhea among solid organ transplant recipients. There are currently no approved therapies for Norovirus, which can substantially impact quality of life, particularly in an immunocompromised patient population. In order to establish clinical efficacy and support any medication claims related to a patient's symptoms or function, the Food and Drug Administration requires that a trial's primary endpoints be derived from patient reported outcome measures- an outcome that comes directly from the patient, without interpretation of the patient's response by a clinician or anyone else. In this paper, we describe our study team's approach to the definition, selection, measurement and evaluation of patient reported outcome measures as part of establishing clinical efficacy of Nitazoxanide for acute and chronic Norovirus in solid organ transplant recipients. We specifically describe our approach to measuring the primary efficacy endpoint- days to cessation of vomiting and diarrhea after randomization through 160 days, measured through daily symptom diaries as well as the impact of treatment on exploratory efficacy endpoints, particularly change in the impact of norovirus on psychological function and quality of life.

Successful management of life-threatening post-COVID-19 cryptosporidiosis in a renal transplant patient: a case report

Worldwide, Cryptosporidium spp. is a common parasite that affects domestic and wild animals, including humans, and causes diarrhea in both immunocompetent and immunocompromised hosts. The fecal-oral pathway accounts for the majority of its transfer. Although C. parvum and C. hominis are the most common zoonotic species in humans, other zoonotic species can also infect immunocompetent and immunocompromised people. Patients undergoing renal transplants are more likely to contract cryptosporidiosis, which can cause severe and potentially fatal diarrhea. A 41-year-old male patient who presented to the emergency department complained of a sudden onset, severe and continuous fatigue, and a feverish sensation of two-day duration. Two days prior to the current admission, the patient started to complain of weakness affecting his whole body, as well as a fever of 39°C and continuous yellowish diarrhea occurring 4-5 times daily without blood. Stool analysis revealed a cryptosporidium infection. The patient underwent surgery for kidney transplantation. The donated kidney was the left one from his brother and was attached to the patient´s right groin. As illustrated by our example, cryptosporidiosis should be considered a significant cause of acute, persistent, watery diarrhea in immunocompromised kidney transplant recipients. Patients undergoing renal transplants should be instructed to wash their hands frequently, stay away from young animals, sick people, and swimming pools in order to lower their risk of infection.

Infections after organ transplantation and immune response

Organ transplantation has provided another chance of survival for end-stage organ failure patients. Yet, transplant rejection is still a main challenging factor. Immunosuppressive drugs have been used to avoid rejection and suppress the immune response against allografts. Thus, immunosuppressants increase the risk of infection in immunocompromised organ transplant recipients. The infection risk reflects the relationship between the nature and severity of immunosuppression and infectious diseases. Furthermore, immunosuppressants show an immunological impact on the genetics of innate and adaptive immune responses. This effect usually reactivates the post-transplant infection in the donor and recipient tissues since T-cell activation has a substantial role in allograft rejection. Meanwhile, different infections have been found to activate the T-cells into CD₄⁺ helper T-cell subset and CD₈⁺ cytotoxic T-lymphocyte that affect the infection and the allograft. Therefore, the best management and preventive strategies of immunosuppression, antimicrobial prophylaxis, and intensive medical care are required for successful organ transplantation. This review addresses the activation of immune responses against different infections in immunocompromised individuals after organ transplantation.

An analysis of the outcomes of Clostridioides difficile occurring in intestinal transplant recipients requiring hospitalization

BACKGROUND

Organ transplantation is a known risk factor for Clostridioides difficile infection (CDI). There is limited published data on the impact of CDI in the intestinal transplant population.

METHODS

We utilized the National Readmission Database (2010-2017) to study the outcomes of CDI in patients having a history of intestinal transplantation. Association of CDI with readmission and hospital resource utilization was computed in multivariable models adjusted for demographics and comorbidities.

RESULTS

During 2010-2017, 8442 hospitalizations with the history of intestinal transplantation had indexed hospital admissions. Of these, 320 (3.8%) had CDI. CDI hospitalization in intestine transplant patients was associated with higher median cost $54 430 (IQR: 27 231, 109 980) as compared to patients who did not have CDI $48 888 (IQR: 22 578, 112 777), (β: 71 814 95% confidence intervals [CI]: 676-142 953, p = .048). The median length of stay was also longer for patients with CDI 7 (IQR: 4, 13) days as compared to 5 (IQR: 3, 11) days in non-CDI (β: 5.51 95% CI: 0.73-10.29, p = .02). The mortality rate, intestinal transplant complications, presence of malnutrition, acute kidney injury, ICU admissions, and sepsis were similar in both groups. CDI was the top cause of 30-day readmission in the intestinal transplant recipients with CDI during the index admission; the number of 30-day readmissions also increased from 2010 to 2017.

CONCLUSION

CDI hospitalization in post-intestine transplant patients occurs commonly and is associated with a longer length of stay and higher costs during hospitalization. The CDI was the most common cause of readmission after the index admission of CDI in these patients.

