Unrecognized pretransplant and donor‐derived cryptococcal disease in organ transplant recipients

Global guideline for the diagnosis and management of cryptococcosis: an initiative of the ECMM and ISHAM in cooperation with the ASM

Cryptococcosis is a major worldwide disseminated invasive fungal infection. Cryptococcosis, particularly in its most lethal manifestation of cryptococcal meningitis, accounts for substantial mortality and morbidity. The breadth of the clinical cryptococcosis syndromes, the different patient types at-risk and affected, and the vastly disparate resource settings where clinicians practice pose a complex array of challenges. Expert contributors from diverse regions of the world have collated data, reviewed the evidence, and provided insightful guideline recommendations for health practitioners across the globe. This guideline offers updated practical guidance and implementable recommendations on the clinical approaches, screening, diagnosis, management, and follow-up care of a patient with cryptococcosis and serves as a comprehensive synthesis of current evidence on cryptococcosis. This Review seeks to facilitate optimal clinical decision making on cryptococcosis and addresses the myriad of clinical complications by incorporating data from historical and contemporary clinical trials. This guideline is grounded on a set of core management principles, while acknowledging the practical challenges of antifungal access and resource limitations faced by many clinicians and patients. More than 70 societies internationally have endorsed the content, structure, evidence, recommendation, and pragmatic wisdom of this global cryptococcosis guideline to inform clinicians about the past, present, and future of care for a patient with cryptococcosis.

Unusual presentation of disseminated cryptococcal infection complicated by myocarditis in a heart transplant recipient

BACKGROUND

Cryptococcus neoformans is the third most common cause of invasive fungal infection in solid organ transplant (SOT) recipients. While cryptococcal infection can involve any organ, cases of myocarditis are exceedingly rare.

METHODS

A retrospective chart review was completed for this case report.

RESULTS

We present the case of a 21-year-old heart transplant recipient who developed disseminated cryptococcal infection with biopsy-proven cryptococcal myocarditis.

CONCLUSIONS

Cryptococcal disease in SOT recipients poses diagnostic and therapeutic challenges. There are no current guidelines for the duration of cryptococcal myocarditis treatment. Repeat myocardial biopsy may play a role in guiding length of therapy.

Outcomes of transplant recipients with pretransplant Nocardia colonization or infection

BACKGROUND

Specific pretransplant infections have been associated with poor posttransplant outcomes. However, the impact of pretransplant Nocardia isolation has not been studied.

METHODS

We performed a retrospective study from three centers in Arizona, Florida, and Minnesota of patients with Nocardia infection or colonization who subsequently underwent solid organ or hematopoietic stem cell transplantation from November 2011 through April 2022. Outcomes included posttransplant Nocardia infection and mortality.

RESULTS

Nine patients with pretransplant Nocardia were included. Two patients were deemed colonized with Nocardia, and the remaining seven had nocardiosis. These patients underwent bilateral lung (N = 5), heart (N = 1), heart-kidney (N = 1), liver-kidney (N = 1), and allogeneic stem cell transplantation (N = 1) at a median of 283 (interquartile range [IQR] 152-283) days after Nocardia isolation. Two (22.2%) patients had disseminated infection, and two were receiving active Nocardia treatment at the time of transplantation. One Nocardia isolate was resistant to trimethoprim-sulfamethoxazole (TMP-SMX) and all patients received TMP-SMX prophylaxis posttransplant, often for extended durations. No patients developed posttransplant nocardiosis during a median follow-up of 1.96 (IQR 0.90-6.33) years. Two patients died during follow-up, both without evidence of nocardiosis.

CONCLUSIONS

This study did not identify any episodes of posttransplant nocardiosis among nine patients with pretransplant Nocardia isolation. As patients with the most severe infections may have been denied transplantation, further studies with larger sample sizes are needed to better analyze any impact of pretransplant Nocardia on posttransplant outcomes. However, among patients who receive posttransplant TMP-SMX prophylaxis, these data suggest pretransplant Nocardia isolation may not impart a heightened risk of posttransplant nocardiosis.

Invasive fungal infections in liver diseases

Patients with liver diseases, including decompensated cirrhosis, alcohol-associated hepatitis, and liver transplant recipients are at increased risk of acquiring invasive fungal infections (IFIs). These infections carry high morbidity and mortality. Multiple factors, including host immune dysfunction, barrier failures, malnutrition, and microbiome alterations, increase the risk of developing IFI. Candida remains the most common fungal pathogen causing IFI. However, other pathogens, including Aspergillus, Cryptococcus, Pneumocystis, and endemic mycoses, are being increasingly recognized. The diagnosis of IFIs can be ascertained by the direct observation or isolation of the pathogen (culture, histopathology, and cytopathology) or by detecting antigens, antibodies, or nucleic acid. Here, we provide an update on the epidemiology, pathogenesis, diagnosis, and management of IFI in patients with liver disease and liver transplantation.

