Donor derived Mycobacterium tuberculosis infection after solid-organ transplantation: A comprehensive review

Miliary Tuberculosis as Postmortem Diagnosis in Solid Organ Transplant Recipient: Case Report and Review of the Literature

BACKGROUND

The diagnosis of tuberculosis (TB) in solid organ transplant (SOT) recipients presents challenges that may lead to treatment delay. These include atypical clinical presentations, increased likelihood of negative tuberculin skin test or/and interferon-gamma release assays, and negative sputum smear results despite active disease. The treatment poses challenges due to pharmacokinetic interactions, allograft-related toxicity, and inadequate immune response.

CASE REPORT

We report the case of a 70-year-old man after kidney transplantation in 2012. The patient was transferred from the urology unit with deteriorating renal function and presumed urosepsis. His pulmonary chest X-ray showed hilar pulmonary infiltrates. Computed tomography of the chest/abdomen/pelvis revealed mediastinal lymphadenopathy, pulmonary infiltrates, pulmonary effusion, and splenomegaly. His blood results showed pancytopenia and high inflammatory and renal markers. He was treated with broad-spectrum antibiotics covering bacterial, fungal, and viral infections. Despite initial clinical improvement, his kidney function deteriorated, and he required hemodialysis. His temperature continued to spike. On physical examination, he was confused and lethargic. He was scheduled to have a mediastinoscopy with lymph node biopsy, but he died the day before. The postmortem examination revealed miliary tuberculosis with tuberculosis of many organs: kidney transplant, native kidney, bone marrow, mediastinal lymph nodes, lungs, and spleen.

CONCLUSIONS

The diagnosis of active TB in transplant recipients requires a high index of suspicion and invasive procedures. The majority of all cases of active TB after SOT are disseminated or occur at extrapulmonary sites. Only a small minority of patients have classic cavitary changes on pulmonary imaging.

Opportunistic Infections Post-Lung Transplantation: Viral, Fungal, and Mycobacterial

Opportunistic infections are a leading cause of lung transplant recipient morbidity and mortality. Risk factors for infection include continuous exposure of the lung allograft to the external environment, high levels of immunosuppression, impaired mucociliary clearance and decreased cough reflex, and impact of the native lung microbiome in single lung transplant recipients. Infection risk is mitigated through careful pretransplant screening of recipients and donors, implementation of antimicrobial prophylaxis strategies, and routine surveillance posttransplant. This review describes common viral, fungal, and mycobacterial infectious after lung transplant and provides recommendations on prevention and treatment.

Prevention and management of tuberculosis in solid organ transplantation: A consensus statement of the transplantation society of Taiwan

Solid organ transplant recipients have an increased risk of tuberculosis (TB). Due to the use of immunosuppressants, the incidence of TB among solid organ transplant recipients has been consistently reported to be higher than that among the general population. TB frequently develops within the first year after transplantation when a high level of immunosuppression is maintained. Extrapulmonary TB and disseminated TB account for a substantial proportion of TB among solid organ transplant recipients. Treatment of TB among recipients is complicated by the drug-drug interactions between anti-TB drugs and immunosuppressants. TB is associated with an increased risk of graft rejection, graft failure and mortality. Detection and management of latent TB infection among solid organ transplant candidates and recipients have been recommended. However, strategy to mitigate the risk of TB among solid organ transplant recipients has not yet been established in Taiwan. To address the challenges of TB among solid organ transplant recipients, a working group of the Transplantation Society of Taiwan was established. The working group searched literatures on TB among solid organ transplant recipients as well as guidelines and recommendations, and proposed interventions to strengthen TB prevention and care among solid organ transplant recipients.

Solid organ transplant recipients with tuberculosis disease in California, 2010 to 2020

Using California Tuberculosis (TB) Registry data from 2010-2020, we compared the presentation and outcomes of patients with TB aged >15 years with and without solid organ transplantation (SOT). We matched to the United Network for Organ Sharing registry for 1987-2020 and the estimated time from transplantation to the diagnosis of TB, the incidence of posttransplant TB, and the probability of death and graft failure in SOT recipients with TB, compared to those without TB. From 2010-2020, there were 148 posttransplant TB cases. Patients with posttransplant TB were more likely to have extrapulmonary disease and more than twice as likely to die as TB patients without SOT (relative risk [RR], 2.2; 95% confidence interval [CI], 1.6-2.9). The median time from transplantation to TB diagnosis was 1.2 years, with the shortest time among lung transplant recipients. The incidence of TB disease among Californians with SOT was 56.0 per 100 000 person-years. The risk of death was higher among SOT recipients with posttransplant TB than those without (adjusted hazard ratio, 2.8; 95% CI, 2.0-4.1); the risk of graft failure was higher among kidney transplant recipients with posttransplant TB than those without (adjusted hazard ratio, 3.4; 95% CI, 1.7-6.9). An increased risk of death and graft failure in SOT recipients with posttransplant TB highlights the need for enhanced pretransplant TB prevention.