Infection prevention requirements for the medical care of immunosuppressed patients: recommendations of the Commission for Hospital Hygiene and Infection Prevention (KRINKO) at the Robert Koch Institute

In Germany, guidelines for hygiene in hospitals are given in form of recommendations by the Commission for Hospital Hygiene and Infection Prevention (Kommission für Krankenhaushygiene und Infektionsprävention, "KRINKO"). The KRINKO and its voluntary work are legitimized by the mandate according to § 23 of the Infection Protection Act (Infektionsschutzgesetz, "IfSG"). The original German version of this document was published in February 2021 and has now been made available to the international professional public in English. The guideline provides recommendations on infection prevention and control for immunocompromised individuals in health care facilities. This recommendation addresses not only measures related to direct medical care of immunocompromised patients, but also management aspects such as surveillance, screening, antibiotic stewardship, and technical/structural aspects such as patient rooms, air quality, and special measures during renovations.

Quantitative norovirus viral load is not affected by home storage of stool

In preparation of a clinical trial of norovirus treatment, there were concerns raised by FDA about risk of self‐storage of stool from patients infected with norovirus affecting quantitative assessments of norovirus RNA. Specifically, most home freezers are frost‐free and may expose the samples to multiple rounds of freeze‐thaw. Stool samples collected by the study team were stored at different lengths in a frost‐free freezer and at −80°C. Quantitative PCRs of norovirus were performed on all samples using the same assay. By all measures, there was no significant change in measured viral load with home storage.

Long-Term Infectious Complications of Kidney Transplantation

Infections remain a common complication of solid-organ transplantation. Most infections in the first month after transplant are typically health care-associated infections, whereas late infections, beyond 6-12 months, are community-acquired infections. Opportunistic infections most frequently present in the first 12 months post-transplant and can be modulated on prior exposures and use of prophylaxis. In this review, we summarize the current epidemiology of postkidney transplant infections with a focus on key viral (BK polyomavirus, cytomegalovirus, Epstein-Barr virus, and norovirus), bacterial (urinary tract infections and Clostridioides difficile colitis), and fungal infections. Current guidelines for safe living post-transplant are also summarized. Literature supporting prophylaxis and vaccination is also provided.

Viral infections in lung transplantation

Viral infections account for up to 30% of all infectious complications in lung transplant recipients, remaining a significant cause of morbidity and even mortality. Impact of viral infections is not only due to the direct effects of viral replication, but also to immunologically-mediated lung injury that may lead to acute rejection and chronic lung allograft dysfunction. This has particularly been seen in infections caused by herpesviruses and respiratory viruses. The implementation of universal preventive measures against cytomegalovirus (CMV) and influenza (by means of antiviral prophylaxis and vaccination, respectively) and administration of early antiviral treatment have reduced the burden of these diseases and potentially their role in affecting allograft outcomes. New antivirals against CMV for prophylaxis and for treatment of antiviral-resistant CMV infection are currently being evaluated in transplant recipients, and may continue to improve the management of CMV in lung transplant recipients. However, new therapeutic and preventive strategies are highly needed for other viruses such as respiratory syncytial virus (RSV) or parainfluenza virus (PIV), including new antivirals and vaccines. This is particularly important in the advent of the COVID-19 pandemic, for which several unanswered questions remain, in particular on the best antiviral and immunomodulatory regimen for decreasing mortality specifically in lung transplant recipients. In conclusion, the appropriate management of viral complications after transplantation remain an essential step to continue improving survival and quality of life of lung transplant recipients.

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.

Fatal Case of Perforated Cytomegalovirus Colitis: Case Report and Systematic Review

Objective: We describe a patient with history of heart transplant on maintenance immunosuppression who presented with sigmoid colon perforation from cytomegalovirus (CMV) colitis and performed a systematic review of outcomes after perforated CMV colitis. Background: Cytomegalovirus enterocolitis is uncommon among solid organ transplant patients and can result in small or large bowel perforation. Methods: We systematically reviewed articles describing patients with CMV enterocolitis with small or large bowel perforations from PubMed, Embase, and Web of Science from database inception to February 2021. Results: Seventy-seven articles were identified containing 84 patients with perforated CMV enterocolitis. The most prevalent comorbid diagnosis was human immunodeficiency virus (HIV; 27 patients, 32%), and 37 patients (44%) were taking corticosteroids at time of presentation. The ileum was the most common location for a perforation (26 patients, 31%). Odds of survival were lower for patients with small bowel perforation (odds ratio [OR], 0.38; 95% confidence interval [CI], 0.14-0.98) and HIV/acquired immunodeficiency syndrome (AIDS; OR, 0.32; 95% CI, 0.11-0.88). Odds of survival were higher for patients with large bowel perforation (OR, 2.64; 95% CI, 1.03-7.09), radiographically diagnosed perforation (OR, 3.45; 95% CI, 1.12-11.60) and those who received a CMV antiviral (OR, 9.19; 95% CI, 3.26-28.48). Conclusions: Perforated CMV enterocolitis is uncommon even in immunocompromised hosts. Clinicians should maintain a high level of suspicion for CMV-induced bowel perforation in this population because antiviral treatment is associated with increased odds of survival.

The outcomes of Clostridioides difficile infection in inpatient liver transplant population

BACKGROUND

Chronic immunosuppression is a known cause of Clostridioides difficile, which presents with colon infection. It is associated with increased mortality and morbidity. Our aim is to determine the inpatient outcomes of liver transplant patients with Clostridioides difficile infection (CDI) and trends in the last few years.