Donor-Derived Infection's Prevention and Control in Kidney Transplantation

BACKGROUND

The study aimed to summarize the experience of donor selection and recipient therapy in the face of potential donor-derived infections and improve the quality of donor organ utilization, which would help reduce the risk of infection after recipient operation and decrease the risk of loss or even death of recipient kidney transplantation.

METHODS

In this study, 132 kidneys from 70 donors and their recipients who underwent surgery between July 2017 and January 2021 were studied to perform a retrospective analysis of their etiologic examination results and treatment process.

RESULTS

In the 70 donors, only 25 had negative etiologic examination results, accounting for 35.71%. Among the 132 recipients, 31.82% had positive culture results, 3 (2.27%) experienced donor-derived infections, and one died.

CONCLUSIONS

Although infection in the donor before the donation is quite common, the incidence of donor-derived infections is relatively low. The targeted and preventive application of adequate sensitive antibiotics in the whole course of therapy was the cornerstone for treating recipients at potential risk of potential donor-derived infection. The changes in infection indicators in the recipient should be closely monitored, which would guide medication adjustments timely. These measures could, to a great degree, ensure the prognosis of the recipient, in turn reducing the adverse events caused by donor-derived infections.

Donor heart selection: Evidence-based guidelines for providers

The proposed donor heart selection guidelines provide evidence-based and expert-consensus recommendations for the selection of donor hearts following brain death. These recommendations were compiled by an international panel of experts based on an extensive literature review.

Donor-derived Cryptococcus gattii sensu stricto infection in two kidney transplant recipients, southeastern United States

Cryptococcus gattii infection is a rare cause of severe pulmonary disease and meningoencephalitis that has only recently been detected in the southeastern United States. We describe an organ transplant-associated outbreak of C. gattii infection involving an HIV-negative immunosuppressed donor in this region who died following new-onset headache and seizure of unknown cause. Retrospective cryptococcal antigen (CrAg) testing of donor serum was positive. Two of the three transplant recipients developed severe C. gattii infection 11 and 12 weeks following transplantation. One recipient died from severe pulmonary infection, identified on autopsy, and the other ill recipient survived following treatment for cryptococcal meningitis. This outbreak underscores the importance of considering cryptococcosis in patients with clinical findings suggestive of subacute meningitis or other central nervous system (CNS) pathology, and the potential benefit of routine pre-transplant donor CrAg screening using lateral flow assay to guide recipient antifungal prophylaxis. The case also adds to emerging evidence that C. gattii is a potential threat in the southeastern United States.

Cryptococcus transmission through solid organ transplantation in the United States: A report from the Ad Hoc Disease Transmission Advisory Committee

Cryptococcus species can cause serious life-threatening infection in solid organ transplant recipients by reactivation of prior infection, posttransplant de novo infection, or donor transmission from the transplanted organ. Although previously reported in the literature, the extent of donor-derived cryptococcosis in the United States has not been documented. We analyzed potential donor-derived Cryptococcus transmission events reported to the Organ Procurement and Transplantation Network (OPTN) for investigation by the Ad Hoc Disease Transmission Advisory Committee (DTAC). All reports between 2009 and 2019 in which transmission to recipients was designated proven or probable, or determined to be averted due to implementation of prophylaxis (intervention without disease transmission-"IWDT") were included. During 2009-2019, 58 reports of potential donor-derived cryptococcosis were submitted to DTAC. Among these reports, 12 donors were determined to have resulted in proven or probable transmission to 23/34 (67.6%) recipients. Most of these donors (10/12 [83%]) exhibited central nervous system-related symptoms prior to death and 5/23 (22%) infected recipients died. For 11 different donors, prophylaxis, most often with fluconazole, was administered to 23/35 (65.7%) recipients. Clinicians should maintain awareness of donor-derived cryptococcosis and consider prompt prophylaxis or treatment followed by reporting to OPTN for further investigation.

