Invasive fungal infections and antifungal therapies in solid organ transplant recipients

Modulatory immune responses in fungal infection associated with organ transplant - advancements, management, and challenges

Organ transplantation stands as a pivotal achievement in modern medicine, offering hope to individuals with end-stage organ diseases. Advancements in immunology led to improved organ transplant survival through the development of immunosuppressants, but this heightened susceptibility to fungal infections with nonspecific symptoms in recipients. This review aims to establish an intricate balance between immune responses and fungal infections in organ transplant recipients. It explores the fundamental immune mechanisms, recent advances in immune response dynamics, and strategies for immune modulation, encompassing responses to fungal infections, immunomodulatory approaches, diagnostics, treatment challenges, and management. Early diagnosis of fungal infections in transplant patients is emphasized with the understanding that innate immune responses could potentially reduce immunosuppression and promise efficient and safe immuno-modulating treatments. Advances in fungal research and genetic influences on immune-fungal interactions are underscored, as well as the potential of single-cell technologies integrated with machine learning for biomarker discovery. This review provides a snapshot of the complex interplay between immune responses and fungal infections in organ transplantation and underscores key research directions.

Marijuana use and post-transplant complications and non-compliance in liver transplant patients

BACKGROUND

Liver transplant (LT) is a lifesaving treatment for patients with end stage liver disease. Historically, institutions across the United States have deemed active marijuana use as an exclusion criterion for listing. This study aims to investigate LT outcomes in patients with history of marijuana use prior to LT.

METHODS

We performed a retrospective review of 111 patients who tested positive for marijuana on urine drug screen during initial LT evaluation between February 2016 and January 2021. 100 non-marijuana users who underwent LT were cross matched for control. Patient demographics, substance use history, and transplant decisions were recorded. Post-LT variables were also collected up to 1 year post surgery including postoperative infections, issues with non-compliance, and continued substance use. Chi-square analysis was used to assess the association between pre-transplant marijuana use and post-transplant complications. Logistics regression was implemented to measure associations amongst the entire cohort.

RESULTS

From 111 marijuana users, 32 (29%) received a transplant. There was no statistical difference in post-LT outcomes between marijuana and non-marijuana users, including incidence of cardiac, respiratory, renal, psychiatric, or neurological complications, as well as readmission rates post-surgery. There were no statistically significant associations between marijuana use with post-transplant bacterial or fungal infections, medication non-compliance, or continued substance use (all p>0.05). Marijuana use was associated with pre-LT tobacco use (p = 0.020).

CONCLUSIONS

Our data indicates that marijuana is not associated with increased risk of postoperative noncompliance, other organ complications, infections, or death. As a single factor, marijuana may not need to be a contraindication for LT.

Primary spinal infections in patients with solid organ transplant: a systematic literature review and illustrative case

BACKGROUND

Primary spinal infections (PSIs) are a group of uncommon but serious infectious diseases considered more prevalent and aggressive among patients with chronic immunocompromised states. Association of PSI and solid organ transplant has not been systematically analyzed. The authors performed a systematic review analyzing clinical presentation and mortality of patients with PSI in the setting of solid organ transplant.

OBSERVATIONS

PSIs in patients with immunosuppressive therapy, such as those with solid organ transplant, may behave differently in terms of epidemiology, clinical presentation, and outcomes compared with nonimmunosuppressed patients. Overall PSI in solid organ transplant patients is associated with a high rate of neurological compromise, postoperative complications, and mortality.

LESSONS

Accurate diagnosis and appropriate treatment of PSI require a multidisciplinary effort. Localized pain is the most frequently reported symptom associated with PSI. As opposed to PSI in patients without transplant, inflammatory and infectious markers such as white blood cells and C-reactive protein are often not elevated. Furthermore, the causative microorganism profile varies significantly when compared to pyogenic spinal infection in patients without transplant. Aspergillus species was responsible for spondylodiscitis in transplant patients in more than 50% of cases, and the incidence of Aspergillus infection is projected to rise in the coming years.

Perioperative anidulafungin combined with triazole prophylaxis for the prevention of early invasive candidiasis in lung transplant recipients

BACKGROUND

Invasive candidiasis (IC) is a substantial cause of morbidity and mortality among lung transplant recipients (LTRs). Postoperative factors include prolonged hospital stay, central lines, delayed chest closure, and dehiscence increase IC risk. Correspondingly, current guidelines propose targeted IC coverage early posttransplant with fluconazole or an echinocandin.

