Infections and organ transplantation: new challenges for prevention and treatment--a colloquium. Transplantation. 2012;93:S4-S39. [PMID: 22374265 DOI: 10.1097/tp.0b013e3182481347]

Biofire pneumonia panel in lung donors: faster detection but limited pathogens

BACKGROUND

Culture of bronchoalveolar lavage (BAL) specimens takes time to report. We tested whether a molecular diagnostic test could accelerate donor lung assessment and treatment.

METHODS

We compared BioFire Film Array Pneumonia Panel (BFPP) with standard of care (SOC) tests on lung allograft samples at three time points: (1) donor BAL at organ recovery, (2) donor bronchial tissue and airway swab at implantation, and (3) first recipient BAL following lung implantation. Primary outcomes were the difference in time to result (Wilcoxon signed-ranked tests) and the agreement in results between BFPP and SOC assays (Gwet's agreement coefficient).

RESULTS

We enrolled 50 subjects. In donor lung BAL specimens, BFPP detected 52 infections (14 out of 26 pathogens in the panel). Viral and bacterial BFPP results were reported 2.4 h (interquartile range, IQR 2.0-6.4) following BAL versus 4.6 h (IQR 1.9-6.0, p = 0.625) for OPO BAL viral SOC results and 66 h (IQR 47-87, p < .0001) for OPO BAL bacterial SOC results. Although there was high overall agreement of results between BAL-BFPP versus OPO BAL-SOC tests (Gwet's AC p < .001 for all), the level of agreement differed among 26 pathogens designed in BFPP and differed by types of specimens. BFPP could not detect many infections identified by SOC assays.

CONCLUSIONS

BFPP decreased time to detection of lung pathogens among donated lungs, but it cannot replace SOC tests due to the limited number of pathogens in the panel.

Solid Organ Transplantation From Deceased Donors With Infective Endocarditis: The UK Experience

BACKGROUND

There is little evidence regarding the use of organs from deceased donors with infective endocarditis. We performed a retrospective analysis of the utilization, safety, and long-term survival of transplants from donors with infective endocarditis in the United Kingdom.

METHODS

We studied deceased donor transplants over an 18-y period (2001-2018) using data from the UK Transplant Registry. We estimated the risk of infection transmission, defined as a microbiological isolate in the recipient matching the causative organism in the donor in the first 30 days posttransplant. We examined all-cause allograft failure up to 5 years in kidney and liver recipients, comparing transplants from donors with endocarditis with randomly selected matched control transplants.

RESULTS

We studied 88 transplants from 42 donors with infective endocarditis. We found no cases of infection transmission. There was no difference in allograft failure between transplants from donors with infective endocarditis and matched control transplants, among either kidney (hazard ratio, 1.48; 95% CI, 0.66-3.34) or liver (hazard ratio, 1.14; 95% CI, 0.54-2.41) recipients. Compared with matched controls, donors with infective endocarditis donated fewer organs (2.3 versus 3.2 organs per donor; P < 0.001) and were less likely to become kidney donors (odds ratio, 0.29; 95% CI, 0.16-0.55).

CONCLUSIONS

We found acceptable safety and long-term allograft survival in transplants from selected donors with infective endocarditis in the United Kingdom. This may have implications for donor selection and organ utilization.

CRISPR-Cas9-Edited Tacrolimus-Resistant Antiviral T Cells for Advanced Adoptive Immunotherapy in Transplant Recipients

Viral infections, such as with cytomegalovirus (CMV), remain a major risk factor for mortality and morbidity of transplant recipients because of their requirement for lifelong immunosuppression (IS). Antiviral drugs often cause toxicity and sometimes fail to control disease. Thus, regeneration of the antiviral immune response by adoptive antiviral T cell therapy is an attractive alternative. Our recent data, however, show only short-term efficacy in some solid organ recipients, possibly because of malfunction in transferred T cells caused by ongoing IS. We developed a vector-free clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9-based good manufacturing practice (GMP)-compliant protocol that efficiently targets and knocks out the gene for the adaptor protein FK506-binding protein 12 (FKBP12), required for the immunosuppressive function of tacrolimus. This was achieved by transient delivery of ribonucleoprotein complexes into CMV-specific T cells by electroporation. We confirmed the tacrolimus resistance of our gene-edited T cell products in vitro and demonstrated performance comparable with non-tacrolimus-treated unmodified T cells. The alternative calcineurin inhibitor cyclosporine A can be administered as a safety switch to shut down tacrolimus-resistant T cell activity in case of adverse effects. Furthermore, we performed safety assessments as a prerequisite for translation to first-in-human applications.

