A multicenter study of histoplasmosis and blastomycosis after solid organ transplantation

Histoplasmosis around the world: A global perspective on the presentation, virulence factors, and treatment of histoplasmosis

Histoplasmosis is a systemic infection caused by an endemic dimorphic fungus, Histoplasma capsulatum. Though prevalent in the eastern United States of America, near the Ohio and Mississippi River Valleys, the evidence underlying the global prevalence of histoplasmosis, especially in immunocompromised populations, is underappreciated. This article highlights the global epidemiology, risk factors, microbiology and pathophysiological characteristics, pulmonary and extrapulmonary manifestations, prevention measures, radiographic patterns, diagnostic techniques, and antifungal treatment approaches for Histoplasma capsulatum.

Genotypic diversity, virulence, and molecular genetic tools in Histoplasma

SUMMARYHistoplasmosis is arguably the most common fungal respiratory infection worldwide, with hundreds of thousands of new infections occurring annually in the United States alone. The infection can progress in the lung or disseminate to visceral organs and can be difficult to treat with antifungal drugs. Histoplasma, the causative agent of the disease, is a pathogenic fungus that causes life-threatening lung infections and is globally distributed. The fungus has the ability to germinate from conidia into either hyphal (mold) or yeast form, depending on the environmental temperature. This transition also regulates virulence. Histoplasma and histoplasmosis have been classified as being of emergent importance, and in 2022, the World Health Organization included Histoplasma as 1 of the 19 most concerning human fungal pathogens. In this review, we synthesize the current understanding of the ecological niche, evolutionary history, and virulence strategies of Histoplasma. We also describe general patterns of the symptomatology and epidemiology of histoplasmosis. We underscore areas where research is sorely needed and highlight research avenues that have been productive.

Clinical Characteristics and Outcomes of Endemic Mycoses After Solid Organ Transplantation: A Comprehensive Review

Background

Geographically endemic fungi can cause significant disease among solid organ transplant (SOT) recipients. We provide an update on the epidemiology, clinical presentation, and outcomes of 5 endemic mycoses in SOT recipients.

Methods

Multiple databases were reviewed from inception through May 2023 using key words for endemic fungi (eg, coccidioidomycosis or Coccidioides, histoplasmosis or Histoplasma, etc). We included adult SOT recipients and publications in English or with English translation.

Results

Among 16 cohort studies that reported on blastomycosis (n = 3), coccidioidomycosis (n = 5), histoplasmosis (n = 4), and various endemic mycoses (n = 4), the incidence rates varied, as follows: coccidioidomycosis, 1.2%-5.8%; blastomycosis, 0.14%-0.99%; and histoplasmosis, 0.4%-1.1%. There were 204 reports describing 268 unique cases of endemic mycoses, including 172 histoplasmosis, 31 blastomycosis, 34 coccidioidomycosis, 6 paracoccidioidomycosis, and 25 talaromycosis cases. The majority of patients were male (176 of 261 [67.4%]). Transplanted allografts were mostly kidney (192 of 268 [71.6%]), followed by liver (n = 39 [14.6%]), heart (n = 18 [6.7%]), lung (n = 13 [4.9%]), and combined kidney-liver and kidney-pancreas (n = 6 [2.7%]). In all 5 endemic mycoses, most patients presented with fever (162 of 232 [69.8%]) and disseminated disease (179 of 268 [66.8%]). Cytopenias were frequently reported for histoplasmosis (71 of 91 [78.0%]), coccidioidomycosis (8 of 11 [72.7%]) and talaromycosis (7 of 8 [87.5%]). Graft loss was reported in 12 of 136 patients (8.8%). Death from all-causes was reported in 71 of 267 (26.6%); half of the deaths (n = 34 [50%]) were related to the underlying mycoses.

Conclusions

Endemic mycoses commonly present with fever, cytopenias and disseminated disease in SOT recipients. There is a relatively high all-cause mortality rate, including many deaths that were attributed to endemic mycoses.

Histoplasmosis in Solid Organ Transplantation

Histoplasma capsulatum, the etiological agent for histoplasmosis, is a dimorphic fungus that grows as a mold in the environment and as a yeast in human tissues. It has a broad global distribution with shifting epidemiology during recent decades. While in immunocompetent individuals infection is usually self-resolving, solid organ transplant recipients are at increased risk of symptomatic disease with dissemination to extrapulmonary tissue. Diagnosis of histoplasmosis relies on direct observation of the pathogen (histopathology, cytopathology, and culture) or detection of antigens, antibodies, or nucleic acids. All transplant recipients with histoplasmosis warrant therapy, though the agent of choice and duration of therapy depends on the severity of disease. In the present article, we describe the pathogenesis, epidemiology, clinical manifestations and management of histoplasmosis in solid organ transplant recipients.