METHODS

We utilized the national re-admission data (2010-2017) to study the outcomes of CDI in liver transplant patients. Association of C. difficile with re-admission was computed in a multivariable model adjusted for age, sex, gastrointestinal bleeding, hypertension, diabetes, hyperlipidemia, congestive heart failure, cerebrovascular disease, obesity, cancer, insurance, chronic kidney disease, chronic obstructive pulmonary disease, dementia, peripheral vascular disease, smoking, hospital location, and teaching status.

RESULTS

During 2010-2017, there were 310 222 liver transplant patients hospitalized. Out of these, 9826 had CDI. CDI infection in liver transplant patients was associated with higher 30-day re-admission (14.3% vs. 11.21%, hazard ratio [HR]: 1.14, 95% confidence interval [CI]: 1.01-1.28, p = .02) and in-hospital mortality (odds ratio [OR]: 1.36, 95% CI: 1.14-1.61, p < .001). The most common causes of re-admission in the CDI group were recurrent CDI (41.1%), liver transplant complications (16.5%), and sepsis (11.6%). The median cost for liver transplant patients with C. difficile was significantly higher, $53 064 (IQR $24 970-$134 830) compared to patients that did not have C. difficile, $35 703 ($18 793-$73 871) (p < .001). The median length of stay was also longer for patients with CDI, 6 days (4-14) vs. 4 days (2-7) (p < .001).

CONCLUSION

CDI in post-liver transplant patients was associated with higher mortality, re-admission, health care cost, and longer length of stay. The most common cause of re-admission was recurrent CDI, which raises the question of the efficacy of standard first-line therapy.

Infectious Gastroenteritis in Transplant Patients

Infectious gastroenteritis is common after transplantation and can lead to increased morbidity and mortality. A wide range of organisms can lead to gastroenteritis in this patient population. Clostridioides difficile, cytomegalovirus, and norovirus are the most common pathogens. Newer diagnostic methods, especially multiplex polymerase chain reaction, have increased the diagnostic yield of infectious etiologies. In this review, we describe the epidemiology and risk factors for common infectious pathogens leading to gastroenteritis.

Viral Acute Gastroenteritis in Special Populations

Viral acute gastroenteritis (AGE) is common and afflicts people of all ages. Nonviral causes of AGE are less common. Norovirus is a leading cause of sporadic cases and outbreaks of AGE across all ages. Universal rotavirus vaccination of infants has reduced frequency and severity of rotavirus AGE cases in children and indirectly reduced cases in older adults. Severe illness is more likely in persons at age extremes or with immunocompromising conditions. Viral causes of AGE can lead to protracted diarrheal illness in immunocompromised persons. Nucleic acid amplification tests are changing diagnostic testing algorithms.

Healthcare associated diarrhea, not Clostridioides difficile

PURPOSE OF REVIEW

The aim of this article is to review the epidemiology, cause, diagnostic evaluation, and management of healthcare-associated diarrhea (HCAD) with particular attention to current epidemiology and recent developments in diagnostics.

RECENT FINDINGS

Multiplex polymerase chain reaction gastrointestinal panels allow rapid detection of a wide array of potential enteropathogens but the role, yield, and utility of these tests have not been systematically assessed in patients with HCAD. Recent epidemiologic studies reaffirm that HCAD is predominantly a noninfectious condition most often caused by medications or underlying medical conditions, sometimes Clostridioides difficile, and occasionally viruses. Other infections are rare.

SUMMARY

Clinical assessment remains fundamental to the evaluation of HCAD and targeted testing for C. difficile is sufficient in most patients. Multiplex gastrointestinal panels may have a role in immunocompromised patients but more study is needed. Medication-induced diarrhea is common and underappreciated and not limited to antibiotics, laxatives, and enemas.

Clinical characteristics, risk factors and outcome of severe Norovirus infection in kidney transplant patients: a case-control study

Background

Human Norovirus (HuNoV) has recently been identified as a major cause of diarrhea among kidney transplant recipients (KTR). Data regarding risk factors associated with the occurrence of HuNoV infection, and its long-term impact on kidney function are lacking.

Methods

We conducted a retrospective case-control study including all KTR with a diagnosis of HuNoV diarrhea. Each case was matched to a single control according to age and date of transplantation, randomly selected among our KTR cohort and who did not develop HuNoV infection. Risk factors associated with HuNoV infection were identified using conditional logistic regression, and survival was estimated using Kaplan-Meier estimator.

Results

From January 2012 to April 2018, 72 cases of NoV diarrhea were identified among 985 new KT, leading to a prevalence of HuNoV infection of 7.3%. Median time between kidney transplantation and diagnosis was 46.5 months (Inter Quartile Range [IQR]:17.8–81.5), and the median duration of symptoms 40 days (IQR: 15–66.2). Following diagnosis, 93% of the cases had a reduction of immunosuppression. During follow-up, de novo Donor Specific Antibody (DSA) were observed in 8 (9%) cases but none of the controls (p = 0.01). Acute rejection episodes were significantly more frequent among cases (13.8% versus 4.2% in controls; p = 0,03), but there was no difference in serum creatinine level at last follow-up between the two groups (p = 0.08). Pre-transplant diabetes and lymphopenia below 1000/mm³ were identified as risks factors for HuNoV infection in multivariate analysis.