Update on Respiratory Fungal Infections in Cystic Fibrosis Lung Disease and after Lung Transplantation

Cystic fibrosis is the most common autosomal-recessive metabolic disease in the Western world. Impaired trans-membrane chloride transport via the cystic fibrosis transmembrane conductance regulator (CFTR) protein causes thickened body fluids. In the respiratory system, this leads to chronic suppurative cough and recurrent pulmonary infective exacerbations, resulting in progressive lung damage and respiratory failure. Whilst the impact of bacterial infections on CF lung disease has long been recognized, our understanding of pulmonary mycosis is less clear. The range and detection rates of fungal taxa isolated from CF airway samples are expanding, however, in the absence of consensus criteria and univocal treatment protocols for most respiratory fungal conditions, interpretation of laboratory reports and the decision to treat remain challenging. In this review, we give an overview on fungal airway infections in CF and CF-lung transplant recipients and focus on the most common fungal taxa detected in CF, Aspergillus fumigatus, Candida spp., Scedosporium apiospermum complex, Lomentospora species, and Exophiala dermatitidis, their clinical presentations, common treatments and prophylactic strategies, and clinical challenges from a physician’s point of view.

Early Cardiopulmonary Cryptococcus neoformans Infection After Liver Transplant: A Case Report

Cryptococcal infection (CI) is an uncommon fungal disease that poses a particular fatal risk to liver transplant (LT) recipients because of the potential rapid development and dissemination of the disease. Depending on the pathophysiology, CI may manifest with a wide range of clinical presentations that may delay early diagnosis and timely treatment. Additionally, most anticryptococcal therapies may threaten LT recipients owing to the associated hepatotoxicity of these medications. We report a case of a 25-year-old woman who received an LT for cryptogenic cirrhosis and developed rapidly progressive CI with pulmonary, myocardial, and cerebral involvement within a month of transplantation. She presented with severe pulmonary hypertension refractory to medical management and subsequently died despite our efforts. Herein, we review the etiology of cryptococcosis, the natural history of cryptococcal disease, and standard treatments for CI, and we highlight peculiarities of Cryptococcus neoformans infection in solid organ transplant recipients.

Cryptococcal pericarditis in a heart transplant recipient

We present a case of Cryptococcus neoformans pericarditis in a cardiac transplant recipient. This article reviews the diagnosis, treatment, and complications of cryptococcosis specifically in transplant patients. While pericarditis is a rare manifestation of Cryptococcus infection, this case highlights that cryptococcosis should be considered in the differential diagnosis for solid organ transplant and immunocompromised patients presenting with pericardial effusions.

Transmission of cryptococcosis by liver transplantation: A case report and review of literature

BACKGROUND

Cryptococcosis is a fungal infection caused by the yeast-like encapsulated basidiomycetous fungus of the Cryptococcus neoformans (C. neoformans) species complex. These fungi are ubiquitous in soil and bird droppings, and infection by them is an important global health concern, particularly in immunosuppressed patients, such as organ transplant recipients and those infected by the human immunodeficiency virus. The fungus usually enters the body through the respiratory tract, but extremely rare cases of infection acquired by transplantation of solid organs have been reported.

CASE SUMMARY

We report a case of disseminated cryptococcosis in a liver transplant recipient, diagnosed 2 wk after the procedure. The patient initially presented with fever, hyponatremia and elevated transaminase levels, manifesting intense headache after a few days. Blood cultures were positive for C. neoformans. Liver biopsy showed numerous fungal elements surrounded by gelatinous matrix and sparse granulomatous formations. Magnetic resonance imaging of the brain showed multiple small lesions with low signal in T2, peripheric enhancement and edematous halo, diffuse through the parenchyma but more concentrated in the subcortical regions. Treatment with amphotericin B for 3 wk, followed by maintenance therapy with fluconazole, led to complete resolution of the symptoms. The recipients of both kidneys from the same donor also developed disseminated cryptococcosis, confirming the transplant as the source of infection. The organ donor lived in a rural area, surrounded by tropical rainforest, and had negative blood cultures prior to organ procurement.

CONCLUSION

This case highlights the risk of transmission of fungal diseases, specifically of C. neoformans, through liver graft during liver transplantation.

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.

Very early-onset of Cryptococcus neoformans disease following liver transplantation: Report of two cases and a review of the literature

Cryptococcosis is the third most common invasive fungal infection following solid organ transplantation, and mortality is high. Most cases occur late and are due to reactivation of latent infection; however, very early reactivation and donor-derived transmission can occur. Routine screening pre-transplant and antifungal prophylaxis for cryptococcosis post-transplant in solid organ transplantation are not standard practice. We present two cases of very early-onset Cryptococcus neoformans disease following liver transplantation to highlight the need to consider individualized pre-transplant screening and be aware that reactivation of Cryptococcosis neoformans can occur in the immediate post-transplant period.