Blastomycosis: A Review of Mycological and Clinical Aspects

Blastomycosis is caused by a thermally dimorphic fungus that thrives in moist acidic soil. Blastomyces dermatitidis is the species responsible for most infections in North America and is especially common in areas around the Great Lakes, the St. Lawrence Seaway, and in several south-central and southeastern United States. Other Blastomyces species have more recently been discovered to cause disease in distinct geographic regions around the world. Infection almost always occurs following inhalation of conidia produced in the mold phase. Acute pulmonary infection ranges from asymptomatic to typical community-acquired pneumonia; more chronic forms of pulmonary infection can present as mass-like lesions or cavitary pneumonia. Infrequently, pulmonary infection can progress to acute respiratory distress syndrome that is associated with a high mortality rate. After initial pulmonary infection, hematogenous dissemination of the yeast form of Blastomyces is common. Most often this is manifested by cutaneous lesions, but osteoarticular, genitourinary, and central nervous system (CNS) involvement also occurs. The diagnosis of blastomycosis can be made by growth of the mold phase of Blastomyces spp. in culture or by histopathological identification of the distinctive features of the yeast form in tissues. Detection of cell wall antigens of Blastomyces in urine or serum provides a rapid method for a probable diagnosis of blastomycosis, but cross-reactivity with other endemic mycoses commonly occurs. Treatment of severe pulmonary or disseminated blastomycosis and CNS blastomycosis initially is with a lipid formulation of amphotericin B. After improvement, therapy can be changed to an oral azole, almost always itraconazole. With mild to moderate pulmonary or disseminated blastomycosis, oral itraconazole treatment is recommended.

Osteoarticular Mycoses

Osteoarticular mycoses are chronic debilitating infections that require extended courses of antifungal therapy and may warrant expert surgical intervention. As there has been no comprehensive review of these diseases, the International Consortium for Osteoarticular Mycoses prepared a definitive treatise for this important class of infections. Among the etiologies of osteoarticular mycoses are Candida spp., Aspergillus spp., Mucorales, dematiaceous fungi, non-Aspergillus hyaline molds, and endemic mycoses, including those caused by Histoplasma capsulatum, Blastomyces dermatitidis, and Coccidioides species. This review analyzes the history, epidemiology, pathogenesis, clinical manifestations, diagnostic approaches, inflammatory biomarkers, diagnostic imaging modalities, treatments, and outcomes of osteomyelitis and septic arthritis caused by these organisms. Candida osteomyelitis and Candida arthritis are associated with greater events of hematogenous dissemination than those of most other osteoarticular mycoses. Traumatic inoculation is more commonly associated with osteoarticular mycoses caused by Aspergillus and non-Aspergillus molds. Synovial fluid cultures are highly sensitive in the detection of Candida and Aspergillus arthritis. Relapsed infection, particularly in Candida arthritis, may develop in relation to an inadequate duration of therapy. Overall mortality reflects survival from disseminated infection and underlying host factors.

Updates on Histoplasmosis in Solid Organ Transplantation

Purpose of Review

Recent Findings

Summary

Fungal Infections in Lung Transplantation

Purpose of Review

We aim to understand the most common fungal infections associated with the post-lung transplant period, how to diagnose, treat, and prevent them based on the current guidelines published and our center’s experience.

Recent Findings

Different fungi inhabit specific locations. Diagnosis of invasive fungal infections (IFIs) depends on symptoms, radiologic changes, and a positive microbiological or pathology data. There are several molecular tests that have been used for diagnosis. Exposure to fungal prophylaxis can predispose lung transplant recipients to these emerging molds. Understanding and managing medication interactions and drug monitoring are essential in successfully treating IFIs.

Summary

With the increasing rate of lung transplantations being performed, and the challenges posed by the immunosuppressive regimen, understanding the risk and managing the treatment of fungal infections are imperative to the success of a lung transplant recipient. There are many ongoing clinical trials being conducted in hopes of developing novel antifungals.

Case report: Histoplasmosis presenting as asymptomatic hypercalcemia detected on routine laboratory testing in a pediatric kidney transplant recipient

Among all infections occurring in pediatric kidney transplant recipients, approximately 1%-5% are fungal. Most fungal infections occur in the first 6 months following kidney transplantation. We present the case of a 15-year-old boy with a history of a kidney transplant 4 years ago, who was found to have asymptomatic moderate hypercalcemia on routine laboratory testing, along with an acute deterioration of his kidney function markers. The cause of his acute kidney injury was likely related to hypercalcemia. An extensive workup for hypercalcemia revealed infection with Histoplasma capsulatum (histoplasmosis) with multiple pulmonary nodules. Hypercalcemia that was initially refractory to medical management resolved after initiating the antifungal treatment. Fungal granulomatous infections such as histoplasmosis should be considered in the differential diagnosis of hypercalcemia in an asymptomatic pediatric kidney transplant recipient.