Opportunistic Infections Post-Lung Transplantation: Viral, Fungal, and Mycobacterial

Opportunistic infections are a leading cause of lung transplant recipient morbidity and mortality. Risk factors for infection include continuous exposure of the lung allograft to the external environment, high levels of immunosuppression, impaired mucociliary clearance and decreased cough reflex, and impact of the native lung microbiome in single lung transplant recipients. Infection risk is mitigated through careful pretransplant screening of recipients and donors, implementation of antimicrobial prophylaxis strategies, and routine surveillance posttransplant. This review describes common viral, fungal, and mycobacterial infectious after lung transplant and provides recommendations on prevention and treatment.

Prevention, diagnosis, and management of donor derived infections in pediatric kidney transplant recipients

Donor derived infections (DDIs) in pediatric kidney transplant recipients remain challenging to diagnose and can result in serious morbidity and mortality. This review summarizes the current guidelines and recommendations for prevention, diagnosis, and treatment of unexpected DDIs in pediatric kidney transplant recipients. We provide a contemporary overview of DDI terminology, surveillance, epidemiology, and recommended approaches for assessing these rare events with an emphasis on the pediatric recipient. To address prevention and risk mitigation, important aspects of donor and pediatric candidate evaluations are reviewed, including current Organ Procurement and Transplantation Network (OPTN) and American Society of Transplantation (AST) recommendations. Common unexpected DDI encountered by pediatric transplant teams including multi-drug resistant organisms, tuberculosis, syphilis, West Nile Virus, toxoplasmosis, Chagas disease, strongyloidiasis, candidiasis, histoplasmosis, coccidioidomycosis, and emerging infections such as COVID-19 are discussed in detail. Finally, we consider the general challenges with management of DDIs and share our experience with a novel application of next generation sequencing (NGS) of microbial cell-free DNA that will likely define a future direction in this field.

Nationwide tuberculosis outbreak in the USA linked to a bone graft product: an outbreak report

BACKGROUND

Mycobacterium tuberculosis transmission through solid organ transplantation has been well described, but transmission through transplanted tissues is rare. We investigated a tuberculosis outbreak in the USA linked to a bone graft product containing live cells derived from a single deceased donor.

METHODS

In this outbreak report, we describe the management and severity of the outbreak and identify opportunities to improve tissue transplant safety in the USA. During early June, 2021, the US Centers for Disease Control and Prevention (CDC) worked with state and local health departments and health-care facilities to locate and sequester unused units from the recalled lot and notify, evaluate, and treat all identified product recipients. Investigators from CDC and the US Food and Drug Administration (FDA) reviewed donor screening and tissue processing. Unused product units from the recalled and other donor lots were tested for the presence of M tuberculosis using real-time PCR (rt PCR) assays and culture. M tuberculosis isolates from unused product and recipients were compared using phylogenetic analysis.

FINDINGS

The tissue donor (a man aged 80 years) had unrecognised risk factors, symptoms, and signs consistent with tuberculosis. Bone was procured from the deceased donor and processed into 154 units of bone allograft product containing live cells, which were distributed to 37 hospitals and ambulatory surgical centres in 20 US states between March 1 and April 2, 2021. From March 3 to June 1, 2021, 136 (88%) units were implanted into 113 recipients aged 24-87 years in 18 states (some individuals received multiple units). The remaining 18 units (12%) were located and sequestered. 87 (77%) of 113 identified product recipients had microbiological or imaging evidence of tuberculosis disease. Eight product recipients died 8-99 days after product implantation (three deaths were attributed to tuberculosis after recognition of the outbreak). All 105 living recipients started treatment for tuberculosis disease at a median of 69 days (IQR 56-81) after product implantation. M tuberculosis was detected in all eight sequestered unused units tested from the recalled donor lot, but not in lots from other donors. M tuberculosis isolates from unused product and recipients were more than 99·99% genetically identical.