Central Nervous System Cryptococcal Infections in Non-HIV Infected Patients

Central nervous system (CNS) cryptococcosis in non-HIV infected patients affects solid organ transplant (SOT) recipients, patients with malignancy, rheumatic disorders, other immunosuppressive conditions and immunocompetent hosts. More recently described risks include the use of newer biologicals and recreational intravenous drug use. Disease is caused by Cryptococcus neoformans and Cryptococcus gattii species complex; C. gattii is endemic in several geographic regions and has caused outbreaks in North America. Major virulence determinants are the polysaccharide capsule, melanin and several ‘invasins’. Cryptococcal plb1, laccase and urease are essential for dissemination from lung to CNS and crossing the blood–brain barrier. Meningo-encephalitis is common but intracerebral infection or hydrocephalus also occur, and are relatively frequent in C. gattii infection. Complications include neurologic deficits, raised intracranial pressure (ICP) and disseminated disease. Diagnosis relies on culture, phenotypic identification methods, and cryptococcal antigen detection. Molecular methods can assist. Preferred induction antifungal therapy is a lipid amphotericin B formulation (amphotericin B deoxycholate may be used in non-transplant patients) plus 5-flucytosine for 2–6 weeks depending on host type followed by consolidation/maintenance therapy with fluconazole for 12 months or longer. Control of raised ICP is essential. Clinicians should be vigilant for immune reconstitution inflammatory syndrome.

Cryptococcosis in solid organ transplantation-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 cryptococcosis in the pre- and post-transplant period. The current update now includes a discussion of cryptococcosis, which is the third most common invasive fungal infection in SOT recipients. Infection often occurs a year after transplantation; however, early infections occur and donor-derived infections have been described within 3 months after transplant. There are two main species that cause infection, Cryptococcus neoformans and C gattii. Clinical onset may be insidious, but headaches, fevers, and mental status changes should warrant diagnostic testing. The lateral flow cryptococcal antigen assay is now the preferred test from serum and cerebrospinal fluid due to its rapidity, accuracy, and cost. A lumbar puncture with measurement of opening pressure is recommended for patients with suspected or proven cryptococcosis. Lipid amphotericin B plus 5-flucytosine is used as initial treatment of meningitis, disseminated infection, and moderate-to-severe pulmonary infection, followed by fluconazole as consolidation therapy. Fluconazole is effective for mild-to-moderate pulmonary infection. Immunosuppression reduction as part of management may lead to immune reconstitution syndrome that may resemble active disease.

Disseminated Cryptococcosis After Liver Transplant: A Case Report

Cryptococcosis is an opportunistic infection caused by the Basidiomycota Cryptococcus neoformans (Cryptococcus gattii), which affects immunosuppressed patients and less frequently immunocompetent patients. Solid-organ transplant recipients are a particularly high-risk group, depending on the net state of immunosuppression. In these patients, the infection usually appears after the first year after transplant, although it may occur earlier in liver transplant recipients. In most cases, the infection is secondary to the reactivation of a latent infection, although it may be due to an unidentified pretransplant infection by primary infection. Less frequently, it may be transmitted by the graft. The lung and central nervous system are most frequently involved. Extrapulmonary involvement is seen in 75% of the cases, and disseminated disease occurs in 61%, with mortality ranging from 17% to 50% when the central nervous system is involved. Here, we report a case of disseminated cryptococcosis (lymphadenitis, meningitis, pulmonary nodules, and possibly sacroiliitis) in a patient after liver transplant, with good clinical and microbiological outcomes and without relapse.

Drug development for cryptococcosis treatment: what can patents tell us?

BACKGROUND

Cryptococcosis is one of the most devastating fungal infections in humans. Despite the disease's clinical importance, current therapy is based on limited antifungals that are either toxic, inefficient, unavailable worldwide, or that quickly lead to resistance.

OBJECTIVES

The goal of this study was to provide insight into the future of cryptococcosis treatment by describing the patent scenario in this field.

METHODS

We identified and analysed patent documents revealing compounds with anti-cryptococcal activity supported by experimental evidence.

FINDINGS

Patenting in this field has been historically low, with an overall tendency of increase since 2012. Most applications are single filings, suggesting that they do not encompass strategic inventions requiring broad protection. Research and development essentially took place in China and the United States, which also represent the main countries of protection. Both academic and corporate institutions contributed to patenting in this field. Universities are the leading actors, with the highest patent family counts.

CONCLUSION

The low number of patents in this field indicates that efforts to mitigate the unmet needs for cryptococcosis treatment remain insufficient. Without investment to drive research and innovation, patients will likely continue to face inadequate assistance. Given the current scenario characterised by poor funding and low interest for technological development, drug repurposing may be the best alternative for cryptococcosis treatment.