METHODS

This retrospective analysis was performed on LTRs from January 2016 to January 2020 and evaluated effectiveness of a recent protocol utilizing perioperative anidulafungin for early IC prevention in addition to long-term triazole antifungal prophylaxis. Prior to this protocol, patients were primarily established on itraconazole prophylaxis alone. The primary endpoint was proven or probable IC within 90 days after transplant. Multivariable logistic regression modeling was used to assess risk factors for invasive fungal infection (IFI).

RESULTS

Among 144 LTRs, there was a numerically lower incidence of IC in the protocol group, although not statistically significant (6% vs. 13%, p = 0.16). Incidence of proven or probable IFI was 7.5% in the protocol cohort and 19.5% in the pre-protocol cohort (p = 0.038). In multivariable analysis, when controlling for lung allocation score (OR 1.04, 95% CI 1.01-1.08), donor perioperative culture with fungal growth (OR 2.92, 95% CI 1.02-8.92), and dehiscence (OR 3.54, 95% CI 1.14-10.85), protocol cohort was not significantly associated with IFI (OR 0.41, 95% CI 0.12-1.23).

CONCLUSIONS

To our knowledge, this is the first study investigating combination triazole/echinocandin use in the early post-lung transplant period. These findings demonstrate that in-hospital anidulafungin offers unclear benefit for early IC prevention when used in combination with triazole prophylaxis.

Invasive Fungal Infection After Lung Transplantation: Epidemiology in the Setting of Antifungal Prophylaxis

BACKGROUND

Lung transplant recipients commonly develop invasive fungal infections (IFIs), but the most effective strategies to prevent IFIs following lung transplantation are not known.

METHODS

We prospectively collected clinical data on all patients who underwent lung transplantation at a tertiary care academic hospital from January 2007-October 2014. Standard antifungal prophylaxis consisted of aerosolized amphotericin B lipid complex during the transplant hospitalization. For the first 180 days after transplant, we analyzed prevalence rates and timing of IFIs, risk factors for IFIs, and data from IFIs that broke through prophylaxis.

RESULTS

In total, 156 of 815 lung transplant recipients developed IFIs (prevalence rate, 19.1 IFIs per 100 surgeries, 95% confidence interval [CI] 16.4-21.8%). The prevalence rate of invasive candidiasis (IC) was 11.4% (95% CI 9.2-13.6%), and the rate of non-Candida IFIs was 8.8% (95% CI 6.9-10.8%). First episodes of IC occurred a median of 31 days (interquartile range [IQR] 16-56 days) after transplant, while non-Candida IFIs occurred later, at a median of 86 days (IQR 40-121 days) after transplant. Of 169 IFI episodes, 121 (72%) occurred in the absence of recent antifungal prophylaxis; however, IC and non-Candida breakthrough IFIs were observed, most often representing failures of micafungin (n = 16) and aerosolized amphotericin B (n = 24) prophylaxis, respectively.

CONCLUSIONS

Lung transplant recipients at our hospital had high rates of IFIs, despite receiving prophylaxis with aerosolized amphotericin B lipid complex during the transplant hospitalization. These data suggest benefit in providing systemic antifungal prophylaxis targeting Candida for up to 90 days after transplant and extending mold-active prophylaxis for up to 180 days after surgery.

Use of echinocandin prophylaxis in solid organ transplantation

Invasive fungal infections (IFIs) are a major threat to patients undergoing solid organ transplantation (SOT). Owing to improvements in surgical techniques, immunosuppression therapy and antifungal prophylaxis, the incidence of IFIs has been decreasing in recent years. However, IFI-associated morbidity and mortality remain significant. Invasive candidiasis (IC) and aspergillosis (IA) are the main IFIs after SOT. Risk factors for IC and IA continue to evolve, and thus strategies for their prevention should be constantly updated and targeted to both individual patient risk factors and local epidemiology. In this review, we discuss the current epidemiology and risk factors for IFIs in SOT recipients in the context of actual approaches to antifungal prophylaxis, including experience with the use of echinocandins, after SOT.

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.

Donor-Derived Candida dubliniensis Resulting in Perigraft Abscesses in a Liver Transplant Recipient Proven by Whole Genome Sequencing: A Case Report

BACKGROUND

The transmission of fungi via transplant, although well-known, has not often been molecularly proven. We describe a case of donor-derived candidiasis verified by whole genome sequencing.

CASE DESCRIPTION

The multiorgan donor was a 42-year-old woman with subdural hemorrhage. Procurement of the thoracic organs was performed followed by the abdominal organs. Tissue from the left bronchus grew Candida dubliniensis. The liver recipient was a 63-year-old woman with cryptogenic liver cirrhosis. She was noted to have worsening leukocytosis on postoperative day (POD) 9. Computed tomography of the abdomen and pelvis showed multiple rim-enhancing collections around the graft. Percutaneous drainage was performed. Fluid cultures grew C dubliniensis. C dubliniensis isolated from the donor's left bronchus and the liver recipient's abscesses were verified to be related by whole genome sequencing. We postulate that C dubliniensis colonizing the donor's transected trachea could have contaminated the inferior vena cava when the former was left open after explant of the donor's lungs. A portion of the donor's contaminated inferior vena cava was transplanted along with the liver graft, resulting in the infected collections in the recipient.