Conclusion

HuNoV infection is a late-onset and prolonged infection among KTR. The current management, based on the reduction of immunosuppressive treatment, is responsible for the appearance of de novo DSA and an increase in acute rejection episodes.

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.

Etiological Spectrum of Infective Diarrhea in Renal Transplant Patient by Stool PCR: An Indian Perspective

Introduction:

Diarrhea is a common cause of morbidity and mortality among renal transplant patients. The etiological spectrum of pathogens varies with regional diversity, socioeconomic conditions, sanitation, and eating habits. We aimed to delineate the etiological profile of gastrointestinal pathogens in renal transplant patients using the stool Polymerase chain reaction.

Methods:

In this single-center, retrospective analysis of patients from January 2016 to January 2018, all renal transplant patients who were admitted with severe diarrhea and underwent the stool Polymerase chain reaction (PCR) were included. In the control group, we included patients from the general population who were admitted with similar complaints in the general medicine ward and underwent stool PCR over the same duration.

Results:

One hundred ten admissions occurred over 2 years in the transplant group. 86% of samples were positive for infection. More than one organism was seen in 68% of the patient. Norovirus was the most common organism isolated. Giardia lamblia with Norovirus was the most common coinfection among the transplant population. In the control group, 87% of samples tested positive, with 53% of patients having more than one organism. Enteroaggregative E. coli was the common organism, Enteroaggregative E. coli with Enteropathogenic E. coli and Enterotoxigenic E. coli were the most common organism in combination. Both the groups had similar incidence of infection with multiple organisms.

Conclusion:

The etiological profile of gastrointestinal pathogens differs significantly between the transplant and general population. Coinfections are common in both populations. Norovirus is the most common pathogen in the transplant population, presenting as isolated as well as in coinfections.

Clostridium difficile disease in solid organ transplant recipients: a recommended treatment paradigm

PURPOSE OF REVIEW

Organ transplant recipients have an increased incidence of Clostridium difficile disease and lower clinical response rates compared with the general population. Transplant specific treatment approaches are not defined. Therefore, a review of therapeutics in the transplant population is needed.

RECENT FINDINGS

A literature review on the current therapies for C. difficile was performed focusing on the evidence in transplant recipients and immunosuppressed populations.

SUMMARY

Transplant patients warrant an aggressive approach to treatment. The authors propose a suggested treatment paradigm for therapy.

Inflammatory bowel disease and solid organ transplantation

The population of patients with inflammatory bowel disease (IBD) and solid organ transplant (SOT) is increasing. Two clinical scenarios exist, recurrence of pre-existing IBD, which is more common, and de novo development of IBD, with a much higher incidence than in the general population. Their clinical course differs and may have a negative impact on the graft in both cases. The pathophysiological mechanisms remain unknown and no specific treatment recommendations are available. The combined effect of biologic therapy against IBD and immunosuppressive therapy against a potential rejection means that close monitoring is mandatory to identify infection, autoimmune events and malignancies. The colorectal cancer (CRC) rate is higher in this population. The group at greatest risk are patients with IBD undergoing liver transplantation (LT) for primary sclerosing cholangitis (PSC).

Multi-organism gastrointestinal polymerase chain reaction positivity among pediatric transplant vs non-transplant populations: A single-center experience

BACKGROUND

Diarrhea is a common problem in the pediatric post-solid organ transplant and post-hematopoietic stem cell transplant populations. Infectious etiology incidences are poorly defined, and the possibility of multi-organism positivity is often uninvestigated. The aim of this study is to utilize stool multiplex GIP assays to compare the PTP and NTP regarding the incidence and profiles of single-organism and multi-organism infectious diarrhea.

METHODS

A single-center retrospective review was conducted, investigating stool multiplex GIP panel results over a more than 3-year period, for pediatric patients. Assays test for 23 viral, bacterial, and protozoal organisms.

RESULTS

Positive assays in the PTP and NTP were 70/101 (69.3%) and 962/1716 (56.1%), respectively (P = .009). Thirty-two percent (32/101) of assays within the PTP were multi-organism positive, significantly more than 14.8% (254/1716) in the NTP (P < .00001). There was no significant difference in the incidence of single-organism positives, 37.6% (38/101) in PTP and 41.3% (708/1716) in the NTP. The PTP demonstrated a statistically significantly higher incidence of the following organisms within multi-agent positive GIPs (P < .05 for each): Clostridioides difficile, Cryptosporidium, EPEC, norovirus, and sapovirus.

CONCLUSIONS

The pediatric PTP demonstrates higher incidence of positive GIPs, higher rate of multi-organism positivity, and unique infectious organism incidence profiles. These data can provide a framework for understanding organism-specific pathogenicity factors, assessing the clinical impact of enteric co-infection, and understanding the utility of this testing modality in this unique population.

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.