INTERPRETATION

Donor-derived transmission of M tuberculosis via bone allograft resulted in substantial morbidity and mortality. All prospective tissue and organ donors should be routinely assessed for tuberculosis risk factors and clinical findings. When these are present, laboratory testing for M tuberculosis should be strongly considered.

FUNDING

None.

Disseminated tuberculosis in a lung transplant recipient presenting as tenosynovitis, subcutaneous nodules, and liver abscesses

Tuberculosis is of particular concern in lung transplant recipients. We present the case of a patient who received a double lung transplant from a deceased donor from Mexico and developed disseminated tuberculosis 60 days post-transplant manifested as tenosynovitis, liver abscesses, and subcutaneous nodules with no definitive lung allograft involvement. The recipient did not have evidence of tuberculosis on explanted lungs, had a negative interferon gamma release assay pre-transplant, and did not have risk factors for this infection. Mycobacterium tuberculosis should remain in the differential diagnosis of early post-transplant infections with atypical presentations, evidence of dissemination, or lack of improvement with appropriate antimicrobial coverage, even in the absence of typical lung findings.

Mycobacterium Tuberculosis Infection after Kidney Transplantation: A Comprehensive Review

Tuberculosis (TB) in kidney transplant (KT) recipients is an important opportunistic infection with higher incidence and prevalence than in the general population and is associated with important morbidity and mortality. We performed an extensive literature review of articles published between 1 January 2000 and 15 June 2022 to provide an evidence-based review of epidemiology, pathogenesis, diagnosis, treatment and outcomes of TB in KT recipients. We included all studies which reported epidemiological and/or outcome data regarding active TB in KT, and we approached the diagnostic and treatment challenges according to the current guidelines. Prevalence of active TB in KT recipients ranges between 0.3–15.2%. KT recipients with active TB could have a rejection rate up to 55.6%, a rate of graft loss that varies from 2.2% to 66.6% and a mortality rate up to 60%. Understanding the epidemiological risk, risk factors, transmission modalities, diagnosis and treatment challenges is critical for clinicians in providing an appropriate management for KT with TB. Among diagnostic challenges, which are at the same time associated with delay in management, the following should be considered: atypical clinical presentation, association with co-infections, decreased predictive values of screening tests, diverse radiological aspects and particular diagnostic methods. Regarding treatment challenges in KT recipients with TB, drug interactions, drug toxicities and therapeutical adherence must be considered.

Bacterial and Viral Infection and Sepsis in Kidney Transplanted Patients

Kidney transplanted patients are a unique population with intrinsic susceptibility to viral and bacterial infections, mainly (but not exclusively) due to continuous immunosuppression. In this setting, infectious episodes remain among the most important causes of death, with different risks according to the degree of immunosuppression, time after transplantation, type of infection, and patient conditions. Prevention, early diagnosis, and appropriate therapy are the goals of infective management, taking into account that some specific characteristics of transplanted patients may cause a delay (the absence of fever or inflammatory symptoms, the negativity of serological tests commonly adopted for the general population, or the atypical anatomical presentation depending on the surgical site and graft implantation). This review considers the recent available findings of the most common viral and bacterial infection in kidney transplanted patients and explores risk factors and outcomes in septic evolution.

Donor-derived tuberculosis among solid organ transplant recipients in the United States - 2008-2018

Mycobacterium tuberculosis can be transmitted via organ donation and result in severe outcomes. To better understand donor-derived tuberculosis (DDTB), all potential transmissions reported to the Organ Procurement and Transplantation Network (OPTN) Ad Hoc Disease Transmission Advisory Committee between 2008-2018 were analyzed. Among 51 total reports, nine (17%) (9 donors/35 recipients) had ≥1 recipient with proven/probable disease transmission. Of these, eight were reported due to recipient disease, and one was reported due to a positive donor result. Proven/probable DDTB transmissions were reported in six lung and five non-lung recipients. The median time to diagnosis was 104 days post-transplant (range 0-165 days). Pulmonary TB, extrapulmonary TB, pulmonary plus extrapulmonary TB, and asymptomatic TB infection with positive interferon-gamma release assay were present in five, three, one, and two recipients, respectively. All recipients received treatment and survived except for one whose death was not attributed to TB. All donors associated with proven/probable DDTB had ≥1 TB risk factor. Six were born in a TB-endemic country, five had traveled to a TB-endemic country, 3 had been incarcerated, and 3 had latent TB infection. These cases highlight the importance of evaluating donors for TB based on risk factors. Early post-transplant TB in organ recipients of donors with TB risk factors requires prompt reporting to OPTN to identify other potential affected recipients and implement timely treatment interventions. This article is protected by copyright. All rights reserved.