COVID-19 associated with disseminated histoplasmosis in a kidney transplant patient

We report a case of disseminated histoplasmosis and COVID-19 infection in a renal transplant recipient in Argentina. The patient exhibited respiratory symptoms, and a chest computed tomography scan (CT) showed multiple bilateral centrilobular opacities with a tree-in-bud pattern in both lobes. The patient was initially treated as having bacterial community-acquired pneumonia, and then tuberculosis. A month later, histoplasmosis was diagnosed, and Histoplasma capsulatum LAmB clade was isolated from sputum, skin and oral lesions. The patient was hospitalized and treatment was started with intravenous liposomal amphotericin B. During the course of the antifungal therapy the respiratory symptoms worsened, a new chest CT showed a unilateral lesion with a ground glass appearance and SARS-CoV-2 was detected in a new nasopharyngeal sample. In addition, plasma therapy was administered, and the immunosuppressive regimen was adjusted (everolimus was interrupted, mycophenolate mofetil reduced, and meprednisone increased). Finally, the patient's progress was favorable and was discharged after five days on oral itraconazole treatment for histoplasmosis.

Risk factors of severe blastomycosis and comparison of diagnosis and outcomes between immunocompetent and immunocompromised patients

BACKGROUND

Blastomycosis is an endemic fungal infection that causes pulmonary and systemic disease. It can occur irrespective of the patient's immune status. The risk factors associated with the severity of the disease are not well studied.

METHODS

This is a retrospective study of patients admitted with blastomycosis at the University of Kentucky Hospital from 2004 to 2019. Logistic regression was used to identify variables associated with severe blastomycosis.

RESULTS

A total of 76 patients were identified; 22 (28.9%) had at least one immunosuppressive condition. Pulmonary blastomycosis was reported in 49/76 (65%) of the patients and disseminated infection in 27/76 (35.5%). All diagnostic tests were not significantly different in diagnostic results in immunocompromised vs immunocompetent patients. Cultures and histopathology were positive in 56/61 (91.8%) and 54/63 (85.7%) respectively. Blastomyces or Histoplasma antigen test was positive in 13/17 (76.4%) in immunocompromised patients compared to 26/42 (61.9%) in immunocompetent patients. Immunocompromised patients were more likely to be admitted to the hospital and ICU compared to immunocompetent patients. In the multivariate analysis, pulmonary multilobar disease (RR 5.68; 95% CI 2.13-15.15), obesity (RR 2.39; 95% CI 1.26-4.51), diabetes mellitus (RR 3.50; 95% CI 1.38-8.90) and immunosuppression (RR 2.28; 95% CI 1.14-4.56) were significant independent risk factors for severe blastomycosis. Inpatient mortality proportion was higher in immunocompromised patients but not statistically significant.

CONCLUSION

Pulmonary multilobar disease, obesity, diabetes mellitus and immunosuppression were risk factors associated with severe blastomycosis. Immunocompromised patients required more frequent hospitalisations compared to immunocompetent patients.

Blastomycosis in solid organ transplant recipients-A retrospective series from southeastern Wisconsin

Blastomycosis is a fungal infection caused primarily by Blastomyces dermatitis. The fungus is endemic to the Ohio, Mississippi, and St. Lawrence River areas of the United States. Organ transplant recipients are at risk of blastomycosis due to pharmacologic immunosuppression. Over a 20-year period, 30 cases of blastomycosis post-solid organ transplantation were identified at our center. The cumulative incidence of blastomycosis among SOT recipients was 0.99%. There was a male predominance (70% male) and a median age of 59 at the time of diagnosis. Regarding transplant type, 23 patients received kidney transplants, 4 received liver transplants, 2 received pancreas transplants and 1 received a heart transplant. Median time to blastomycosis identification post-transplant was 67.8 months (range: 1-188 months). Amphotericin B was used as initiation therapy in most cases, followed by itraconazole, voriconazole, or in select cases fluconazole or posaconazole maintenance therapy. Regarding comorbid conditions, 87% of patients had diabetes, 50% had congestive heart failure, and 20% had chronic pulmonary disease. Nine patients (30%) developed blastomycosis-related acute respiratory distress syndrome, 33% of these died with a median time to death of 22 days (range 20 days to 2 months); these were the only deaths attributable to blastomycosis.

Immunology of Fungal Infections

Complex processes mediate immunity to fungal infections. Responses vary depending on the organism, morphogenic state, and infection site. Innate immune effectors such as epithelia, phagocytes, and soluble molecules detect pathogens, kill fungi, release cytokines, and prime the adaptive response. Adaptive responses to mucocutaneous or invasive disease are markedly different but intersect at certain pathways (molecules required for IL-23 and IL-12 signaling). Many of these pathways have been elucidated from the study of inborn errors of immunity. This review explores the general aspects of antifungal immunity and delves into the mechanisms that mediate protection from frequently encountered fungi.

Fungal pneumonia in kidney transplant recipients

Fungal pneumonia is a dreaded complication encountered after kidney transplantation, complicated by increased mortality and often associated with graft failure. Diagnosis can be challenging because the clinical presentation is non-specific and diagnostic tools have limited sensitivity and specificity in kidney transplant recipients and must be interpreted in the context of the clinical setting. Management is difficult due to the increased risk of dissemination and severity, multiple comorbidities, drug interactions and reduced immunosuppression which should be applied as an important adjunct to therapy. This review will focus on the main causes of fungal pneumonia in kidney transplant recipients including Pneumocystis, Aspergillus, Cryptococcus, mucormycetes and Histoplasma. Epidemiology, clinical presentation, laboratory and radiographic features, specific characteristics will be discussed with an update on diagnostic procedures and treatment.