Real-life food-safety behavior and incidence of foodborne infections in solid organ transplant recipients

Food-safety measures are recommended in solid organ transplant (SOT) recipients. However, the actual adherence of patients in a real-life setting and the impact on the incidence of foodborne infections remain largely unexplored. We performed a survey among SOT recipients followed at our institution, aiming to evaluate their food-safety behavior. We assessed the incidence of microbiologically proven foodborne infections by chart review. One hundred ninety-seven SOT recipients (kidney = 117, lung = 35, liver = 29, and heart = 16) participated in the survey. Overall, 17.7% of the participants observed all food-safety recommendations (22.0% avoided food at risk of contamination while 67.9% applied hygiene recommendations). Patients within the first year after transplantation (odds ratio [OR] 5.42; P = .001) and females (OR 4.67; P = .001) followed food-safety recommendations more closely. Although the majority of SOT recipients felt concerned and actively sought information on food safety (68%-70%), only 27% were able to recognize all risks of foodborne infection in hypothetical scenarios. Incidence of proven foodborne infections was 17.9% (95% confidence interval 9.9%-30.9%) 5 years after transplantation. Importantly, foodborne infections occurred exclusively among patients not following food-safety recommendations. In summary, most SOT recipients eat foods that make them at risk of foodborne infections. Our results indicate that there is room for improvement in patient education, particularly later after transplantation, and reinforce current food-safety recommendations.

Acute Kidney Injury in Hospitalized Kidney Transplant Recipients

BACKGROUND

Acute kidney injury (AKI) is a main cause of morbidity, hospitalization, and hospital readmission in kidney transplant recipients. We aimed to determine AKI incidence and risk factors following kidney transplant to assess outcomes such as renal function and graft loss after AKI.

METHODS

We conducted a retrospective cohort study with hospitalized kidney transplant recipients during 2016 to 2017. Clinical data of 179 patients were reviewed. The primary outcome was AKI incidence and risk factors. To determine AKI occurrence, we based it on creatinine criteria from Acute Kidney Injury Network classification.

RESULTS

We documented a total of 179 hospital admissions; AKI was diagnosed in 104 patients (58.1%). Recipients with higher baseline serum creatinine (odds ratio, 2.6; confidence interval [CI], 1.5-4.5; P < .001) and hospital admission because of infections (odds ratio, 2.4; CI, 1.1-5.2; P = .020) were more likely to experience AKI. A total of 19 recipients (10.6%) had graft loss with a significant AKI association (P = .003) at 12 months after admission. Intensive care unit length of stay (P = .63) and hospital stay (P = .55) were not different in patients with AKI compared with the control group.

CONCLUSIONS

As a main clinical finding, we concluded that infections and higher serum creatinine baseline level were associated with the development of AKI.

Molecular Diagnostic Advances in Transplant Infectious Diseases

PURPOSE OF REVIEW

The infectious complications of transplantation can have devastating consequences for patients. Early and accurate diagnosis is essential to good outcomes. This review describes recent advances in pathogen-directed diagnostic testing and discusses the role of new methods for transplant infectious diseases.

RECENT FINDINGS

Several molecular assays have been introduced into clinical practice in recent years. When the results of rapid testing are linked to patient-specific interventions, improved outcomes can be realized. Syndromic testing along with metagenomic next-generation sequencing (mNGS) represents novel approaches to infection diagnosis. However, the optimal use of these tests for transplant patients along with an overall assessment of cost-effectiveness demands further study. Molecular diagnostics are revolutionizing transplant care. Clinicians need to be aware of the current diagnostic landscape and have a working knowledge of the nuances related to test performance, result interpretation, and cost.

Gastrointestinal pathogen colonization and the microbiome in asymptomatic kidney transplant recipients

BACKGROUND

In kidney transplant recipients, gastrointestinal (GI) pathogens in feces are only evaluated during diarrheal episodes. Little is known about the prevalence of GI pathogens in asymptomatic individuals in this population.

METHODS

We recruited 142 kidney transplant recipients who provided a non-diarrheal fecal sample within the first 10 days after transplantation. The specimens were evaluated for GI pathogens using the BioFire^® FilmArray^® GI Panel (BioFire Diagnostics, LLC), which tests for 22 pathogens. The fecal microbiome was also characterized using 16S rRNA gene sequencing of the V4-V5 hypervariable region. We evaluated whether detection of Clostridioides difficile and other GI pathogens was associated with post-transplant diarrhea within the first 3 months after transplantation.

RESULTS

Among the 142 subjects, a potential pathogen was detected in 43 (30%) using the GI Panel. The most common organisms detected were C difficile (n = 24, 17%), enteropathogenic Escherichia coli (n = 8, 6%), and norovirus (n = 5, 4%). Detection of a pathogen on the GI panel or detection of C difficile alone was not associated with future post-transplant diarrhea (P > .05). The estimated number of gut bacterial species was significantly lower in subjects colonized with C difficile than those not colonized with a GI pathogen (P = .01).

CONCLUSION

Colonization with GI pathogens, particularly C difficile, is common at the time of kidney transplantation but does not predict subsequent diarrhea. Detection of C difficile carriage was associated with decreased microbial diversity and may be a biomarker of gut dysbiosis.