Prevention and Treatment of Yeast and Endemic Fungal Infections

Invasive fungal infections (IFIs) remain an important complication of solid organ transplantation owing to their significant morbidity and mortality and include infections due to Candida, Cryptococcus, endemic mycosis, and other rare yeasts and molds. IFIs occur in different intervals posttransplantation and depend on a number of extrinsic and intrinsic risk factors, some of which are specific to the type of organs transplanted, surgical techniques, and type of immunosuppressive medications. Donor-derived IFIs and emergence of new multidrug-resistant yeasts have been reported in various healthcare settings. Clinical manifestations of yeast and endemic fungal infections vary in different types of organ transplants. Diagnosis of IFIs in SOT recipients is challenging due to their nonspecific signs and symptoms owing to the impaired inflammatory responses as a result of immunosuppression and the lack of highly sensitive and specific diagnostic modalities. Early diagnosis is key to successful therapy, and physicians should have a high index of suspicion based on risk factors and epidemiology of these pathogens. Antifungal treatment strategies for yeast infections have been outlined in various society guidelines. Management of complications that arise before or during antifungal therapy is critical for optimizing clinical response.

Yeast Infections in Solid Organ Transplantation

Invasive candidiasis (IC) remains the most common invasive fungal infection following solid-organ transplant (SOT), but risk factors are evolving. Current challenges include infection due to drug resistant non-albicans and emerging novel species such as Candida auris. Preventive antifungal use in SOT needs to be re-examined in light of these current challenges. Cryptococcosis is the second most common IFI following SOT. Cryptococcus gattii is an emerging pathogen that can have reduced in-vitro susceptibility to antifungal agents. Cryptococcus associated IRIS in SOT is a clinical entity that warrants heightened awareness for timely recognition and management.

Solving the mystery: Hyalinized cyst wall containing organism-like structures in a lung transplant donor

A 59-year-old man with non-ischemic cardiomyopathy underwent orthotopic heart transplantation. The donor, a 31-year-old male declared brain dead after a gunshot wound to the head, was considered high risk due to history of incarceration, illicit drug use, and sex with a HIV-positive partner. At organ procurement, the heart, kidneys, pancreas, and liver looked grossly normal. A small right lower lobe nodule was noticed, and lung biopsy was performed. Bronchoscopy showed purulent secretions in the right lower lobe. Images from pathology are presented. Lung biopsy confirmed the presence of hyalinized cyst wall containing organism-like structures. A combination of culture, microscopic morphology, and gene sequencing was used to identify the causative organism. The patient and all other organ recipients received appropriate antifungal prophylaxis and remain asymptomatic 6 months post-transplant.

Cryptococcoma of a transplanted kidney in a patient presenting with recurrent urinary tract infection: a case report

BACKGROUND

Cryptococcosis is an important opportunistic infection of organ transplant recipients. It is the third most common fungal infection of transplant patients and occurs especially in kidney recipients. Cryptococcus neoformans is a ubiquitous fungus which infects humans by inhalation of spores. C. gattii has more recently been recognised as a pathogen. Infection commonly is disseminated affecting mainly the central nervous system and the lungs. Cryptococcoma, a localised form of the disease, has been described in various organs. We present a unique case of a cryptococcoma in a transplanted kidney. The lesion was not seen on ultrasound or uncontrasted computerised tomography but was detected by FDG-PET/CT.

CASE PRESENTATION

A 30 year old woman received a deceased donor kidney transplant in 2005. Due to chronic allograft nephropathy in 2014, cyclosporine and azathioprine immunosuppression was changed to tacrolimus and mycophenolate. After rapid deterioration of renal function in 2015 due to suspected non-adherence to immunosuppressants, steroid pulses were administered. The patient developed severe recurrent bacterial urinary tract infections and demonstrated several features of severe immunosuppression. She was treated for cytomegalovirus infection and BK virus was demonstrated in the urine. In addition, Kaposi sarcoma of the stomach was diagnosed on endoscopic biopsy. A metabolically-active lesion of the kidney transplant was imaged on FDG-PET/CT scan. Biopsy of the lesion demonstrated infection with cryptococcus. Escherichia coli with the same antibiotic sensitivity spectrum as that in the urine was cultured from the biopsy. Cryptococcus was not cultured from urine at that time or from several subsequent specimens. The lesion was not detected by conventional imaging. The patient manifested no other evidence of cryptococcosis. The lesion responded poorly to treatment with fluconazole.

CONCLUSIONS

This is probably the first report of a case of a cryptococcoma in a transplanted organ. FDG-PET/CT scan, which is dependent on cellular metabolism, proved useful in visualising the lesion. Clinicians should be aware of this rare presentation of cryptococcosis in organ transplant recipients.