CONCLUSIONS

Our case report highlights the importance of maintaining a sterile field during organ procurement, especially in a multiorgan donor whose organs are explanted in succession.

Lung transplantation for bronchiolitis obliterans syndrome after allogenic hematopoietic stem cell transplantation

Bronchiolitis obliterans syndrome (BOS) after hematopoietic stem cell transplantation (HSCT) is a major cause of morbidity and mortality with limited treatment options. Lung transplantation (LTX) has been rarely reported as a treatment option for selected HSCT recipients with this problem. In the present study, we reported six patients who underwent LTX due to BOS after HSCT (two females, four males) from January 2012 to December 2014 in our center. The median time from HSCT to diagnosis of BOS was 2.5 years (ranging from 1 to 5 years). At a median time of 4 years (ranging from 2 to 5 years) after diagnosis of BOS, four patients received bilateral sequential LTX, and two patients received single LTX. One of the recipients suffered from mild acute rejection after LTX, another suffered from primary lung graft dysfunction on post-operation day 2, and three experienced fungal infections. The median time for follow-up after LTX was 19.5 months (ranging from 12 to 39 months). At present, all patients are alive with good functional capacity and no relapse of BOS and hematologic malignancy conditions. Patients who received bilateral LTX have better pulmonary functions than patients who received single LTX.

Modified release itraconazole amorphous solid dispersion to treat Aspergillus fumigatus: importance of the animal model selection

Previously, modified release itraconazole in the form of a melt-extruded amorphous solid dispersion based on a pH dependent enteric polymer combined with hydrophilic additives (HME-ITZ), exhibited improved in vitro dissolution properties. These properties agreed with pharmacokinetic results in rats showing high and sustained itraconazole (ITZ) systemic levels. The objective of the present study was to better understand the best choice of rodent model for evaluating the pharmacokinetic and efficacy of this orally administered modified release ITZ dosage form against invasive Aspergillus fumigatus. A mouse model and a guinea pig model were investigated and compared to results previously published. In the mouse model, despite similar levels as previously reported values, plasma and lung levels were variable and fungal burden was not statistically different for placebo controls, HME-ITZ and Sporanox^® (ITZ oral solution). This study demonstrated that the mouse model is a poor choice for studying modified release ITZ dosage forms based on pH dependent enteric polymers due to low fluid volume available for dissolution and low intestinal pH. To the contrary, guinea pig was a suitable model to evaluate modified release ITZ dosage forms. Indeed, a significant decrease in lung fungal burden as a result of high and sustained ITZ tissue levels was measured. Sufficiently high intestinal pH and fluids available for dissolution likely facilitated the dissolution process. Despite high ITZ tissue level, the primary therapeutic agent voriconazole exhibited an even more pronounced decrease in fungal burden due to its reported higher clinical efficacy specifically against Aspergillus fumigatus.

Who gets a lung transplant? Assessing the psychosocial decision-making process for transplant listing

In the United States, there is a significant shortage of available donor organs. This requires transplant professionals to hold simultaneous, yet divergent roles as (1) advocates for patients who are in need of a lifesaving transplant, and (2) responsible stewards in the allocation of scarce donor organs. In order to balance these roles, most transplant teams utilize a committee based decision-making process to select suitable candidates for the transplant waiting list. These committees use medical and psychosocial criteria to guide their decision to list a patient. Transplant regulatory bodies have established medical standards for identifying appropriate medical candidates for transplantation. However, transplant regulatory bodies have not developed policies to standardize psychosocial criteria for listing patients. This affords transplant centers the autonomy to develop their own psychosocial criteria for determining which patients will be placed on the transplant waiting list. This lack of a standardized policy has resulted in inconsistent psychosocial practices amongst transplant centers nationwide. Since there has been no formal review of the inconsistency in psychosocial policy and practice, this paper seeks to explore the non-standardized psychosocial approach to organ transplant listing. The authors review factors that are relevant to the standardization of the psychosocial decision-making process, including shared decision-making, clinician judgment, bias in decision-making and moral distress in transplant staff. We conclude with a discussion about the impact of these issues on psychosocial practices in solid organ transplantation.