Clinical characteristics of tuberculous infection following renal transplantation

OBJECTIVE

This study investigated the clinical characteristics of patients with tuberculosis (TB) following renal transplantation (RT) in order to identify markers or signs that can facilitate early diagnosis.

METHODS

A retrospective analysis was performed on 12 cases of Mycobacterium tuberculosis infection treated at our hospital between 2005 and 2020.

RESULTS

The incidence of TB after RT at our hospital was 0.9%, and the median postoperative onset time was 22 months. The average age of patients included in our analysis was 44.2 ± 9.4 years; 11 of the 12 patients were male, and most patients had (low) fever as the first or only manifestation. Five patients had respiratory symptoms; 5 had typical computed tomography (CT) presentation; and 2 had a confirmed history of TB. Two sputum smears from 12 patients were positive by acid fast staining, and M. tuberculosis was detected in peripheral blood samples by metagenomic next-generation sequencing (NGS). One patient had a positive result in the purified protein derivative (PPD) test, 7 were positive with the interferon gamma release assay (IGRA), 8/12 patients were confirmed to have TB infection by NGS and 1 was confirmed positive by lung biopsy.

CONCLUSION

Because of the use of immunosuppressive agents, most patients with TB following RT have atypical clinical symptoms and CT findings, and may have a high probability of a false negative result with the traditional PPD test and a low probability of M. tuberculosis detection, making early diagnosis difficult. Therefore, in RT recipients with prolonged fever of unknown origin and unusual clinical manifestations, especially those who are unresponsive to antibiotic treatment, a diagnosis of TB should be considered. The interferon gamma release assay and NGS are relatively new detection methods with high sensitivity and specificity; these along with regular, repeated testing by various approaches can aid the early diagnosis of TB.

Chest Infections after Lung Transplantation

Despite substantial progress in the long-term follow-up strategies for lung transplant recipients, morbidity and mortality remain high mostly due to the elevated infectious risk and to the development of chronic lung allograft dysfunction. The high immunosuppressive levels necessary to prevent acute rejection and the graft's constant exposure to the environment come at the high price of frequent infectious complications. Moreover, some infectious agents have been shown to trigger acute rejection or chronic allograft dysfunction. A rapid diagnostic approach followed by an early treatment and follow-up strategy are of paramount importance. They are, however, challenging endeavors due to the vast spectrum of possible pathogens and to the discrete clinical features as a consequence of transplant recipients' impaired immune response. This review proposes a stratified diagnostic strategy, discusses the most relevant pathogens and the corresponding therapeutic approaches while also offering an insight in the infection prevention strategies: vaccination, prophylaxis, preemptive therapy, antibiotic stewardship.

Mycobacterium tuberculosis in solid organ transplant donors and recipients

PURPOSE OF REVIEW

Due to impaired immune response, solid organ transplant (SOT) recipients are susceptible to tuberculosis (TB) and its subsequent morbidity and mortality. Current prevention strategies, diagnostic and treatment approach to TB infection in donors and recipients were reviewed in this article.

RECENT FINDINGS

Screening of latent tuberculosis infection (LTBI) in donors and recipients is the cornerstone of TB-preventive strategy in recipients and requires an assessment of TB risk factors, TB-specific immunity testing, and radiographic evaluation. Interferon-gamma release assay has superseded the tuberculin skin test in LTBI evaluation despite its recognized limitations. LTBI treatment should be offered to transplant candidates and living donors before transplantation and donation, respectively. Diagnosis of TB disease can be challenging because of nonspecific clinical presentation in the recipient and is limited by the sensitivity of current diagnostics. The approach to LTBI and TB disease treatment is similar to the general population, but can be challenging because of potential drug interactions and toxicities.

SUMMARY

The appropriate evaluation of donors and recipients for TB can mitigate posttransplant TB disease. Current approaches to diagnosis and treatment parallels that of immunocompetent hosts. Future research evaluating existing and novel diagnostics and treatment in transplant recipients is needed.