Cryptococcal disease in the solid organ transplant setting: review of clinical aspects with a discussion of asymptomatic cryptococcal antigenemia

PURPOSE OF REVIEW

Cryptococcal infections are an important cause of morbidity and mortality in solid organ transplant patients. Here, we review the microbiology, epidemiology, clinical course, treatment, and outcomes of Cryptococcus in solid organ transplant recipients.

RECENT FINDINGS

We identify the unique findings in solid organ transplant patients when compared to other immunocompromised patients such as those with HIV. We also describe our experience and outcomes with regard to solid organ transplant patients who do not have positive fungal cultures, but cryptococcal antigen positivity and concern for cryptococcal disease.

SUMMARY

Our review will highlight the importance of these new diagnostic techniques in those with Cryptococcus and solid organ transplant, which will be the subject of new research.

Cryptococcosis today: It is not all about HIV infection

Purpose of the review

Cryptococcal disease is most often thought of in the context of HIV infection. Much of our knowledge of the disease originates from its management in the HIV-positive population over the last 30 years. While the majority of cases globally continue to occur in the setting of advanced HIV, Cryptococcus species is increasingly responsible for disease in HIV-negative populations including those considered normal hosts and these HIV-negative populations will be the focus of this review.

Recent findings

Currently available data indicated that significant differences exist in epidemiology, clinical presentation, management and outcomes of cryptococcal disease in HIV-negative populations when compared to those living with HIV.

Summary

Further research is required to improve our knowledge of cryptococcal disease in particular in HIV-negative cohorts so as to optimise management of the disease in the future.

Epidemiology of Cryptococcosis and Cryptococcal Meningitis in a Large Retrospective Cohort of Patients After Solid Organ Transplantation

BACKGROUND

Cryptococcosis is the third most common invasive fungal infection in solid organ transplant (SOT) recipients. There are no nationally representative data describing the incidence, risk factors, and outcomes of cryptococcosis after SOT.

METHODS

We assembled a large cohort of adult SOT recipients using Classification of Diseases, Ninth Revision, Clinical Modification billing data from Healthcare Cost and Utilization Project State Inpatient Databases of Florida (2006-2012), New York (2006-2011), and California (2004-2010). Demographics, comorbidities, death, and cryptococcal infections coded during hospitalization were identified.

RESULTS

A total of 42634 adults with SOT were identified during the study period. Cryptococcal disease was identified in 0.37% (n = 158), 44% of which had meningitis (n = 69). Median time to diagnosis of cryptococcosis was 464 days (range, 4-2393). The median time to onset of cryptococcosis was earlier for lung (191 days; range, 7.5-1816), heart (195 days; range, 4-1061), and liver (200 days; range, 4-1581) compared with kidney transplant recipients (616 days; range, 12-2393; P < .001, log rank test). Very early-onset disease (<30 days after transplantation) more frequently occurred in liver and lung transplant recipients. Lung transplant recipients had the highest risk of cryptococcosis (hazard ratio [HR], 2.10; 95% confidence interval [CI], 1.21-3.60). Cryptococcosis was associated with death (HR, 2.29; 95% CI, 1.68-3.11), after adjusting for age, type of SOT, and other comorbidities.

CONCLUSIONS

Cryptococcosis is rare after SOT, but it is associated with significantly increased risk of death. Lung transplant recipients are at highest risk for cryptococcosis among SOTs. Nonkidney transplants have earlier onset of cryptococcosis and higher risk of death compared with kidney transplant recipients.

Cryptococcosis

Cryptococcosis is an invasive mycosis caused by pathogenic encapsulated yeasts in the genus Cryptococcus. Cryptococcus gained prominence as a pathogen capable of widespread disease outbreaks in vulnerable populations. We have gained insight into the pathobiology of Cryptococcus, including the yeast' s capacity to adapt to environmental pressures, exploit new geographic environments, and cause disease in both immunocompromised and apparently immunocompetent hosts. Inexpensive, point-of-care testing makes diagnosis more feasible than ever. The associated worldwide burden and mortality remains unacceptably high. Novel screening strategies and preemptive therapy offer promise at making a sustained and much needed impact on this sugar-coated opportunistic mycosis.

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.