Blastomycosis

Blastomycosis is the fungal disease caused by thermally dimorphic fungi in the genus Blastomyces, with B dermatitidis complex causing most cases. It is considered hyperendemic in areas adjacent to the Great Lakes and along the St. Lawrence, Mississippi, and Ohio rivers, but definitive geographic distribution of blastomycoses remains obscure. Clinical presentation is variable. Disseminated blastomycosis with extrapulmonary manifestations is more common in immunosuppressed individuals. Culture positivity is required for definitive diagnosis, but compatible histology is often sufficient for presumptive diagnosis and initiation of treatment. Treatment should be provided to all symptomatic cases to prevent progression or recurrence.

Clinical Manifestations and Outcomes in Immunocompetent and Immunocompromised Patients With Blastomycosis

BACKGROUND

Blastomyces is a dimorphic fungus that infects persons with or without underlying immunocompromise. To date, no study has compared the clinical features and outcomes of blastomycosis between immunocompromised and immunocompetent persons.

METHODS

A retrospective study of adult patients with proven blastomycosis from 2004-2016 was conducted at the University of Wisconsin. Epidemiology, clinical features, and outcomes were analyzed among solid-organ transplantation (SOT) recipients, persons with non-SOT immunocompromise (non-SOT IC), and persons with no immunocompromise (NIC).

RESULTS

A total of 106 cases met the inclusion criteria including 74 NIC, 19 SOT, and 13 non-SOT IC (malignancy, HIV/AIDS, idiopathic CD4+ lymphopenia). The majority of patients (61.3%) had at least 1 epidemiologic risk factor for acquisition of Blastomyces. Pneumonia was the most common manifestation in all groups; however, immunocompromised patients had higher rates of acute pulmonary disease (P = .03), more severe infection (P = .007), respiratory failure (P = .010), and increased mortality (P = .02). Receipt of SOT primarily accounted for increased severity, respiratory failure, and mortality in immunosuppressed patients. SOT recipients had an 18-fold higher annual incidence of blastomycosis than the general population. The rate of disseminated blastomycosis was similar among NIC, SOT, and non-SOT IC. Relapse rates were low (5.3-7.7%).

CONCLUSIONS

Immunosuppression had implications regarding the acuity, severity, and respiratory failure. The rate of dissemination was similar across the immunologic spectrum, which is in sharp contrast to other endemic fungi. This suggests that pathogen-related factors have a greater influence on dissemination for blastomycosis than immune defense.

Granulomatous lung disease: clinical aspects

INTRODUCTION

Granulomatous lung diseases (GLD) are heterogeneous group of diseases that can be broadly categorized as infectious or noninfectious. This distinction is extremely important, as the misdiagnosis of a GLD can have serious consequences. In this manuscript, we describe the clinical manifestations, histopathology, and diagnostic approach to GLD. We propose an algorithm to distinguish infectious from noninfectious GLD.

AREAS COVERED

We have searched PubMed and Medline database from 1950 to December 2019, using multiple keywords as described below. Major GLDs covered include those caused by mycobacteria and fungi, sarcoidosis, hypersensitivity pneumonitis, and vasculidities.

EXPERT OPINION

The cause of infectious GLD is usually identified through microbiological culture and molecular techniques. Most noninfectious GLD are diagnosed by clinical and laboratory criteria, often with exclusion of infectious pathogens. Further understanding of the immunopathogenesis of the granulomatous response may allow improved diagnosis and treatment of GLD.

Disseminated histoplasmosis in a kidney transplant patient

Patients with impaired cell-mediated immunity have a higher risk of developing histoplasmosis; however, histoplasmosis after solid organ transplantation is rare. In Thailand, histoplasmosis cases are sporadic, and most cases are associated with human immunodeficiency virus (HIV) infection. Herein, we report a case of disseminated histoplasmosis in a kidney transplant Thai recipient diagnosed by fungal staining of fungal culture from bronchoalveolar lavage and bone marrow biopsy. Liposomal amphotericin B was given followed by oral itraconazole. The patient's clinical condition was improved; however, his graft function was irreversibly declined. The majority of histoplasmosis cases after solid organ transplant presented with disseminated disease with pulmonary involvement. Even in a non-endemic area of histoplasmosis, suspected cases should be early diagnosed and promptly managed in order to reduce morbidity and mortality, especially in cell-mediated immunity defect patients like solid organ transplant recipients.

Urine antigen-negative disseminated histoplasmosis mimicking post-transplant lymphoproliferative disorder

A 50-year-old woman with a history of kidney transplant presented with 2 days of abdominal pain after 6 months of recurrent streptococcal pharyngitis, fevers, weight loss and a new rash on her chest and back. Her examination was notable for a unilateral tonsillar exudate and 2-3 mm pink papules with a fine scale over her chest and back. CT of the abdomen and chest demonstrated several large lymph nodes, and laboratory investigation revealed new cytopenias and elevated transaminases. Urine antigen testing for Histoplasma capsulatum was negative, but a fungal complement fixation panel was reactive for Histoplasma antibodies. Skin biopsy revealed intracellular organisms consistent with H. capsulatum She underwent treatment with liposomal amphotericin B but due to nephrotoxicity, drug interactions and worsening transaminitis, therapy was changed to itraconazole. The diagnosis and management of disseminated histoplasmosis presents multiple challenges, which are of particular importance in patients with a history of renal transplantation.