Mycobacteria: Selection of Transplant Candidates and Post-lung Transplant Outcomes

Mycobacterium is a large, clinically relevant bacterial genus made up of the agents of tuberculosis and leprosy and hundreds of species of saprophytic nontuberculous mycobacteria (NTM). Pathogenicity, clinical presentation, epidemiology, and antimicrobial susceptibilities are exceptionally diverse between species. Patients with end-stage lung disease and recipients of lung transplants are at a higher risk of developing NTM colonization and disease and of severe manifestations and outcomes of tuberculosis. Data from the past three decades have increased our knowledge of these infections in lung transplant recipients. Still, there are knowledge gaps to be addressed to further our understanding of risk factors and optimal treatments for mycobacterial infections in this population.

Pulmonary Tuberculosis and Management of Contact Patients in a Department of Nephrology and Kidney Transplantation

OBJECTIVES

To describe the investigation, follow-up, management and outcomes in a cohort of chronic kidney disease and kidney transplant recipients exposed to a case of pulmonary tuberculosis.

METHODS

Contacts were investigated following a concentric circles approach and followed-up according to their level of priority. In those with an evidence of latent tuberculous infection, treatment decision was based on the level of exposure, individual vulnerability, as well as the results of an interferon-gamma release assay.

RESULTS

130 patients with chronic kidney disease and 180 kidney transplant recipients were identified as contacts and followed-up over a two-year period.Only few vulnerable high-priority contacts received an anti-tuberculosis treatment, including the 2 (100%)highly exposed patients in circle 1, 11/78(14.1%)chronic kidney disease patients and 4/142 (2.8%) kidney transplant recipients in circle 2, and10/52 (19.2%) chronic kidney disease patients and 2/36 (5.6%) kidney transplant recipients in circle 3;all having a positive interferon-gamma release assay result. No incident case of tuberculosis disease occurred.

CONCLUSIONS

These findings suggest that latent tuberculosis treatment, as recommended in European guidelines, might be reasonably avoided in vulnerable high-priority contacts of circle 2 with a negative interferon-gamma release assay in countries with low prevalence of tuberculosis.

Donor-Derived Tuberculosis: A Case Report and the Role of Communication Gaps in Transplantation Safety

Donor-derived tuberculosis (DD-TB) accounts for less than 5% of TB cases and is considered a rare event. In the transplant setting, the frequency of active TB is estimated to be 20 to 74 times higher than that in the general population, and it is associated with high mortality. In this context, the main strategy to minimize the risk of DD transmission is to identify high-risk donors. Despite screening recommendations, failures may result in a breakdown of safety that ends in the transmission of potentially fatal diseases. This report describes a case of DD-TB and emphasizes communication gaps that may occur between organ procurement organizations and transplant centers. Failure in reporting results, lack of exchanging information regarding recipients from the same donor, and inefficient communication between organ procurement organizations and transplant centers are lacks that may be prevented by a more efficient approach towards screening protocols and communication.

Multifocal skeletal tuberculosis with mycobacteremia after kidney transplantation: A case report

Solid organ transplant recipients have a higher risk of active Mycobacterium tuberculosis infection (TB) compared to the general population. Recognized risk factors are immunosuppressant use, graft dysfunction, diabetes mellitus, liver disease caused by the hepatitis C virus, and co-infections by other opportunists. Most of the active TB cases reported in solid organ transplant recipients occur in kidney transplant patients, especially if they come from M tuberculosis-endemic areas. Extrapulmonary and disseminated TB are among the wide spectrum of clinical presentations found, but the lungs are the most common organ affected. Disseminated disease occurs in up to a third of the affected population, however, multifocal osteoarticular TB with mycobacteremia is unusual. We report the case of a kidney transplant patient with disseminated M tuberculosis infection, who presented with multifocal skeletal TB.

Successful Lobar Lung Transplant From a Marginal Deceased Donor With a History of Treated Pulmonary Tuberculosis: A Case Report

The shortage of available donor lungs is a continuing clinical problem. Lobar lung transplant and the extension of donor lung criteria may expand the pool of donor lungs. We here report a case of lobar lung transplant from a marginal deceased donor with bronchiectasis and fibrosis at the left upper lobe and a history of treated pulmonary tuberculosis. Our experience with this case suggests that a lobar lung transplant can be considered not only for size mismatches but also for use of locally damaged lungs. In addition, lungs from a donor who received treatment for pulmonary tuberculosis may be feasible for transplant with chemoprophylaxis for latent tuberculosis infection. Our current case indicates one possible option to overcome the persistent shortage of available donor lungs.