Intestinal parasites including Cryptosporidium, Cyclospora, Giardia, and Microsporidia, Entamoeba histolytica, Strongyloides, Schistosomiasis, and Echinococcus: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of intestinal parasites in the pre- and post-transplant period. Intestinal parasites are prevalent in the developing regions of the world. With increasing travel to and from endemic regions, changing immigration patterns, and the expansion of transplant medicine in developing countries, they are increasingly recognized as a source of morbidity and mortality in solid-organ transplant recipients. Parasitic infections may be acquired from the donor allograft, from reactivation, or from de novo acquisition post-transplantation. Gastrointestinal multiplex assays have been developed; some of the panels include testing for Cryptosporidium, Cyclospora, Entamoeba histolytica, and Giardia, and the performance is comparable to conventional methods. A polymerase chain reaction test, not yet widely available, has also been developed to detect Strongyloides in stool samples. New recommendations have been developed to minimize the risk of Strongyloides donor-derived events. Deceased donors with epidemiological risk factors should be screened for Strongyloides and recipients treated if positive as soon as the results are available. New therapeutic agents and studies addressing the optimal treatment regimen for solid-organ transplant recipients are unmet needs.

Diagnosis and management of diarrhea in solid-organ transplant recipients: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of diarrhea in the pre- and post-transplant period. Diarrhea in an organ transplant recipient may result in significant morbidity including dehydration, increased toxicity of medications, and rejection. Transplant recipients are affected by a wide range of etiologies of diarrhea with the most common causes being Clostridioides (formerly Clostridium) difficile infection, cytomegalovirus, and norovirus. Other bacterial, viral, and parasitic causes can result in diarrhea but are far less common. Further, noninfectious causes including medication toxicity, inflammatory bowel disease, post-transplant lymphoproliferative disease, and malignancy can also result in diarrhea in the transplant population. Management of diarrhea in this population is directed at the cause of the diarrhea, instituting therapy where appropriate and maintaining proper hydration. Identification of the cause to the diarrhea needs to be timely and focused.

Cryptosporidiosis and microsporidiosis as causes of diarrhea in kidney and/or pancreas transplant recipients

INTRODUCTION

Gastrointestinal disorders in solid organ recipients may have various origins including cryptosporidiosis and microsporidiosis. The prevalence of these infections is poorly known in solid organ transplant (SOT) patients in industrialized countries.

METHODS

We prospectively assessed the infectious causes of diarrhea in SOT patients. Secondary objectives were to gain further insight into the main characteristics of cryptosporidiosis, and to assess risk factors for this infection. All adult kidney and/or pancreas recipients presenting with diarrhea and admitted to our facility between May 1, 2014 and June 30, 2015 were enrolled. A stool sample was analyzed using a standardized protocol including bacteriological, virological, and parasitological investigations. Data related to clinical symptoms, immunosuppression, and environmental potential risk factors were collected through a self-administered questionnaire and computerized medical records.

RESULTS

Out of 73 enrolled patients, 36 had infectious diarrhea (49.3%). Viruses ranked first (17/36), followed by parasites and fungi (11/17). Cryptosporidiosis was the most common parasitic disease (n=6 patients). We observed four microsporidiosis cases. The estimated prevalence of cryptosporidiosis and microsporidiosis in this cohort was 3.7 and 2.4⁰/₀₀, respectively_. No significant risk factor for cryptosporidiosis or microsporidiosis, neither environmental nor immunological, could be evidenced.

CONCLUSION

Both cryptosporidiosis and microsporidiosis represent a significant cause of diarrhea in kidney transplant recipients.

A Case of Intestinal Microsporidiosis in a Renal Transplant Recipient

Post-renal transplant diarrhea is a common clinical presentation. An extensive list of potential etiology adds to the diagnostic dilemma. In cases of prolonged or intractable diarrhea, invasive tests are often performed. Intestinal microsporidia can be diagnosed with simple non-invasive stool polymerase chain reaction (PCR). Based on this case, we propose an easy to follow flow chart and present a literature review on post-renal transplant diarrhea. Further multicenter validation testing is required for the proposed flow chart.

Reduced Clostridioides difficile Tests Among Solid Organ Transplant Recipients Through a Diagnostic Stewardship Bundled Intervention

BACKGROUND Clostridioides difficile infection (CDI) is a frequent complication of solid organ transplantation, especially in the early post-transplantation period. Overdiagnosis of CDI is likely common in hospitals using nucleic acid amplification testing (NAAT), potentially leading to unnecessary iatrogenesis and cost. Recently, multiple studies have shown that computerized clinical decision support (CCDS)-based interventions can significantly reduce inappropriate C. difficile testing and healthcare facility-onset CDI events across hospitals and health systems. We aimed to determine if a CCDS-based intervention could reduce C. difficile testing and surveillance infection events among recent solid organ transplant recipients, a population at high risk for CDI. We also sought to determine the safety of the CCDS intervention. MATERIAL AND METHODS Quasi-experimental census-adjusted interrupted time-series analyses were performed retrospectively to examine testing and CDI events pre- and post-intervention. Mortality and readmissions rates were also examined. RESULTS A significant 33% relative reduction in tests and a nonsignificant trend towards fewer CDI events were observed following the intervention, without significant differences in mortality or 30-day readmission. A review of patients with positive C. difficile NAATs after prevented tests revealed no specific adverse events attributable to a possible delay in CDI diagnosis. CONCLUSIONS CCDS may be a helpful and safe adjunctive strategy to reduce unnecessary testing in accordance with guideline recommendations among solid organ transplant recipients.