Primary deep cutaneous candidiasis caused by Candida duobushaemulonii in a 68-year-old man: the first case report and literature review

Superficial candida infections of the skin are common, but deep cutaneous candidiasis, including secondary dissemination to the skin from systemic candidiasis, candidaemia or primary invasion due to skin defects such as trauma, is rare. These patients are usually immunosuppressed, but immunocompetent hosts can be affected as well. Candida albicans is the most common pathogen. However, non-albicans Candida species can cause deep skin invasion in rare circumstances. We report a case of deep cutaneous candidiasis caused by Candida duobushaemulonii in a 68-year-old man. Deep tissue invasion was confirmed by skin histopathology examination. The pathogen was initially identified as C. haemulonii using the VITEK^® 2 system for microbial identification, but was later determined to be C. duobushaemulonii based on sequencing of the internal transcribed spacer region of ribosomal DNA and D1/D2 region of 26S rDNA. The patient was successfully treated with amphotericin B, followed by fluconazole and surgical intervention. To the best of our knowledge, this is the first case of deep cutaneous infection by C. duobushaemulonii.

Successful Management of an Infected Aortic Stent Graft in a Liver Transplanted Patient

We report on a 57-year-old female liver transplanted patient who underwent endovascular aneurysm repair because of an infrarenal abdominal aortic aneurysm. Two months later, she developed an infection, and positron emission tomography computed tomography detected a paraprosthetic abscess. Explantation of the endoprosthesis and aortic reconstruction with a Y-shaped silver graft was made. The patient was discharged on the 12th postoperative day and shows up regularly in our outpatients department in a good clinical condition. After meticulous research of the current literature, this is the first published case of the successful management of an infected endovascular aortic stent in a liver transplanted patient.

Risk of infectious diseases and cutaneous tumours in solid organ recipients: A meta-analysis of literature

AIM: To compare the risk of cutaneous infections and tumours in kidney transplant recipients with data recently published about this topic.

METHODS: In the present work, we evaluated the incidence of bacterial, fungal and viral cutaneous infectious diseases and the development of skin cancers in a cohort of 436 patients who underwent a renal transplantation. The median age at transplantation of our patients was 50 years and the median duration of the immunosuppression was of 7.2 years. Data obtained from our cohort were compared with those obtained by a systematic review of the literature of the last 20 years about the same topic.

RESULTS: Infectious diseases were the most frequent dermatological disorders that were diagnosed after transplantation, affecting about the 16.5% of patients. Herpes virus reactivation occurs in about the 35% of patients and is more common within 6 mo from transplantation, whereas when the immunosuppression is reduced, skin infections are mainly represented by Human Papilloma Virus infections and localized mycosis, such as pityriasis versicolor and superficial candidiasis. Bacterial infections were relatively rare and occur mainly in the first months after transplantation. The cumulative risk to develop skin cancer enhance significantly over the time, as consequence of long-term immunosuppressive regiments. Endogenous and exogenous risk factors, as well as the schedule of immunosuppression can play a role and justify the different incidence of skin cancer in the various series.

CONCLUSION: Skin infections and cancer, commonly diagnosed in transplanted patients, impact on survival and life-quality, justifying the realization of follow-up programs for the early diagnosis and treatment.

Diagnosis of deep cutaneous fungal infections: correlation between skin tissue culture and histopathology

BACKGROUND

Deep cutaneous fungal infections (DCFIs) are responsible for significant morbidity and mortality, particularly in immunocompromised patients. Although a direct correlation between histopathologic examination and culture is expected, discordant findings may be seen, presenting a unique diagnostic and therapeutic challenge.

OBJECTIVES

We sought to determine the correlation between skin tissue cultures and histopathologic examination in patients with DCFI.

METHODS

This is a 10-year retrospective review (2003-2012) of patients with a diagnosis of DCFI seen at a single tertiary care institution. Tissue cultures and histopathologic findings were reviewed.

RESULTS

In 8 of 33 cases, fungal elements were seen on routine histopathologic sections but skin cultures were negative. Three of 8 of the discordant cases had concurrent positive non-skin tissue cultures that correlated with the pathology interpretation, and 3 of 8 patients in the discordant group died of systemic fungal infection.

LIMITATIONS

This was a retrospective study design and a single tertiary care institution experience.

CONCLUSIONS

The histopathologic interpretation of skin tissue specimens is critical for rapid and accurate diagnosis of DCFI. Despite the identification of fungal organisms on histopathologic assessment of skin tissue specimens, skin tissue culture may fail to show fungal growth. A diagnosis of a DCFI and initiation of appropriate treatment should always be considered in spite of discordant results.

Candida norvegensis fungemia in a liver transplant recipient

BACKGROUND

The incidence of candidemia due to non-Candida albicans Candida species has been progressively increasing in recent years. The use of fluconazole as antifungal prophylaxis has been described as a risk factor for the development of infections by fluconazole resistant Candida strains. We report a case of Candida norvegensis bloodstream infection in a liver transplant recipient.