Risk stratification and management of QuantiFERON-positive solid-organ living donors

PURPOSE OF REVIEW

Donor-derived disease with Mycobacterium tuberculosis (MTB) is likely to become more common as donor pools expand due to increasing transplant volume coupled with patterns of migration and global mobility. Our article reviews the current literature and provides a rational approach for clinicians managing the scenario of a living donor who has epidemiologic risk factors for tuberculosis exposure.

RECENT FINDINGS

Tuberculous bacilli, formerly thought to exist latently only in pulmonary granulomas, are now known reside dormant in nonpulmonary organs. Kidney and liver grafts are thus vectors for donor transmitted MTB disease. Donors with elevated risk for latent MTB disease can be identified with tuberculin skin testing or IFN-γ release assay screening in combination with a thorough history to identify risk factors for latent disease.

SUMMARY

Living donors with an elevated risk for prior MTB exposure provide an opportunity to treat latent disease prior to organ procurement and reduce the risk of donor transmitted disease and secondary morbidity. Improved identification of these high-risk donors can reduce both the incidence of posttransplant MTB disease and the risk of allograft compromise associated with treatment of latent and active disease in posttransplant recipients.

Tuberculosis in Pediatric Solid Organ and Hematopoietic Stem Cell Recipients

Children undergoing solid organ and hematopoietic stem cell transplantation are at high risk of morbidity and mortality from tuberculosis (TB) disease in the post-transplant period. Treatment of TB infection and disease in the post-transplant setting is complicated by immunosuppression and drug interactions. There are limited data that address the unique challenges for the management of TB in the pediatric transplant population. This review presents the current understanding of the epidemiology, clinical presentation, diagnosis, management, and prevention for pediatric transplant recipients with TB infection and disease. Further studies are needed to improve diagnosis of TB and optimize treatment outcomes for these patients.

Primary tuberculosis of the graft masquerading pyogenic liver abscess in a pediatric liver recipient

Primary tuberculosis (TB) of the graft presenting as multiple liver abscesses is previously unreported. A 14-month-old male child in the early post liver transplant (LT) period presented with high-grade fever spikes and on evaluation was found to have multiple pyogenic liver abscesses (PLA) in the CT abdomen. His fever was not responding to intravenous antibiotics and liver biopsy was done which showed numerous acid fast bacilli. Genetic analysis confirmed the bacilli as Mycobacterium tuberculosis (MTB). Timely diagnosis and prompt introduction of antituberculosis therapy were lifesaving.

Tuberculosis transmission across three states: The story of a solid organ donor born in an endemic country, 2018

Transmission of tuberculosis (TB) from a deceased solid organ donor to recipients can result in severe morbidity and mortality. In 2018, four solid organ transplant recipients residing in three states but sharing a common organ donor were diagnosed with TB disease. Two recipients were hospitalized and none died. The organ donor was born in a country with a high incidence of TB and experienced 8 weeks of headache and fever prior to death, but was not tested for TB during multiple hospitalizations or prior to organ procurement. TB isolates of two organ recipients and a close contact of the donor had identical TB genotypes and closely related whole-genome sequencing results. Donors with risk factors for TB, in particular birth or residence in countries with a higher TB incidence, should be carefully evaluated for TB.

Review of the impact of donor characteristics on pediatric heart transplant outcomes

Heart transplantation (HTx) is a treatment option for end-stage heart failure in children. HTx is limited by the availability and acceptability of donor hearts. Refusal of donor hearts has been reported to be common with reasons for refusal including preexisting donor characteristics. This review will focus on the impact of donor characteristics and comorbidities on outcomes following pediatric HTx. A literature review was performed to identify articles on donor characteristics and comorbidities and pediatric HTx outcomes. There are many donor characteristics to consider when accepting a donor heart. Weight-based matching is the most common form of matching in pediatric HTx with a donor-recipient weight ratio between 0.7 and 3 having limited impact on outcomes. From an age perspective, donors <50 years can be carefully considered, but the impact of ischemic time needs to be understood. To increase the donor pool, with minimal impact on outcomes, ABO-incompatible donors should be considered in patients that are eligible. Other factors to be considered when accepting an organ is donor comorbidities. Little is known about donor comorbidities in pediatric HTx, with most of the data available focusing on infections. Being aware of the potential infections in the donor, understanding the testing available and risks of transmission, and treatment options for the recipient is essential. There are a number of donor characteristics that potentially impact outcomes following pediatric HTx, but these need to be taken into consideration along with their interactions with recipient factors when interpreting the outcomes following HTx.