Fecal microbiota transplantation for the treatment of recurrent and severe Clostridium difficile infection in solid organ transplant recipients: A multicenter experience

Fecal microbiota transplant (FMT) is recommended for Clostridium difficile infection (CDI) treatment; however, use in solid organ transplantation (SOT) patients has theoretical safety concerns. This multicenter, retrospective study evaluated FMT safety, effectiveness, and risk factors for failure in SOT patients. Primary cure and overall cure were defined as resolution of diarrhea or negative C difficile stool test after a single FMT or after subsequent FMT(s) ± anti-CDI antibiotics, respectively. Ninety-four SOT patients underwent FMT, 78% for recurrent CDI and 22% for severe or fulminant CDI. FMT-related adverse events (AE) occurred in 22.3% of cases, mainly comprising self-limiting conditions including nausea, abdominal pain, and FMT-related diarrhea. Severe AEs occurred in 3.2% of cases, with no FMT-related bacteremia. After FMT, 25% of patients with underlying inflammatory bowel disease had worsening disease activity, while 14% of cytomegalovirus-seropositive patients had reactivation. At 3 months, primary cure was 58.7%, while overall cure was 91.3%. Predictors of failing a single FMT included inpatient status, severe and fulminant CDI, presence of pseudomembranous colitis, and use of non-CDI antibiotics at the time of FMT. These data suggest FMT is safe in SOT patients. However, repeated FMT(s) or additional antibiotics may be needed to optimize rates of cure with FMT.

Baseline graft status is a critical predictor of kidney graft failure after diarrhoea

Background

Diarrhoea is one of the most frequent complications after kidney transplantation (KT). Non-infectious diarrhoea has been associated with reduced graft survival in kidney transplant recipients. However, the risk factors for renal allograft loss following diarrhoea remain largely unknown.

Methods

Between January 2010 and August 2011, 195 consecutive KT recipients who underwent standardized microbiological workups for diarrhoea at a single centre were enrolled in this retrospective study.

Results

An enteric pathogen was readily identified in 91 patients (47%), while extensive microbiological investigations failed to find any pathogen in the other 104. Norovirus was the leading cause of diarrhoea in these patients, accounting for 30% of the total diarrhoea episodes. The baseline characteristics were remarkably similar between non-infectious and infectious diarrhoea patients, with the exception that the non-infectious group had significantly lower graft function before diarrhoea (P = 0.039). Infectious diarrhoea was associated with a longer duration of symptoms (P = 0.001) and higher rates of acute kidney injury (P = 0.029) and hospitalization (P &lt; 0.001) than non-infectious diarrhoea. However, the non-infectious group had lower death-censored graft survival than the infectious group (Gehan–Wilcoxon test, P = 0.038). Multivariate analysis retained three independent predictors of graft failure after diarrhoea: diarrhoea occurring ≥5 years after KT [hazard ratio (HR) 4.82; P &lt; 0.001], re-transplantation (HR 2.38; P = 0.001) and baseline estimated glomerular filtration rate &lt;30 mL/min/1.73 m2 (HR 11.02; P &lt; 0.001).

Conclusion

Our study shows that pre-existing conditions (re-transplantation, chronic graft dysfunction and late occurrence) determine the primary functional long-term consequences of post-transplant diarrhoea.

The evaluation of critically ill transplant patients with infectious diarrhea

PURPOSE OF REVIEW

The review summarizes the epidemiology, risk factors, clinical presentation, diagnosis and management of the most important etiologic agents of infectious diarrhea in critically ill transplant recipients.

RECENT FINDINGS

Diarrhea, frequently caused by infectious pathogens, can cause significant morbidity and mortality in transplant recipients. Diarrhea can lead to severe dehydration, acute renal failure, medication toxicity, rejection, graft-versus-host disease and impairs patients' quality of life. Opportunistic infectious pathogens can pose significant diagnostic and therapeutic challenges in immunocompromised hosts.

SUMMARY

In transplant recipients, it is vital to differentiate infectious from noninfectious diarrhea to adequately manage their therapeutic approach. Supportive measures and reduction in immunosuppression are essential for the treatment management.

Rapid diagnosis of parasitic diseases: current scenario and future needs

BACKGROUND

Parasitic diseases are one of the world's most devastating and prevalent infections, causing millions of morbidities and mortalities annually. In the past, many of these infections have been linked predominantly to tropical or subtropical areas. Nowadays, however, climatic and vector ecology changes, a significant increase in international travel, armed conflicts, and migration of humans and animals have influenced the transmission of some parasitic diseases from 'book pages' to reality in developed countries. It has also been noted that many patients who have never travelled to endemic areas suffer from blood-borne infections caused by protozoa. In the light of existing knowledge, this new trend can be explained by the fact that in the process of migration a large number of asymptomatic carriers become a part of the blood bank donor and transplant donor populations. Accurate and rapid diagnosis represents the crucial weapon in the fight against parasitic infections.

AIMS

To review old and new approaches for rapid diagnosis of parasitic infections.

SOURCES

Data for this review were obtained through searches of PubMed using combinations of the following terms: parasitological diagnostics, microscopy, lateral flow assays, immunochromatographic assays, multiplex-PCR, and transplantation.

CONTENT

In this review, we provide a brief account of the advantages and limitations of rapid methods for diagnosis of parasitic diseases and focus our attention on current and future research in this area. The approximate costs associated with the use of different techniques and their applicability in endemic and non-endemic areas are also discussed.