Routine Bile Culture From Liver Donors as Screening of Donor-Transmitted Infections in Liver Transplantation

Bacterial infections are an important threat in the early post-liver transplantation period. Donor-transmitted infections, although rare, can have high mortality. The utility of routine culture from the donor bile duct as screening of donor-transmitted infection has not been evaluated. We performed a retrospective study of 200 consecutive liver transplants between 2010 and 2015. Demographic, clinical, and microbiological data were collected from the recipients' medical records. Clinical data included pretransplantation, perioperative, and posttransplantation information (until 30 days after the procedure). The 3-month patient survival and/or retransplantation were recorded. A total of 157 samples from the donor bile duct were collected and cultured. Only 8 were positive. The microorganisms isolated were as follows: Klebsiella pneumoniae, n = 2; Escherichia coli, n = 1; Enterobacter cloacae, n = 1; Streptococcus anginosus, n = 1; Streptococcus sp., n = 1; multiple gram-negative bacilli, n = 1; and polymicrobial, n = 1. All of the microorganisms were susceptible to the antibiotic prophylaxis administered. During the first month after transplantation, 81 recipients developed 131 infections. Only 1 of these recipients had a donor with a positive bile culture, and none of the infections were due to the microorganism isolated in the donor's bile. The 3-month overall survival was 89.5%, and there were no differences between recipients with positive donor bile cultures and those with negative donor bile cultures (87.5% versus 89.26%; P > 0.99). Routine testing of donor bile cultures does not predict recipients' infection or survival after liver transplantation and should not be recommended.

Comprehensive Characterization of a Next-Generation Antiviral T-Cell Product and Feasibility for Application in Immunosuppressed Transplant Patients

Viral infections have a major impact on morbidity and mortality of immunosuppressed solid organ transplant (SOT) patients because of missing or failure of adequate pharmacologic antiviral treatment. Adoptive antiviral T-cell therapy (AVTT), regenerating disturbed endogenous T-cell immunity, emerged as an attractive alternative approach to combat severe viral complications in immunocompromised patients. AVTT is successful in patients after hematopoietic stem cell transplantation where T-cell products (TCPs) are manufactured from healthy donors. In contrast, in the SOT setting TCPs are derived from/applied back to immunosuppressed patients. We and others demonstrated feasibility of TCP generation from SOT patients and first clinical proof-of-concept trials revealing promising data. However, the initial efficacy is frequently lost long-term, because of limited survival of transferred short-lived T-cells indicating a need for next-generation TCPs. Our recent data suggest that Rapamycin treatment during TCP manufacture, conferring partial inhibition of mTOR, might improve its composition. The aim of this study was to confirm these promising observations in a setting closer to clinical challenges and to deeply characterize the next-generation TCPs. Using cytomegalovirus (CMV) as model, our next-generation Rapamycin-treated (Rapa-)TCP showed consistently increased proportions of CD4⁺ T-cells as well as CD4⁺ and CD8⁺ central-memory T-cells (T_CM). In addition, Rapamycin sustained T-cell function despite withdrawal of Rapamycin, showed superior T-cell viability and resistance to apoptosis, stable metabolism upon activation, preferential expansion of T_CM, partial conversion of other memory T-cell subsets to T_CM and increased clonal diversity. On transcriptome level, we observed a gene expression profile denoting long-lived early memory T-cells with potent effector functions. Furthermore, we successfully applied the novel protocol for the generation of Rapa-TCPs to 19/19 SOT patients in a comparative study, irrespective of their history of CMV reactivation. Moreover, comparison of paired TCPs generated before/after transplantation did not reveal inferiority of the latter despite exposition to maintenance immunosuppression post-SOT. Our data imply that the Rapa-TCPs, exhibiting longevity and sustained T-cell memory, are a reasonable treatment option for SOT patients. Based on our success to manufacture Rapa-TCPs from SOT patients under maintenance immunosuppression, now, we seek ultimate clinical proof of efficacy in a clinical study.

Donor-derived infections: 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 will review the current state of the art of donor-derived infections. Specifically, the guideline will summarize standardized definitions and approaches to defining imputability, updated data on the epidemiology of donor-derived infections, and approaches to risk mitigation against transmission of infections. This update will additionally provide guidance on the use of HIV+ donors in HIV+ recipients, the use of HCV-viremic donors in non-viremic recipients, donors with endemic infections, and donors with bacteremia, meningitis, and encephalitis. Lastly, the guidance will summarize an approach to recipients with a suspected donor-derived infection.