CASE REPORT

A 61-year-old man, who received a third liver allograft and became worse with the onset of ischemic cholangiopathy and recurrent episodes of cholangitis, was admitted to our hospital due to the development of intra-abdominal abscesses. He received multiple antibiotic schemes, and after 3 months he was discharged, maintaining parenteral antibiotic at home. While he was on fluconazole prophylaxis, a breakthrough candidemia due to C. norvegensis occurred. In vitro susceptibilities of the isolate to several antifungal agents were as follows: amphotericin B MIC 0.5 mg/l, flucytosine 64 mg/l, fluconazole 64 mg/l, itraconazole 4 mg/l, voriconazole 0.75 mg/l, and caspofungin 0.047 mg/l. He was treated with anidulafungin with resolution of candidemia.

CONCLUSIONS

The use of fluconazole for antifungal prophylaxis may lead to the emergence of fluconazole-resistant Candida infections, with C. norvegensis being a possible emerging pathogen in organ transplant recipients.

Aspergillus tracheobronchitis causing subtotal tracheal stenosis in a liver transplant recipient

Invasive aspergillosis is recognized as one of the most significant opportunistic infections after liver transplantation. Diagnosis of invasive aspergillosis in transplant recipients has been proven to be challenging, and optimal approach to the treatment of invasive aspergillosis is still controversial. We here present an unusual case of Aspergillus tracheobronchitis in the setting of liver transplantation. A 47-year-old female patient with persistent dry cough after liver transplantation developed respiratory insufficiency and was readmitted to the intensive care unit 55 days after liver transplantation. A CT scan revealed subtotal tracheal stenosis; bronchoscopy was performed, and extended white mucus coverings causative of the tracheal stenosis were removed. Microbiological assessment isolated Aspergillus fumigatus. The diagnosis was obstructive Aspergillus tracheobronchitis. The patient was started on a treatment of voriconazole 200 mg orally twice daily, adjusted to a trough level of 1-4 mg/L. For further airway management, a tracheal stent had to be implanted. The patient is alive and well 28 months after liver transplantation. Invasive aspergillosis should be considered a possible etiology in liver transplant patients presenting with unspecific symptoms such as persistent dry cough. Optimal strategies for improved and early diagnosis as well as prophylaxis need to be defined.

Antifungal agents from Pseudallescheria boydii SNB-CN73 isolated from a Nasutitermes sp. termite

Defense mutualisms between social insects and microorganisms have been described in the literature. The present article describes the discovery of a Pseudallescheria boydii strain isolated from Nasutitermes sp. The microbial symbiont produces two antifungal metabolites: tyroscherin and N-methyltyroscherin, a compound not previously described in the literature. Methylation of tyroscherin has confirmed the structure of N-methyltyroscherin. Both compounds are effective antifungal agents with favorable selectivity indices for Candida albicans and Trichophyton rubrum.

Emerging systemic fungal infections

Systemic mycoses are a heterogeneous group of infections caused by different species of fungi that mainly affect individuals with primary or secondary alterations of immunity. In recent years, there has been an increase in the incidence of infections related to migration, AIDS, and other causes of immunosuppression, such as solid organ and bone marrow transplantation; oncological, hematological, and autoimmune diseases; and the use of new drugs. In this paper, we outline the microbiological and epidemiological characteristics of 3 fungi: Aspergillus spp, Fusarium spp, and Penicillium spp. We describe the clinical manifestations of disease with emphasis on those that should alert the dermatologist to make an early diagnosis. We detail the various tools for early diagnosis, prevention, and the epidemiology of different antifungals available for treatment and their mechanism of action and therapeutic efficacy.

Cytomegalovirus and Aspergillus spp. coinfection in organ transplantation: a case report and review of the literature

With the advent of potent immunosuppressive options, acute rejection episodes have decreased at the expense of increased incidence of opportunistic infections in solid organ recipients. In the absence of any preventive therapy, 30–75 % of transplant recipients develop cytomegalovirus (CMV) infection. Candida spp. and Aspergillus spp. account for more than 80 % of invasive fungal infections in solid organ recipients. This co-occurrence of two commonly seen opportunistic infections may end up in fatality. Here, we present a case of concomitant Aspergillus spp. and CMV infection and discuss the relevant literature. A 54-year-old male patient presented with fever, shortness of breath, and chest pain on the 9th posttransplant week after renal transplantation. CMV-DNA by polymerase chain reaction (PCR) was 1,680,000 copies/ml, thus, valganciclovir dose was increased. There were inspiratory crackles at both lung bases, and chest computed tomography (CT) revealed multiple fungal balls throughout the right lung. Galactomannan antigen was positive, and voriconazole and other antimicrobials were subsequently added to the treatment. At the end of the therapy, on control CT, pneumonic consolidation had disappeared, sputum cultures didn’t show Aspergillus spp., and CMV-DNA reduced to 700 copies/ml. The patient showed a favorable clinical response to combined treatment; fever, dyspnea, and pleuritic chest pain disappeared. Both CMV disease and aspergillosis may present as pulmonary disease; thus, the characterization of one may not preclude the search for the other and the timely initiation of treatment is of paramount importance for good outcomes.