Colliding Epidemics and the Rise of Cryptococcosis

Discovered more than 100 years ago as a human pathogen, the Cryptococcus neoformans–Cryptococcus gattii (C. neoformans–C. gattii) complex has seen a large global resurgence in its association with clinical disease in the last 30 years. First isolated in fermenting peach juice, and identified as a human pathogen in 1894 in a patient with bone lesions, this environmental pathogen has now found niches in soil, trees, birds, and domestic pets. Cryptococcosis is well recognized as an opportunistic infection and was first noted to be associated with reticuloendothelial cancers in the 1950s. Since then, advances in transplant immunology, medical science and surgical techniques have led to increasing numbers of solid organ transplantations (SOT) and hematological stem cell transplantations being performed, and the use of biological immunotherapeutics in increasingly high-risk and older individuals, have contributed to the further rise in cryptococcosis. Globally, however, the major driver for revivification of cryptococcosis is undoubtedly the HIV epidemic, particularly in Sub-Saharan Africa where access to care and antiretroviral therapy remains limited and advanced immunodeficiency, poverty and malnutrition remains the norm. As a zoonotic disease, environmental outbreaks of both human and animal cryptococcosis have been reported, possibly driven by climate change. This is best exemplified by the resurgence of C. gattii infection in Vancouver Island, Canada, and the Pacific Northwest of the United States since 1999. Here we describe how the colliding epidemics of HIV, transplantation and immunologics, climate change and migration have contributed to the rise of cryptococcosis.

Cryptococcus: Shedding New Light on an Inveterate Yeast

Cryptococcus has emerged as a significant pathogen in immunocompromised patients. While the diagnostic testing and the antifungal treatment of cryptococcal infections have become firmly established in clinical practice, new developments and areas of ambiguity merit further consideration. These include the potential for donor transmission of Cryptococcus; cirrhosis-associated cryptococcosis, particularly during transplant candidacy; the utility of serum cryptococcal antigen testing of asymptomatic individuals in high-prevalence, poor-resource areas; pathogenesis and treatment of the immune reconstitution syndrome, specifically in relation to antiretroviral therapy and immunosuppressive medications; and new challenges posed by the emerging species of Cryptococcus gatti. In this article, we summarize the literature pertaining to these topics, focusing on recent progress.

Targeted versus universal antifungal prophylaxis among liver transplant recipients

Guidelines recommend targeted antifungal prophylaxis for liver transplant (LT) recipients based on tiers of risk, rather than universal prophylaxis. The feasibility and efficacy of tiered, targeted prophylaxis is not well established. We performed a retrospective study of LT recipients who received targeted prophylaxis (n = 145; voriconazole [VORI; 54%], fluconazole [8%], no antifungal [38%]) versus universal VORI prophylaxis (n = 237). Median durations of targeted and universal prophylaxis were 11 and 6 days, respectively (p < 0.0001). The incidence of invasive fungal infections (IFIs) in targeted and universal groups was 6.9% and 4.2% (p = 0.34). Overall, intra-abdominal candidiasis (73%) was the most common IFI. Posttransplant bile leaks (p = 0.001) and living donor transplants (p = 0.04) were independent risk factors for IFI. IFIs occurred in 6% of high-risk transplants who received prophylaxis and 4% of low-risk transplants who did not receive prophylaxis (p = 1.0). Mortality rates (100 days) were 10% (targeted) and 7% (universal) (p = 0.26); attributable mortality due to IFI was 10%. Compliance with prophylaxis recommendations was 97%. Prophylaxis was discontinued for toxicity in 2% of patients. Targeted antifungal prophylaxis in LT recipients was feasible and safe, effectively prevented IFIs and reduced the number of patients exposed to antifungals. Bile leaks and living donor transplants should be considered high-risk indications for prophylaxis.

Cryptococcal meningitis: epidemiology and therapeutic options

Cryptococcal meningitis causes morbidity and mortality worldwide. The burden of disease is greatest in middle- and low-income countries with a high incidence of human immunodeficiency virus (HIV) infection. Patients taking immunosuppressive drugs and some immunocompetent hosts are also at risk. Treatment of cryptococcal meningitis consists of three phases: induction, consolidation, and maintenance. Effective induction therapy requires potent fungicidal drugs (amphotericin B and flucytosine), which are often unavailable in low-resource, high-endemicity settings. As a consequence, mortality is unacceptably high. Wider access to effective treatment is urgently required to improve outcomes. For human immunodeficiency virus-infected patients, judicious management of asymptomatic cryptococcal antigenemia and appropriately timed introduction of antiretroviral therapy are important.

Radioimmunotherapy of Cryptococcus neoformans spares bystander mammalian cells

AIM

Previously, we showed that radioimmunotherapy (RIT) for cryptococcal infections using radioactively labeled antibodies recognizing the cryptococcal capsule reduced fungal burden and prolonged survival of mice infected with Cryptococcus neoformans. Here, we investigate the effects of RIT on bystander mammalian cells.