Outcome of pediatric heart transplantation in blood culture positive donors in the United States

Active donor infection at the time of organ procurement poses a potential infection risk and may increase post-transplant morbidity and mortality in recipients. Our hypothesis was that pediatric heart transplant recipients from blood culture positive donors (BCPD) would have increased morbidity and mortality compared to non-blood culture positive donors (NBCPD). A retrospective analysis of pediatric heart transplant recipients using the organ procurement and transplant network (OPTN) between 1987 and 2015 was conducted. Recipient as well as donor data were analyzed. Propensity score matching with 1:2 ratios was performed for recipient variables. Post-transplant morbidity and mortality were compared for recipients of BCPD and NBCPD. Among 9618 heart transplant recipients, 450 (4.7%) were from culture positive donors. Recipients of BCPD had longer duration of listing as Status 1; diagnosis of congenital heart disease or restrictive cardiomyopathy and required support (IV inotropes, Inhaled NO and LVAD) prior to transplant. Post-transplant survival between the 2 groups was not different. Propensity-matched recipients had similar length of stay; stroke rate; need for dialysis; pacemaker implantation and treated rejection episodes in the first year post-transplant. Careful acceptance of BCPD may have the potential to increase availability of donor hearts in the pediatric population.

Donor-Transmitted Bacterial Infection in Deceased Donor Liver Transplantation: Experience of Southern Taiwan Medical Center

BACKGROUND

Bacterial Infection is the most important source of mortality and morbidity in liver transplantation recipients. Donor transmitted bacterial infection is rare but one of the most important infection sources. This kind of infection is difficult to identify, causing treatment dilemma.

PATIENTS AND METHODS

In this article, we retrospectively reviewed our deceased donor liver transplants performed from January 2014 to December 2016. Forty-two recipients in Kaohsiung Chang Gung Memorial Hospital receiving liver grafts from 35 deceased liver donors were evaluated. The demography, donor transmitted infection, and outcomes were evaluated.

RESULT

Two patients had probable donor transmitted bacterial infection and 1 patient died of suspected transmitted infection.

CONCLUSION

Early identification of donor infection and adequate antibiotic treatment for the donor and recipient are the keys to preventing donor transmitted bacterial infection. Donor infection is not an absolute contraindication for organ donation in the area of organ shortage. Organ procurement organizations or similar authorities may establish the platform for sharing the data about donor and recipient infections.

Donor-derived infections in solid organ transplant patients: toward a holistic approach

PURPOSE OF REVIEW

Solid organ demand far exceeds organ supply. Strategies to increase the donor pool include the liberalization of selection criteria without increasing the risk of unexpected donor-derived infection (DDI), a rare complication of transplantation carrying high morbidity and mortality. We review the challenging aspects in the prevention of DDI, focusing on the complexities of data sharing and efficient communication and the role infectious diseases specialists play in the process.

RECENT FINDINGS

Advances in donor screening, transmission recognition and reporting allow for a better estimation of the risk of DDI. However, there is great variability in the frequency and methods with which organ procurement organizations report transmission events.Moreover, the Scientific Registry of Transplant Recipients provides limited donor and recipient outcome infectious diseases related data. Infectious disease contribution to the allocation process has been found to improve organ donation efficiency and communication between involved parties. Although communication gaps are strongly associated with infection transmission (relative risk 2.36%, confidence interval 1.48-3.78), effective communication minimizes or prevents infection in transplant recipients (X(1) 13.13, P = 0.0003).

SUMMARY

Prospective research is still required to define optimal screening protocols and further prevent transmission of infection. A holistic approach is likely to result in enhanced transplantation safety. Toward this goal, development of standards of investigation; improvement in reporting and data sharing; and strategies ensuring coordinated and rapid communication among parties involved in the allocation process need to be pursued.

Guidelines for the assessment and acceptance of potential brain-dead organ donors

Organ transplantation is the only alternative for many patients with terminal diseases. The increasing disproportion between the high demand for organ transplants and the low rate of transplants actually performed is worrisome. Some of the causes of this disproportion are errors in the identification of potential organ donors and in the determination of contraindications by the attending staff. Therefore, the aim of the present document is to provide guidelines for intensive care multi-professional staffs for the recognition, assessment and acceptance of potential organ donors.