Managing complications following lung transplantation

Lung transplantation has become a proven therapeutic option for patients with end-stage lung disease, extending life and providing improved quality of life to those who otherwise would continue to be breathless and oxygen-dependent. Over the past 20 years, considerable experience has been gained in understanding the multitude of medical and surgical issues that impact upon patient survival. Today, clinicians have an armamentarium of tools to manage diverse problems such as primary graft dysfunction, acute and chronic allograft rejection, airway anastomotic issues, infectious complications, renal dysfunction, diabetes and osteoporosis, hematological and gastrointestinal problems, malignancy, and other unique issues that confront immunosuppressed solid organ transplant recipients.

Fungal infection in solid organ recipients

In solid organ recipients, as with other immunosuppressed patients, infections by Candida spp. and Aspergillus spp. are the most frequent invasive mycoses. Infections by Cryptococcus spp. and fungi of the Mucorales order are less common. Infections by Fusarium spp. and Scedosporium spp. are very uncommon, except in patients undergoing hematopoietic stem cell transplant and patients with prolonged neutropenia. The risk factors for fungal infection are immunosuppression, surgery, viral co-infection, and environmental exposure. Diagnosis is challenging: blood culture is of little use, except in candidiasis and cryptococcosis, and the poor accuracy of antigen-based techniques, except in cryptococcosis, favors widespread use of empirical therapy. A delay in the initiation of therapy increases the already high mortality of these infections. The agents used to treat fungal infection are azoles, echinocandins, and lipid amphotericin. Administration depends on antifungal activity, drug-drug interactions with calcineurin inhibitors, and safety profiles (effects on grafts and other side effects).

Emerging fungal infections

Trends in Medical Mycology is one of the most attractive international meetings completely dedicated to clinical and fundamental research in the field of medical mycology. It is organized by the European Confederation of Medical Mycology and the Infectious Diseases Group of the European Organization for Research and Treatment of Cancer. Approximately 1500 participants, mainly microbiologists, clinicians and basic researchers, from more than 40 countries exchanged the most important advances in mycology from basic science to clinical research. A quick focus on some relevant clinical presentations is presented here.

Emerging fungal infections in immunocompromised patients

Invasive fungal infections are infections of importance and are increasing in incidence in immunocompromised hosts such as patients who have had hematopoietic stem cell and solid organ transplants. Despite our expanded antifungal armamentarium, these infections cause considerable morbidity and mortality. Indeed, certain trends have emerged in these invasive fungal infections: a rise in the incidence of invasive mold infections, an increase in the non-albicans strains of Candida spp. causing invasive disease and, finally, the emergence of less susceptible fungal strains that are resistant to the broader-spectrum antifungal agents due to overutilization of these agents. Clinicians must recognize the patient groups that are potentially at risk for these invasive fungal infections, as well as the risk factors for such infections. By using more sensitive nonculture-based diagnostic techniques, appropriate therapy may be initiated earlier to enhance survival in these immunocompromised patient populations.

Aspergillus spondylodiscitis in solid organ transplant recipients

BACKGROUND

Transplantation practices have had a significant effect on the epidemiology of invasive Aspergillosis. Aspergillus spondylodiscitis is rare in transplant recipients. The optimal treatment has yet to be defined because of the rarity of such cases. This article reviews the available literature on Aspergillus spondylodiscitis in solid organ transplant recipients and provides recommendations on its management.

METHODS

We identified 15 cases of Aspergillus spondylodiscitis in transplant recipients. Most patients were heart transplant recipients. Back pain was the mode of presentation in all patients. Most cases were afebrile. The dominant location was the lumbar spine.

RESULTS

Aspergillus fumigatus was responsible for 84.62% of cases and A flavus for 15.38%. The overall recovery rate was 66.67%. Delay in diagnosis remained a major impediment to the successful treatment of spinal aspergillosis. Treatment included antifungal therapy alone or combined with surgery. Initial therapy with voriconazole could lead to better curative effects.

CONCLUSION

Combined medical and operative interventions are recommended for treatment.