IMPLICATIONS

Microscopy remains the cornerstone of parasitological diagnostics, especially in the field and low-resource settings, and provides epidemiological assessment of parasite burden. However, increased use and availability of point-of-care tests and molecular assays in modern era allow more rapid and accurate diagnoses and increased sensitivity in the identification of parasitic infections.

The role of multiplex molecular panels for the diagnosis of gastrointestinal infections in immunocompromised patients

PURPOSE OF REVIEW

An increasing number of laboratories have implemented multiplex molecular panels for the diagnosis of gastrointestinal infections. This review focuses on recent data addressing the performance of US Food and Drug Administration-cleared multiplex gastrointestinal panels and discusses the advantages and limitations of these tests in the immunocompromised population.

RECENT FINDINGS

Testing for gastrointestinal pathogens using multiplex molecular panels increases sensitivity and detection of coinfections compared with routine testing methods. Furthermore, multiplex panels reduce turnaround time and may allow for more informed decisions regarding treatment and infection control measures. However, the routine use of multiplex gastrointestinal panels has led to an increase in the detection of certain organisms, such as enteroaggregative Escherichia coli and sapovirus, which many clinical laboratories did not specifically test for in the past. This has created a degree of confusion on how to best interpret the results of multiplex panels, especially in the immunocompromised host.

SUMMARY

Multiplex molecular panels provide a rapid and sensitive tool for the diagnosis of infectious diarrhea, and may allow for more timely decisions regarding the management of immunosuppressed patients. However, there are limitations associated with multiplex panels, including the interpretation of results and the cost associated with testing. Clinical microbiologists should work closely with clinicians to develop evidence-based algorithms to guide test utilization in this area.

Underutilization of norovirus testing in hematopoietic cell transplant recipients at a large cancer center

The development of a new laboratory-developed norovirus assay provided an opportunity to assess testing patterns, incidence, and outcomes of norovirus among hematopoietic cell transplant (HCT) recipients. Clostridium difficile and norovirus tests from 1,393 HCT recipients were compared in these analyses. In this population of high-risk patients, norovirus appeared to occur seasonally, but testing was infrequent despite a correlation with more severe disease when compared with patients with C difficile infection.

The clinical features and infectious etiologies of acute diarrhea in immunocompromised hosts

Objectives The acute diarrhea is a common complaint among immunocompromised hosts, and may cause life threatening event. The infectious etiologies vary depending on virus, bacteria, and parasites. The most common etiology of acute gastroenteritis is known as enteric virus in Korea. But there are few studies about the infectious etiology of acute gastroenteritis in immunocompromised hosts. The aim of this study was to investigate the infectious etiologies of acute diarrhea in immunocompromised hosts. Methods Seventy three patients were enrolled prospectively in a university hospital from January 2013 to July 2014. Immunocompromised hosts included above 65-year-old people, patients with chronic diseases, solid organ or stem cell transplants, solid organ malignancies, hematologic malignancies, immunosuppressive or steroid taking patients. The clinical data were collected and stool samples collected during diarrhea were undergone laboratory analysis for enteric viruses and bacterial enteropathogens including Salmonella spp., Shigella spp., and Clostridium difficile. Results Fifty five patients were analyzed as follows : above 65 year-old people were 36 cases (66%), previous antibiotic usage was 22 cases (41.5%). 44 cases (81.1%) were admitted to general ward whereas 9 cases to ICU (17%). 41 cases (73.6%) were treated with antibiotics. Positive C. difficile toxin assays were 6 cases (11.9%). Other infectious etiologies were not found. Conclusions C. difficile infection was more common infectious etiology while enteric viruses and other bacteria are not associated with acute diarrhea among immunocompromised hosts in this study. So C. difficile infection must be considered preferentially in immunocompromised hosts with acute diarrhea.

Differentiating Posttransplant Inflammatory Bowel Disease and Other Colitides in Renal Transplant Patients

Renal transplant recipients who present with gastrointestinal complaints may have symptoms related to their underlying renal disease or secondary to their immunosuppressive regimen. Immunosuppression increases patients' risk for infection and medication-induced injury, and a subset of transplant patients develop a form of inflammatory bowel disease (IBD) despite being immunosuppressed. In this study, we present the spectrum of changes in colonic biopsy histology that occur in the postrenal transplant population, with emphasis on the clinical and histologic features that may allow distinction between several common disorders. Over a 15-year period, 51 postrenal transplant patients underwent colonoscopy with biopsy. Eleven (22%) patients had infectious colitis, and 10 of these had biopsy proven acute colitis. Another 17 (33%) patients were determined to have a medication-related injury based on resolution of symptoms following drug cessation. The majority (53%) of these colonic biopsies demonstrated crypt epithelial cell apoptosis and/or architectural distortion, although 41% were histologically normal. Four (8%) patients were ultimately diagnosed with a form of IBD after exclusion of other etiologies; biopsies from these patients demonstrated chronic active colitis or enteritis with plasma cell-rich expansion of the lamina propria and basal lymphoplasmacytosis. The increased prevalence of IBD in this patient cohort (4/700) compared with that reported in the overall North American population (1 to 2/700) is in line with prior studies and is likely related to the therapeutic regimen and associated immune dysregulation that occurs in solid-organ transplant recipients. We demonstrate that a combination of clinical, endoscopic, and histologic features are useful to distinguish among causes of gastrointestinal symptoms in this high risk population.