Histoplasma capsulatum presenting as generalized lymphadenopathy after renal transplantation

Histoplasma capsulatum is typically an indolent disease among immunocompetent patients. However, immunocompromised patients, such as solid organ transplant recipients, are at risk of developing severe histoplasmosis. Yet post-transplant histoplasmosis is a rare pathology, representing less than five percent of invasive fungal infections among transplant recipients. Furthermore, patients tend to present with nonspecific clinical symptoms, complicating timely diagnosis and delaying treatment. Disease features that may be more representative of H. capsulatum infection, such as anemia, leukopenia and pulmonary involvement are often not present until late in the disease course, when the patient is at greater risk of decompensation. Unlike H. capsulatum infections among immunocompetent hosts, extrapulmonary infection among immunocompromised hosts is more the rule than the exception. Treatment with liposomal amphotericin B followed by oral itraconazole is the standard therapy, but special considerations must be made for patients with hepatic and/or renal insufficiency, underlying cardiac abnormalities or malabsorptive pathologies and doses of immunosuppressants will need to be adjusted for drug interactions. Herein we present a case of H. capsulatum infection presenting with generalized lymphadenopathy post-renal transplant.

Pulmonary Blastomycosis Following Eculizumab Therapy in a Lung Transplant Recipient

Lung transplant recipients are at risk of developing many kinds of lung infection, such as community-acquired, nosocomial, opportunistic, and endemic. Here, we report a young lung transplant recipient who developed blastomycosis, which had most likely occurred following eculizumab treatment for atypical hemolytic uremia syndrome. We hypothesize that the agent interfering with C5 would influence the immune response against Blastomyces species. Although eculizumab has opened a new era for treatment of atypical hemolytic uremia syndrome and has led to the understanding that complementmediated pathology is needed, the risk of potentially fatal infections by blocking the complement pathway has not been fully elucidated. Careful follow-up and frequent tests to look for infections are needed after using this monoclonal antibody.

Central Nervous System Infection with Other Endemic Mycoses: Rare Manifestation of Blastomycosis, Paracoccidioidomycosis, Talaromycosis, and Sporotrichosis

The central nervous system (CNS) is not a major organ involved with infections caused by the endemic mycoses, with the possible exception of meningitis caused by Coccidioides species. When CNS infection does occur, the manifestations vary among the different endemic mycoses; mass-like lesions or diffuse meningeal involvement can occur, and isolated chronic meningitis, as well as widely disseminated acute infection that includes the CNS, are described. This review includes CNS infection caused by Blastomyces dermatitidis, Paracoccidioides brasiliensis, Talaromyces marneffei, and the Sporothrix species complex. The latter is not geographically restricted, in contrast to the classic endemic mycoses, but it is similar in that it is a dimorphic fungus. CNS infection with B. dermatitidis can present as isolated chronic meningitis or a space-occupying lesion usually in immunocompetent hosts, or as one manifestation of widespread disseminated infection in patients who are immunosuppressed. P. brasiliensis more frequently causes mass-like intracerebral lesions than meningitis, and most often CNS disease is part of disseminated infection found primarily in older patients with the chronic form of paracoccidioidomycosis. T. marneffei is the least likely of the endemic mycoses to cause CNS infection. Almost all reported cases have been in patients with advanced HIV infection and almost all have had widespread disseminated infection. Sporotrichosis is known to cause isolated chronic meningitis, primarily in immunocompetent individuals who do not have Sporothrix involvement of other organs. In contrast, CNS infection in patients with advanced HIV infection occurs as part of widespread disseminated infection.

Diagnosis and treatment of histoplasmosis in solid organ transplant patients

PURPOSE OF REVIEW

Unlike immunocompetent hosts, solid organ transplant (SOT) recipients with posttransplant histoplasmosis (PTH) often present with disseminated disease and have an attributable mortality of approximately 10%. In this review, we discuss currently available diagnostic tests and treatment strategies in PTH.

RECENT FINDINGS

None of the available tests have a 100% diagnostic accuracy. Histoplasma antigen assays are the most sensitive commercially available tests. However, crossreactivity of histoplasma antigen with aspergillus galactomannan and false positive histoplasma antigen tests because of rabbit antithymocyte globulin may cause difficulty in interpreting positive test results in transplant recipients. Molecular assays such as amplification and sequencing of 'panfungal' portions of the 28S ribosomal RNA from clinical specimens appear to be promising.Lipid formulations of amphotericin B and itraconazole are the drugs of choice in the treatment of PTH. Other extended spectrum azoles also appear to be effective, but, like itraconazole, problems with drug interactions and prolongation of the QTc interval (except for isavuconazole, which shortens the QTc interval) remain. Mycophenolate therapy is associated with severe disease and should be stopped during active disease and, if feasible, calcineurin inhibitors and steroids should be reduced.