[Guidelines for the treatment of invasive fungal disease by Aspergillus spp. and other fungi issued by the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC). 2011 Update]

The guidelines on the treatment of invasive fungal disease by Aspergillus spp. and other fungi issued by the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) are presented. These recommendations are focused on four clinical categories: oncology-haematology patients, solid organ transplant recipients, patients admitted to intensive care units, and children. An extensive review is made of therapeutical advances and scientific evidence in these settings. These guidelines have been prepared according the SEIMC consensus rules by a working group composed of specialists in infectious diseases, clinical microbiology, critical care medicine, paediatrics and oncology-haematology. Specific recommendations on the prevention of fungal infections in these patients are included.

Search for antifungal compounds from the wood of durable tropical trees

Research on antifungal compounds from the durable wood from French Guiana Amazonian forest trees highlights the correlation between the activity of their extracts against wood-rotting fungi and human pathogens. The fractionation of an ethyl acetate extract of Sextonia rubra wood led to the isolation of rubrenolide (1) and rubrynolide (2). The potential of compounds 1 and 2 is described through the evaluation of their activity against 16 pathogenic fungi and their cytotoxicity toward NIH-3T3 mammalian fibroblast cells.

Fungal infections in transplant and oncology patients

Recent shifts in the epidemiology of invasive fungal infections (IFIs) among transplant and oncology populations have led to new recommendations on treatment; however, they have also brought new controversies. New pharmacologic therapies are being studied and guidelines for management of several IFIs have been changed accordingly. More information is being discovered about unique genetic factors that put some transplant recipients at greater risk than others for fungal infection. The role of immunomodulation continues to be investigated, and the delicate balance of maintaining some immune integrity while assuring protection of the graft remains critical. For transplant and oncology patients, the diagnosis and management of IFIs remain challenging, and improving outcomes depends on continued progress in all of these arenas. This article highlights recent advances and important factors to consider when treating transplant and oncology patients with IFIs.

Caspofungin for post solid organ transplant invasive fungal disease: results of a retrospective observational study

M. Winkler, J. Pratschke, U. Schulz, S. Zheng, M. Zhang, W. Li, M. Lu, D. Sgarabotto, G. Sganga, P. Kaskel, S. Chandwani, L. Ma, J. Petrovic, M. Shivaprakash. Caspofungin for post solid organ transplant invasive fungal disease: results of a retrospective observational study. Transpl Infect Dis 2010: 12: 230–237. All rights reserved

[Current status of invasive fungal infections. New diagnostic techniques and antifungal agents]

In the last few years, major advances in the treatment of transplant recipients, with hemato-oncological diseases or admitted to the intensive care unit, has been accompanied by an increase in classical fungal infections and by the emergence of uncommon fungal infections. Despite the development of new diagnostic techniques such as galactomannan detection and the availability of new antifungal agents, these opportunistic infections continue to pose a diagnostic challenge, prolong length of hospital stay, and increase costs. In addition, mortality from these infections is high. The present chapter provides a brief review of the epidemiology of these infections, diagnostic advances, and the new antifungal agents that have been developed in the last few years.

Incidence and clinical predictors of primary opportunistic deep cutaneous mycoses in solid organ transplant recipients: a multicenter cohort study

BACKGROUND

Primary opportunistic deep cutaneous fungal infections may cause significant morbidity and mortality in solid organ transplant recipients (OTR), but no data exist about their incidence, timing, and clinical predictors in a long-term follow-up.

PATIENTS AND METHODS

A series of 3293 consecutive OTR including 1991 kidney, 929 heart, and 373 liver transplant recipients were enrolled. Patients were regularly followed up since time at transplantation (mean 5.5 yr +/-5.9 SD) and primary opportunistic fungal infections registered. Persons-year at risk (PYs), incidence rates (IR), incidence rate ratios (IRR), and 95% confidence intervals were computed.

RESULTS

Twenty-two cases of deep cutaneous mycoses were detected, (IR 1.2 cases per 1000 PYs) after a mean follow-up time since transplantation of 2.5 yr +/- 2.0 SD (median 1.8 yr). Six patients had subsequent systemic involvement and three patients died of systemic dissemination. A higher risk for mycoses was observed in the first two yr after transplantation, (IRR 35.9, p < 0.0001), in renal transplant recipients (IRR 5.1 p = 0.030), and in patients transplanted after the age of 50 (IRR 11.5 p = 0.020).

CONCLUSIONS

Primary deep cutaneous opportunistic mycoses in OTR occur mainly in the first two yr after transplantation, in renal transplant recipients, and in older patients.