Management and prophylaxis of bacterial and mycobacterial infections among lung transplant recipients

Bacterial and mycobacterial infections are associated with morbidity and mortality in lung transplant recipients. Infectious complications are categorized by timing post-transplant: <1, 1–6, and >6 months. The first month post-transplant is associated with the highest risk of infection. During this period, infections are most commonly healthcare-associated, and include infections related to surgical complications. The lungs and bloodstream are common sites of infections. Common healthcare-associated organisms include methicillin-resistant Staphylococcus aureus (MRSA), Gram-negative bacilli such as Pseudomonas aeruginosa, and Clostridioides difficile. More than 1-month post-transplant, opportunistic infections can occur. Tuberculosis occurs in 0.8–10% of lung transplant recipients which reflects variation in background prevalence. The majority of post-transplant tuberculosis stems from reactivation of untreated or undiagnosed latent tuberculosis. Most post-transplant tuberculosis occurs in the lungs and develops within a year of transplant. Non-tuberculous mycobacteria commonly colonize the lungs of lung transplant candidates and are often hard to eradicate even with prolonged courses of antimycobacterial agents. Drug interactions between antimycobacterial agents and calcineurin and mTOR inhibitors also complicates treatment post-transplant. Given that infection adversely impacts outcomes after lung transplant, and that anti-infective therapy is often less effective after transplant, infection prevention is key to long-term success. A comprehensive approach that includes pre-transplant evaluation, perioperative prophylaxis, long-term antimicrobial prophylaxis, immunization, and safer living at home and in the community, should be employed to minimize the risk of infection.

Treatment of latent tuberculosis infection with short-course regimens in potential living kidney donors

BACKGROUND

Treatment data for latent tuberculosis infection (LTBI) among potential living kidney donors are scarce.

METHODS

This retrospective study was performed to evaluate the prevalence of positive QuantiFERON-TB Gold In-Tube (QFT-GIT) among potential living kidney donors that were screened from 2009 to 2017. We investigated if there was any difference in the time to donation between QFT-GIT-positive and QFT-GIT-negative donors. We assessed the regimens used to treat LTBI and whether the recipients of QFT-GIT-positive donors developed active tuberculosis (TB).

RESULTS

Forty out of 427 (9%) potential living kidney donors had a positive QFT-GIT. QFT-GIT-positive donors were as likely as negative donors to undergo donation (30 [75%] vs 315 [81%], P = .33). The time from QFT-GIT testing to donation was longer among QFT-GIT-positive donors (median 221 days [range: 4-1139] vs 86 days [range: 3-1887], P = .001). Twelve-week rifapentine (RPT)/Isoniazid (INH) was the most common treatment used and was not associated with significant adverse reactions. There was a trend toward longer time to donation among QFT-GIT-positive donors who were treated for LTBI compared with QFT-GIT-positive donors who were not (252 days [range: 88-1139] vs 95 days [range: 4-802], P = .05). Twenty-nine recipients of QFT-GIT-positive living kidney donors were evaluated. Eleven of these recipients received kidneys from donors that were not treated for LTBI. Two of these recipients were treated with INH post-transplantation.

CONCLUSIONS

The time from QFT-GIT testing to donation was longer among QFT-GIT-positive donors. The short-course regimens appear to be excellent options for LTBI treatment among living kidney donors and avoid delaying organ donation further.

Prevention and treatment of tuberculosis in solid organ transplant recipients

Introduction: Tuberculosis (TB) in solid organ transplant (SOT) recipients is associated with significant morbidity and mortality. Its management in transplant recipients is difficult and highly complex, given the underlying immunosuppression and the risks of drug-drug interactions imposed by immunosuppressive drugs that are needed to maintain the transplant allograft.Areas covered: We provide a brief review of TB in SOT and discuss the clinical indications, mechanisms of action and drug resistance, drug-drug interactions, and adverse effects of anti-TB drugs. We provide a summary of recent clinical trials, which serve as the foundation for current recommendations. We further include relevant updates on new agents being evaluated for clinical use in TB management.Expert commentary: TB causes significant morbidity in SOT recipients. The drugs used in the treatment for latent TB and active disease in SOT are similar to the regimens used in the general population. However, TB disease in transplant recipients is more difficult to manage because of the potential for hepatotoxicity and the complex drug-drug interactions with immunosuppressive drugs. We believe that alternative regimens suited for the vulnerable transplant population, and more therapeutic drug options are needed given the adverse toxicities associated with currently approved anti-TB drugs.