SUMMARY

A combination of various tests (culture, antigen tests, nucleic amplification tests, etc.) should be used to optimize diagnostic yield. The role of unbiased next generation sequencing for early diagnosis and newer azoles in the treatment needs to be further explored.

Laryngeal histoplasmosis in a kidney transplant recipient

Histoplasma capsulatum is an endemic fungus that most oftenly causes a self-limiting illness but can result in severe infections in immunocompromised patients including pulmonary or extra-pulmonary disease. Rarely it can also cause a chronic progressive infection of the larynx. Herein, we report a case of laryngeal histoplasmosis in a kidney transplant patient who presented with progressive symptoms of several weeks of hoarseness, dysphagia and odynophagia. Laryngoscopic examination revealed thick plaques in the oropharynx with surrounding hyper-erythema and histopathology showed numerous intracellular yeasts forms consistent with H capsulatum. Patient was initiated on treatment with itraconazole. Infection of the larynx due to H capsulatum is highly uncommon and therefore can result in an inappropriate or delayed diagnosis. A review of literature showed four previously reported cases of laryngeal histoplasmosis in patients with solid organ transplant. This is the first case series of laryngeal histoplasmosis in transplant recipients.

Endemic fungal infections in solid organ transplant recipients-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 blastomycosis, histoplasmosis, and coccidioidomycosis in the pre- and post-transplant period. Though each of these endemic fungal infections has unique epidemiology and clinical manifestations, they all share a predilection for primary pulmonary infection and may cause disseminated infection, particularly in immunocompromised hosts. Culture remains the gold standard for definitive diagnosis, but more rapid diagnosis may be achieved with direct visualization of organisms from clinical specimens and antigen-based enzyme immunoassay assays. Serology is of limited utility in transplant recipients. The mainstay of treatment for severe infections remains liposomal amphotericin followed by a step-down azole therapy. Cases of mild to moderate severity with no CNS involvement may be treated with azole therapy alone. The newer generation azoles provide additional treatment options, but supported currently with limited clinical efficacy data. Azole therapy in transplant recipients presents a unique challenge owing to the drug-drug interactions with immunosuppressant agents. Therapeutic drug monitoring of azole levels is an essential component of effective and safe therapy. Infection prevention centers around minimizing epidemiological exposures, early clinical recognition, and azole prophylaxis in selected individuals.

Successful Treatment of Cutaneous Blastomycosis in a Renal Transplant Patient With BK Virus Infection: A Case Report

This is the first case report from Turkey to describe a renal transplant complicated by subcutaneous blastomycosis and BK infection. The cutaneous lesions were successfully treated with amphotericin B and fluconazole. The presence of BK infection led to graft failure. Infections with uncommonly seen organisms should be kept in mind due to the impaired T-cell immunity in transplantation.

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.

Infections in Liver Transplantation

Liver transplantation has become an important treatment modality for patients with end-stage liver disease/cirrhosis, acute liver failure, and hepatocellular carcinoma. Although surgical techniques and immunosuppressive regimens for liver transplantation have improved significantly over the past 20 years, infectious complications continue to contribute to the morbidity and mortality in this patient population. The use of standardized screening protocols for both donors and recipients, coupled with targeted prophylaxis against specific pathogens, has helped to mitigate the risk of infection in liver transplant recipients. Patients with chronic liver disease and cirrhosis have immunological deficits that place them at increased risk for infection while awaiting liver transplantation. The patient undergoing liver transplantation is prone to develop healthcare-acquired infections due to multidrug-resistant organisms that could potentially affect patient outcomes after transplantation. The complex nature of liver transplant surgery that involves multiple vascular and hepatobiliary anastomoses further increases the risk of infection after liver transplantation. During the early post-transplantation period, healthcare-acquired bacterial and fungal infections are the most common types of infection encountered in liver transplant recipients. The period of maximal immunosuppression that occurs at 1–6 months after transplantation can be complicated by opportunistic infections due to both primary infection and reactivation of latent infection. Severe community-acquired infections can complicate the course of liver transplantation beyond 12 months after transplant surgery. This chapter provides an overview of liver transplantation including indications, donor-recipient selection criteria, surgical procedures, and immunosuppressive therapies. A focus on infections in patients with chronic liver disease/cirrhosis and an overview of the specific infectious complications in liver transplant recipients are presented.

Endemic Mycoses in Solid Organ Transplant Recipients

The endemic mycoses are a group of thermally dimorphic fungal pathogens occupying a specific geographic range. In North America, the chief endemic mycoses are histoplasmosis, coccidioidomycosis, and blastomycosis. Endemic fungi can cause serious infections in solid organ transplant recipients from primary infection, reactivation of latent disease, or donor-derived infection.