Invasive mold infections in iatrogenically immunocompromised children: an eight-yr review

IMI are emerging as an important cause of mortality and morbidity among the growing number of immunocompromised children. A retrospective chart review was performed in all patients with a proven diagnosis of IMI over an eight-yr period (1997-2004) at The Hospital for Sick Children, Toronto, Canada to document the incidence, clinical spectrum, microbiology, treatment, and outcome of pediatric IMI. Twenty-eight patients developed IMI over the study period (10 cancer, 12 HCT, and six SOT patients). IMI occurred in 0.51%, 2.2% and 3.2% after a median time of 118, 60 and 71 days, among cancer, HCT and SOT recipients, respectively. Aspergillus spp. infection was diagnosed most commonly (23 patients) and the most common site of infection was the lung (21 patients). Patients at increased risk included those with acute myelogenous leukemia, allogeneic unrelated HCT recipients, graft-versus-host disease, and lung transplant recipients. The mortality after one yr was 60% among cancer patients, 58% among HCT patients, and 16% among SOT patients.

Avoiding pitfalls: what an endoscopist should know in liver transplantation--part II

Over the last decade the number of patients undergoing transplantation has increased. At the same time, effective peri- and postoperative care and better surgical techniques have resulted in greater numbers of recipients achieving long-term survival. Identification and effective management in the form of adequate treatment is essential, since any delay in diagnosis or treatment may result in graft loss or serious threat to patient's life. Various aspects of endoscopic findings that can be commonly encountered among liver transplant recipients are discussed herein. Topics include: persistent and/or recurrent esophageal varices, reflux, Candida or cytomegalovirus (CMV) esophagitis, esophageal neoplasms, posttransplant peptic ulcer, biliary complications, posttransplant lymphoproliferative disorder (PTLD), Kaposi's sarcoma, CMV colitis and inflammatory bowel disease, colonic neoplasms, Clostridium difficile infection, and graft versus host disease (GVHD).

Reduced post-operative neutrophil activation in liver transplant recipients suffering from post-hepatitic cirrhosis

BACKGROUND

It has been supposed that liver transplant recipients with hepatitis C virus infection have a higher incidence of infectious complications after transplantation. This study was designed to investigate whether neutrophil function is immediately affected by liver transplantation.

METHODS

Biochemical values, plasma levels of myeloperoxidase (MPO), hydrogen peroxide production of neutrophils and neutrophil-platelet complexes were analyzed in 32 patients who underwent liver transplantation and 20 healthy volunteers.

RESULTS

MPO levels were significantly increased 24 h after reperfusion. In post-hepatitic patients levels were significantly lower three d up to one wk post-transplant than in patients due to other liver diseases. One wk post-operatively the respiratory burst activity following N-formyl-methionyl-leucylphenylalanine (fMLP) or (tumor necrosis factor-alpha) TNF-alpha/fMLP stimulation was depressed in post-hepatitic recipients. Respiratory burst stimulated with phorbol 12-myristate 13-acetate in these patients was increased one wk after transplantation. One d after transplantation the neutrophil-platelet complexes decreased significantly throughout the post-operative period.

CONCLUSIONS

The results of this study suggest a reduced post-operative neutrophil activation in liver transplant recipients suffering from post-hepatitic cirrhosis compared to cirrhosis due to other causes. We hypothesized that neutrophil dysfunction in those patients depends on the underlying disease with an increased susceptibility to bacterial or fungal infections.

Dose tolerability of chronically inhaled voriconazole solution in rodents

Invasive pulmonary aspergillosis (IPA) is a fungal disease of the lung associated with high mortality rates in immunosuppressed patients despite treatment. Targeted drug delivery of aqueous voriconazole solutions has been shown in previous studies to produce high tissue and plasma drug concentrations as well as improved survival in a murine model of IPA. In the present study, rats were exposed to 20 min nebulizations of normal saline (control group) or aerosolized aqueous solutions of voriconazole at 15.625 mg (low dose group) or 31.25mg (high dose group). Peak voriconazole concentrations in rat lung tissue and plasma after 3 days of twice daily dosing in the high dose group were 0.85+/-0.63 microg/g wet lung weight and 0.58+/-0.30 microg/mL, with low dose group lung and plasma concentrations of 0.38+/-0.01 microg/g wet lung weight and 0.09+/-0.06 microg/mL, respectively. Trough plasma concentrations were low but demonstrated some drug accumulation over 21 days of inhaled voriconazole administered twice daily. Following multiple inhaled doses, statistically significant but clinically irrelevant abnormalities in laboratory values were observed. Histopathology also revealed an increase in the number of alveolar macrophages but without inflammation or ulceration of the airway, interstitial changes, or edema. Inhaled voriconazole was well tolerated in a rat model of drug inhalation.