MATERIALS & METHODS

Heat-killed C. neoformans bound to anticapsular antibodies, unlabeled or labeled with the β-emitter rhenium-188 (16.9-h half-life) or the α-emitter bismuth-213 (46-min half-life), was incubated with macrophage-like J774.16 cells or epithelial-like Chinese hamster ovary cells. Lactate dehydrogenase activity, crystal violet uptake, reduction of tetrazolium dye (2,3)-bis-(2-methoxy-4-nitro-5-sulfenyl)-(2H)-terazolium-5-carboxanilide and nitric oxide production were measured.

RESULTS

The J774.16 and Chinese hamster ovary cells maintained membrane integrity, viability and metabolic activity following exposure to radiolabeled C. neoformans.

CONCLUSION

RIT of C. neoformans is a selective therapy with minimal effects on host cells and these results are consistent with observations that RIT-treated mice with cryptococcal infection lacked RIT-related pathological changes in lungs and brain tissues.

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.

Cryptococcal infection in non-HIV immunosuppressed patients - Three case reports in a nephrology setting

Cryptococcal infection has been increasing among immunosuppressed population. We report three cases of Cryptococcus neoformans infection in immunosuppressed patients – two renal transplanted and one with lupus nephritis. Early infection (<3months) was diagnosed in two – an allograft Cryptococcus infection and a central nervous system involvement. The third, a 10-year transplant vintage patient, presented with cryptococcal meningitis. Amphotericin B provided good clinical outcomes. We outline the importance of suspicion for cryptococcal infection in immunosuppressed patients.

Donor-derived Cryptococcus infection in liver transplant: case report and literature review

Cryptococcosis occurring within 30 days after transplant is unusual. We present a case of cryptococcosis diagnosed within 2 weeks of liver transplant and cryptococcal infection transmitted by liver transplant is considered as the cause. A 63-year-old woman with hepatitis C virus-related cirrhosis and hepatocellular carcinoma had an orthotopic liver transplant from a 45-year-old donor. The immediate postoperative course was smooth, although she was confused with a fever, tachycardia, respiratory failure of 1 week's duration after the orthotopic liver transplant. A liver biopsy was performed for hyperbilirubinemia 2 weeks after the orthotopic liver transplant that showed a Cryptococcus-like yeast. Her blood culture was reexamined, and it was confirmed as Cryptococcus neoformans that had been misinterpreted as candida initially. At the time of the re-examination, her sputum was clear. We checked her preoperative blood sample, retrospectively, for serum cryptococcal antigen with negative result. She was on liposomal amphotericin treatment for 1 month when her blood culture became negative. She was discharged home, with good liver function and a low antigen titer for cryptococcal infection. Cryptococcal disease usually develops at a mean of 5.6 months after transplant. However an early occurrence is rare. Apart from that, its variable clinical presentations make early detection difficult. It might be an early reactivation or a donor-derived infection. The latter usually occurs in unusual sites (eg, the transplanted organ as the sole site of involvement). Our case presented as cryptococcoma and liver involvement was diagnosed by an unintentional liver biopsy.

Update on donor-derived infections in liver transplantation

Advances in surgical techniques, immunosuppressive medications, and robust infectious disease prophylaxis have resulted in liver transplantation becoming the treatment of choice for patients with end-stage liver disease and unresectable hepatocellular carcinoma. Nonetheless, organ transplantation is not without risk. Unexpected donor-derived disease transmission is a newly recognized risk that complicates approximately 0.2% of all organ transplants. We review the epidemiology of donor-derived infectious diseases and methods of risk mitigation with a focus on liver transplantation.

Donor-derived fungal infections in organ transplant recipients: guidelines of the American Society of Transplantation, infectious diseases community of practice

Donor-derived fungal infections can be associated with serious complications in transplant recipients. Most cases of donor-derived candidiasis have occurred in kidney transplant recipients in whom contaminated preservation fluid is a commonly proposed source. Donors with cryptococcal disease, including those with unrecognized cryptococcal meningoencephalitis may transmit the infection with the allograft. Active histoplasmosis or undiagnosed and presumably asymptomatic infection in the donor that had not resolved by the time of death can result in donor-derived histoplasmosis in the recipient. Potential donors from an endemic area with either active or occult infection can also transmit coccidioidomycosis. Rare instances of aspergillosis and other mycoses, including agents of mucormycosis may also be transmitted from infected donors. Appropriate diagnostic evaluation and prompt initiation of appropriate antifungal therapy are warranted if donor-derived fungal infections are a consideration. This document discusses the characteristics, evaluation and approach to the management of donor-derived fungal infections in organ transplant recipients.