Safety and efficacy of chronic suppressive azole therapy for endemic fungal infections in solid organ transplant recipients

BACKGROUND

Although the research is limited, treatment guidelines recommend lifelong suppressive azole therapy for disseminated endemic fungal infection (EFI) after solid organ transplantation (SOT). Suppressive azole therapy may prevent EFI recurrence at the risk of hepatotoxicity and drug interactions. We present real-world safety and effectiveness data of chronic suppressive azole therapy for EFI in SOT recipients over a 10-year period at a single comprehensive transplant center.

METHODS

A retrospective analysis was conducted of SOT recipients diagnosed with EFI from January 1, 2005, to May 1, 2015. Chronic suppressive azole therapy was defined as treatment for more than 12 months after diagnosis. Effectiveness of suppression was defined as preventing EFI reactivation. Safety endpoints included adverse reactions and drug interactions.

RESULTS

Over a 10-year period, 28 SOT recipients were diagnosed with EFI: 16 histoplasmosis, 9 blastomycosis, and 3 coccidioidomycosis. Eighteen (64%) patients were treated with chronic suppressive azole therapy for a median length of 36 months (range 15-90). One patient had an adverse drug interaction requiring azole discontinuation. There were no episodes of azole-related hepatotoxicity, toxicity from antirejection medication, or EFI reactivation.

CONCLUSIONS

Chronic suppressive azole therapy was safe and effective in preventing reactivation of EFI in SOT recipients.

Sepsis-like histoplasmosis in a kidney transplant patient

Histoplasmosis is a fungus infection that mainly affects immunosuppressed patients. The authors present a case of a kidney transplant recipient who developed sepsis-like histoplasmosis, na atypical but severe manifestation of the disease. The fungus was found in blood and in a skin biopsy, and the treatment with liposomal amphotericin resulted in hepatotoxicity.

Histoplasmosis in transplant recipients

Histoplasma capsulatum is a dimorphic fungus that most often causes asymptomatic infection in the immunocompetent population. In immunocompromised patients, including solid organ transplant (SOT) and hematopoietic cell transplant (HCT) recipients, however, it is likely to cause severe life-threatening infection. Post-transplant histoplasmosis (PTH) in SOT is uncommon with an incidence of ≤1% and is even rarer in HCT patients. The majority of PTH in SOT is diagnosed in the first 2 years following transplantation. Histoplasmosis may result from endogenous reactivation of latent infection, de novo post-transplant acquisition, and donor-derived infection. Disseminated infection is common. Fever is the most common symptom and clinical features are often nonspecific, but patients with disseminated infection may present with a septic picture. Other features, including pancytopenia and hepatosplenomegaly, may not be prominent early in the course of illness. Contemporary histoplasma antigen assays are the most sensitive tests but cross-reactivity with antigens of other fungi, including with Aspergillus galactomannan, is not uncommon. Treatment should be continued for at least a year. Histoplasma antigen levels have prognostic value and can be used to monitor the response to therapy. The attributable mortality is approximately 10%. Routine screening of donors and recipients is not currently recommended.

Clinical Manifestations and Treatment of Blastomycosis

The causal agents of blastomycosis, Blastomyces dermatitidis and Blastomyces gilchristii, belong to a group of thermally dimorphic fungi that can infect healthy and immunocompromised individuals. Following inhalation of mycelial fragments and spores into the lungs, Blastomyces spp convert into pathogenic yeast and evade host immune defenses to cause pneumonia and disseminated disease. The clinical spectrum of pulmonary blastomycosis is diverse. The diagnosis of blastomycosis requires a high degree of clinical suspicion and involves culture-based and non-culture-based fungal diagnostic tests. The site and severity of infection, and the presence of underlying immunosuppression or pregnancy, influence the selection of antifungal therapy.

Pulmonary histoplasmosis in a immunocompetent patient: A case report and literature review

In the present study, the case of a 54-year-old male patient diagnosed with pulmonary histoplasmosis is reported, with the aim to increase the understanding of the disease characteristics and thereby facilitate the diagnosis and treatment of pulmonary histoplasmosis. Clinical manifestations, diagnosis, treatment and clinical outcomes of the present case of pulmonary histoplasmosis were described. In addition, 76 histoplasmosis patients with complete clinical data were reviewed by searching the literature for relevant studies published during 1990 and 2015. The disease was mainly manifested as cough in the present case, while imaging examination detected a lump shadow in the right lung, accompanied by exudative lesions. Initially, the patient was suspected to have bacterial pneumonia, but subsequently the diagnosis of pulmonary histoplasmosis was confirmed by lung biopsy. The symptoms were alleviated following itraconazole treatment. The patient was physically stable and had no recurrence during the subsequent follow-up period. In conclusion, pulmonary histoplasmosis is characterized by non-specific clinical and imaging manifestations, and lung tissue biopsy or respiratory pathogen culture are regarded as the diagnostic gold standards. Individualized antifungal medication should be administered based upon the patients' situation in terms of dosage and duration.

Travel vaccination recommendations and endemic infection risks in solid organ transplantation recipients

BACKGROUND

Solid organ transplant (SOT) recipients are often heavily immunosuppressed and consequently at risk of serious illness from vaccine preventable viral and bacterial infections or with endemic fungal and parasitic infections. We review the literature to provide guidance regarding the timing and appropriateness of vaccination and pathogen avoidance related to the immunological status of SOT recipients.