Successful Kidney and Lung Transplantation From a Deceased Donor With Blunt Abdominal Trauma and Intestinal Perforation

The number of organ donors is limited by many contraindications for donation and poor quality of potential organ donors. Abdominal infection is a generally accepted contraindication for donation of abdominal organs. We present a 43-year-old man with lethal brain injury, blunt abdominal trauma, and intestinal perforation. After withdrawal of life-sustaining treatment and circulatory arrest, a minilaparotomy confirmed abdominal contamination with intestinal content. After closure of the abdomen, organs were preserved with in situ preservation with an aortic cannula inserted via the femoral artery. Thereafter, the kidneys were procured via bilateral lumbotomy to reduce the risk of direct bacterial contamination; lungs were retrieved following a standard practice. There was no bacterial or fungal growth in the machine preservation fluid of both kidneys. All organs were successfully transplanted, without postoperative infection, and functioned well after 6 months. We hereby show that direct contamination of organs can be avoided with the use of in situ preservation and retroperitoneal procurement. Intestinal perforation is not an absolute contraindication for donation, although the risk of bacterial or fungal transmission has to be evaluated per case.

Outcome of Transplantation Using Organs From Donors Infected or Colonized With Carbapenem-Resistant Gram-Negative Bacteria

Donor-derived infections due to multidrug-resistant bacteria are a growing problem in solid organ transplantation, and optimal management options are not clear. In a 2-year period, 30/214 (14%) recipients received an organ from 18/170 (10.5%) deceased donors with infection or colonization caused by a carbapenem-resistant gram-negative bacteria that was unknown at the time of transplantation. Among them, 14/30 recipients (47%) received a transplant from a donor with bacteremia or with infection/colonization of the transplanted organ and were considered at high risk of donor-derived infection transmission. The remaining 16/30 (53%) recipients received an organ from a nonbacteremic donor with colonization of a nontransplanted organ and were considered at low risk of infection transmission. Proven transmission occurred in 4 of the 14 high-risk recipients because donor infection was either not recognized, underestimated, or not communicated. These recipients received late, short or inappropriate posttransplant antibiotic therapy. Transmission did not occur in high-risk recipients who received appropriate and prompt antibiotic therapy for at least 7 days. The safe use of organs from donors with multidrug-resistant bacteria requires intra- and inter-institutional communication to allow appropriate management and prompt treatment of recipients in order to avoid transmission of infection.

Selecting suitable solid organ transplant donors: Reducing the risk of donor-transmitted infections

Selection of the appropriate donor is essential to a successful allograft recipient outcome for solid organ transplantation. Multiple infectious diseases have been transmitted from the donor to the recipient via transplantation. Donor-transmitted infections cause increased morbidity and mortality to the recipient. In recent years, a series of high-profile transmissions of infections have occurred in organ recipients prompting increased attention on the process of improving the selection of an appropriate donor that balances the shortage of needed allografts with an approach that mitigates the risk of donor-transmitted infection to the recipient. Important advances focused on improving donor screening diagnostics, using previously excluded high-risk donors, and individualizing the selection of allografts to recipients based on their prior infection history are serving to increase the donor pool and improve outcomes after transplant. This article serves to review the relevant literature surrounding this topic and to provide a suggested approach to the selection of an appropriate solid organ transplant donor.

Central nervous system syndromes in solid organ transplant recipients

Solid organ transplant recipients have a high incidence of central nervous system (CNS) complications, including both focal and diffuse neurologic deficits. In the immunocompromised host, the initial clinical evaluation must focus on both life-threatening CNS infections and vascular or anatomic lesions. The clinical signs and symptoms of CNS processes are modified by the immunosuppression required to prevent graft rejection. In this population, these etiologies often coexist with drug toxicities and metabolic abnormalities that complicate the development of a specific approach to clinical management. This review assesses the multiple risk factors for CNS processes in solid organ transplant recipients and establishes a timeline to assist in the evaluation and management of these complex patients.

Bacterial infection after liver transplantation

Infectious complications are major causes of morbidity and mortality after liver transplantation, despite recent advances in the transplant field. Bacteria, fungi, viruses and parasites can cause infection before and after transplantation. Among them, bacterial infections are predominant during the first two months post-transplantation and affect patient and graft survival. They might cause surgical site infections, including deep intra-abdominal infections, bacteremia, pneumonia, catheter-related infections and urinary tract infections. The risk factors for bacterial infections differ between the periods after transplant, and between centers. Recently, the emergence of multi-drug resistant bacteria is great concern in liver transplant (LT) patients. The instructive data about effects of infections with extended-spectrum beta lactamase producing bacteria, carbapenem-resistant gram-negative bacteria, and glycopeptide-resistant gram-positive bacteria were reported on a center-by-center basis. To prevent post-transplant bacterial infections, proper strategies need to be established based upon center-specific data and evidence from well-controlled studies. This article reviewed the recent epidemiological data, risk factors for each type of infections and important clinical issues in bacterial infection after LT.