Is hospital-acquired pneumonia different in transplant recipients?

Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) are serious complications in transplant patients. The aim of this review is to summarize the evidence regarding nosocomial pneumonia in transplant recipients, including HAP in non-ventilated patients and VAP, and to identify future directions for improvement.A comprehensive literature search in the PubMed/MEDLINE database was performed. Articles written in English and published between 1990 and November 2018 were included. HAP/VAP in transplant patients usually occurs early post-transplant, particularly during neutropenia in haematopoietic stem cell transplant recipients. Bacteria are the leading cause of nosocomial pneumonia for both immunocompetent and transplant recipients, being Gram negative organisms, and especially Pseudomonas aeruginosa, highly prevalent. Multidrug-resistant bacteria are of special concern. Pneumonia in the transplant setting may be caused by opportunistic pathogens, and the differential diagnosis needs to be extended to other non-infectious complications. The most relevant opportunistic pathogens are Aspergillus fumigatus, Pneumocystis jirovecii and cytomegalovirus. Nevertheless, they are an exceptional cause of nosocomial pneumonia, and usually occur in severely immunosuppressed patients not receiving antimicrobial prophylaxis. Performing bronchoalveolar lavage may improve the rate of aetiological diagnosis, leading to a change in therapeutic management and improved outcomes. The optimal length of antibiotic therapy for bacterial HAP/VAP has not been well defined, but it should perhaps be longer than in the general population. Mortality associated with HAP/VAP is high. HAP/VAP in transplant patients is frequent and is associated with increased mortality. There is room for improvement in gaining knowledge about the management of HAP/VAP in this population.

Mycobacteria-Specific T Cells May Be Expanded From Healthy Donors and Are Near Absent in Primary Immunodeficiency Disorders

Mycobacterial Infections can be severe in patients with T-cell deficiency or phagocyte disorders, and treatment is frequently complicated by antimicrobial resistance. Restoration of T-cell immunity via stem cell transplantation facilitates control of mycobacterial infections, but presence of active infections during transplantation is associated with a higher risk of mortality. Adoptive T cell immunotherapy has been successful in targeting viruses, but has not been attempted to treat mycobacterial infections. We sought to expand and characterize mycobacterial-specific T-cells derived from healthy donors in order to determine suitability for adoptive immunotherapy. Mycobacteria-specific T-cells (MSTs) were generated from 10 healthy donors using a rapid ex vivo expansion protocol targeting five known mycobacterial target proteins (AG85B, PPE68, ESXA, ESXB, and ADK). MSTs were compared to T-cells expanded from the same donors using lysate from M. tuberculosis or purified protein derivative from M. avium (sensitin). MST expansion from seven patients with primary immunodeficiency disorders (PID) and two patients with IFN-γ autoantibodies and invasive M. avium infections. MSTs expanded from healthy donors recognized a median of 3 of 5 antigens, with production of IFN-γ, TNF, and GM-CSF in CD4⁺ T cells. Comparison of donors who received BCG vaccine (n = 6) to those who did not (n = 4) showed differential responses to PPE68 (p = 0.028) and ADK (p = 0.015) by IFN-γ ELISpot. MSTs expanded from lysate or sensitin also recognized multiple mycobacterial antigens, with a statistically significant differences noted only in the response to PPE68 (p = 0.016). MSTs expanded from patients with primary immunodeficiency (PID) and invasive mycobacterial infections showed activity against mycobacterial antigens in only two of seven subjects, whereas both patients with IFN-γ autoantibodies recognized mycobacterial antigens. Thus, MSTs can be generated from donors using a rapid expansion protocol regardless of history of BCG immunization. Most tested PID patients had no detectable T-cell immunity to mycobacteria despite history of infection. MSTs may have clinical utility for adoptive immunotherapy in T-cell deficient patients with invasive mycobacterial infections.