METHODS

A PUBMED search ([Vaccination OR vaccine] AND/OR ["specific vaccine"] AND/OR [immunology OR immune response OR cytokine OR T lymphocyte] AND transplant was performed. A review of the literature was performed in order to develop recommendations on vaccination for SOT recipients travelling to high-risk destinations.

RESULTS

Whilst immunological failure of vaccination in SOT is primarily the result of impaired B-cell responses, the role of T-cells in vaccine failure and success remains unknown. Vaccination should be initiated at least 4 weeks prior to SOT or more than 6 months post-SOT. Avoidance of live vaccination is generally recommended, although some live vaccines may be considered in the specific situations (e.g. yellow fever). The practicing physician requires a detailed understanding of region-specific endemic pathogen risks.

CONCLUSIONS

We provide a vaccination and endemic pathogen guide for physicians and travel clinics involved in the care of SOT recipients. In addition, recommendations based on timing of anticipated immunological recovery and available evidence regarding vaccine immunogenicity in SOT recipients are provided to help guide pre-travel consultations.

Blastomycosis

Blastomycosis is an endemic fungal infection due to Blastomyces dermatitidis that most commonly causes pneumonia; but the organism can disseminate to any organ system, most commonly the skin, bones/joints, and genitourinary tract. Both immunocompetent and immunocompromised persons can be infected, but more severe disease occurs in the immunocompromised. Blastomycosis can be diagnosed by culture, direct visualization of the yeast in affected tissue, and/or antigen testing. Treatment course and duration depend on severity of illness. For mild to moderate pulmonary disease the treatment is itraconazole. For severe blastomycosis, lipid formulation amphotericin B is given, followed by step-down therapy with itraconazole.

Approach to the Solid Organ Transplant Patient with Suspected Fungal Infection

In solid organ transplant (SOT) recipients, invasive fungal infections (IFIs) are associated with significant morbidity and mortality. Detection of IFIs can be difficult because the signs and symptoms are similar to those of viral or bacterial infections, and diagnostic techniques have limited sensitivity and specificity. Clinicians must rely on knowledge of the patient's risk factors for fungal infection to make a diagnosis. The authors describe their approach to the SOT recipient with suspected fungal infection. The epidemiology of IFIs in the SOT population is reviewed, and a syndromic approach to suspected IFI in SOT recipients is described.

In Search for Equilibrium: Immunosuppression Versus Opportunistic Infection

Post-transplant immunosuppression is necessary to prevent organ rejection. Immunosuppression itself can introduce complications arising from opportunistic infections. We present a case of disseminated blastomycosis manifested only as a skin lesion in an asymptomatic patient post-orthotopic heart transplantation. A 64-year-old female who had recently undergone orthotopic heart transplant for end-stage ischemic cardiomyopathy presented for a scheduled routine cardiac biopsy. The patient had no current complaints other than a crusted plaque noticed at her nasal tip. It initially manifested 6 months after surgery as a pimple that she repeatedly tried to manipulate resulting in redness and crust formation. Her immunosuppressive and prophylactic medications included: mycophenolate, tacrolimus, prednisone, bactrim, acyclovir, valganciclovir, pyrimethamine/sulfadiazine, and fluconazole. On physical examination, she was flushed, with a large and exquisitely tender crusted necrotic lesion involving almost the entire half of the nose anteriorly, the left forehead and right side of the neck. She had decreased air entry over the right lung field as well. A computed tomography (CT) image of the chest was ordered to investigate this concerning physical exam finding in the post-transplant state of this patient on immunosuppressive therapy. Chest CT revealed bilateral nodular pulmonary infiltrates with confluence in the posterior right upper lobe. Blood cultures for aerobic and anerobic organisms were negative. Both excisional biopsy of the nasal cutaneous ulcer and bronchial biopsy demonstrated numerous fungal yeast forms morphologically consistent with Blastomyces. Cultures of both specimens grew Blastomyces dermatitidis, with methicillin-resistant Staphylococcus aureus (MRSA) superinfection of the nose. She received 14 days of intravenous (IV) amphotericin B for disseminated blastomycosis and 7 days of IV vancomycin for MRSA. Her symptoms and cutaneous lesions improved and she received maintenance itraconazole treatment for 1 year. This case illustrates a delicate balance that must be struck between suppressing the immune response to prevent graft rejection and avoiding over-immunosuppression that can lead to susceptibility to infection. Thus, in any post-transplant patient, a vigorous history and physical must be performed given that infections may present without symptoms and cause grave consequences.

An Approach to a Pulmonary Infiltrate in Solid Organ Transplant Recipients

The onset of a pulmonary infiltrate in a solid organ transplant (SOT) recipient is both a challenging diagnostic and therapeutic challenge. We outline the potential aetiologies of a pulmonary infiltrate in a SOT recipient, with particular attention paid to fungal pathogens. A diagnostic and empirical therapy approach to a pulmonary infiltrate, especially invasive fungal disease (IFD) in SOT recipients, is provided.