Spectrum of pathogens in native liver, bile, and blood during pediatric liver transplantation

During LTX, there may be a risk that pathogens of the native liver are released into the systemic circulation. No investigations on incidence/spectrum of pathogens in native livers have been published. We hypothesized that pathogens are found in the native liver of a large proportion of pediatric patients during LTX and investigated the microbiology of native livers. These data may help optimize antibiotic therapy. Twenty-two consecutive pediatric patients (median age 14 months, range, 5 months-15 yr) receiving LTX in our department from October 2010 to October 2011 were included in this prospective study. Tissue and bile were collected from the explanted liver and were cultivated on different media. All liver tissues were investigated using a broad-range PCR (SepsiTest(®)). In 16 patients, blood cultures were collected post-transplantation. Eleven patients (50%) had at least one pathogen detected; nine of these patients had an underlying diagnosis of biliary atresia. SepsiTest(®) was positive in seven patients. In four patients it was the only test detecting any pathogen. In detail, the positivity rate for liver tissue in all patients was 41% (n = 9); for bile 25% (n = 3); and for blood 25% (n = 4). Thirteen different pathogens (69% bacterial, 31% fungal) were isolated. A highly-sensitive broad-range PCR appears to be an effective method to detect pathogens in native livers of patients undergoing LTX. A high number and variety of microbes, including a high proportion of fungal pathogens, were detected.

Cryptococcal infections: changing epidemiology and implications for therapy

Although the incidence of HIV-associated cryptococcosis has decreased in developed countries since the introduction of antiretroviral therapy, this disease continues to cause significant morbidity and mortality in sub-Saharan Africa among patients with AIDS. Important strides have been made in an attempt to decrease the burden of disease, particularly the development of the lateral flow assay cryptococcal antigen (LFA CrAg) as a diagnostic tool in resource-limited settings, coupled with the introduction of pre-emptive treatment with fluconazole for HIV-positive patients at risk for cryptococcosis with a positive LFA CrAg. Among solid organ transplant recipients, recent prospective studies have identified cryptococcosis as the third most common invasive fungal infection, and progress is being made toward earlier diagnosis and more effective therapy. Finally, the Cryptococcus gattii outbreak in British Columbia, Canada and the US Pacific Northwest is providing important new insights into the emergence of this pathogen in geographic areas previously considered low risk for acquisition of infection. Understanding the similarities and differences among C. gattii and C. neoformans infections will provide critical insights into the behavior of these organisms in the human host. Both pathogens affect immunocompetent and immunosuppressed hosts, causing pulmonary, central nervous system and widely disseminated infections. Treatment recommendations in the future will necessarily take into account the site of infection, clinical severity of the infection, Cryptococcus species, host immune status and economic resources.

Serologic vaccination response after solid organ transplantation: a systematic review

BACKGROUND

Infectious diseases after solid organ transplantation (SOT) are one of the major complications in transplantation medicine. Vaccination-based prevention is desirable, but data on the response to active vaccination after SOT are conflicting.

METHODS

In this systematic review, we identify the serologic response rate of SOT recipients to post-transplantation vaccination against tetanus, diphtheria, polio, hepatitis A and B, influenza, Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitides, tick-borne encephalitis, rabies, varicella, mumps, measles, and rubella.

RESULTS

Of the 2478 papers initially identified, 72 were included in the final review. The most important findings are that (1) most clinical trials conducted and published over more than 30 years have all been small and highly heterogeneous regarding trial design, patient cohorts selected, patient inclusion criteria, dosing and vaccination schemes, follow up periods and outcomes assessed, (2) the individual vaccines investigated have been studied predominately only in one group of SOT recipients, i.e. tetanus, diphtheria and polio in RTX recipients, hepatitis A exclusively in adult LTX recipients and mumps, measles and rubella in paediatric LTX recipients, (3) SOT recipients mount an immune response which is for most vaccines lower than in healthy controls. The degree to which this response is impaired varies with the type of vaccine, age and organ transplanted and (4) for some vaccines antibodies decline rapidly.

CONCLUSION

Vaccine-based prevention of infectious diseases is far from satisfactory in SOT recipients. Despite the large number of vaccination studies preformed over the past decades, knowledge on vaccination response is still limited. Even though the protection, which can be achieved in SOT recipients through vaccination, appears encouraging on the basis of available data, current vaccination guidelines and recommendations for post-SOT recipients remain poorly supported by evidence. There is an urgent need to conduct appropriately powered vaccination trials in well-defined SOT recipient cohorts.