Histoplasmosis-associated cross-reactivity in the BioRad Platelia Aspergillus enzyme immunoassay

Histoplasma capsulatum as a cause for prolonged pulmonary illness in an immunocompetent returning traveller from Bangladesh

Fungal infections can be challenging to diagnose in returning travellers due to their non-specific clinical manifestations and changing epidemiology. We present a case of progressive disseminated histoplasmosis in a returning traveller from Bangladesh. The patient had a progressive and prolonged respiratory illness necessitating mechanical ventilatory support. The clue to potential fungal aetiology was provided by serum fungal markers - 1-3-β-D-glucan and Aspergillus galactomannan. Diagnosis was eventually made using panfungal PCR on bronchioalveolar lavage fluid.

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.

Histoplasma antigen detection in unconfirmed pulmonary tuberculosis and cross-reactivity with Aspergillus antigen in patients and in food in Jakarta, Indonesia

PURPOSE

H. capsulatum is endemic in Indonesia, but the value of Histoplasma antigen detection has not been studied.

PATIENTS AND METHODS

Histoplasma galactomannan (GM) ELISA was applied to sera of patients with unproven pulmonary tuberculosis (TB) and patients with a positive Aspergillus GM. Both Histoplasma and Aspergillus GM tests were performed to determine any possible cross-reaction with certain foods.

RESULTS

Fourteen of 122 (11.5%) sera of patients with newly diagnosed clinical TB were positive for Histoplasma GM. The positivity rate in the serum of patients 5-6 and 12 months after TB diagnosis was 3.8% and 3.5%, respectively. Of 88 positive Aspergillus GM sera, 63 (71.6%) were also positive for Histoplasma GM. All tested foods were positive for Aspergillus GM, while 65% of foods were positive for Histoplasma GM.

CONCLUSION

Galactomannan is widespread in sera and food in Jakarta, possibly related to food consumption. Histoplasma and Aspergillus antigen detection for the diagnosis will require additional means of confirming the diagnosis; negative tests may be more helpful for ruling out invasive histoplasmosis and aspergillosis.

Native mitral valve fungal endocarditis caused by Aspergillus fumigatus: A case report

INTRODUCTION

Aspergillus endocarditis is a rare fungal infection associated with a poor prognosis. Most cases of Aspergillus endocarditis involve prosthetic valves, with native valve involvement being rarely reported.

CASE PRESENTATION

A 53-year-old asian female patient presented with fever, chills, dyspnea, generalized fatigue, and significant weight loss one month after undergoing left lower lobectomy for a pulmonary abscess. Echocardiogram showed a large mobile vegetation with a broad base on the anterior leaflet of the mitral valve, resembling atrial myxoma. Despite negative blood cultures, circulating DNA of Aspergillus fumigatus was detected by metagenome Next Generation Sequencing, prompting the initiation of empiric antifungal therapy with voriconazole. Emergency surgery, involving thorough debridement and mitral valve replacement, was successfully performed. Indefinite fungal suppression therapy with oral voriconazole is continued to mitigate the risk of recurrence. The patient survived with no signs of Aspergillus disease recurrence for four years.

CLINICAL DISCUSSION

Diagnosis of Aspergillus endocarditis requires a high index of suspicion and is often delayed due to consistently negative results from blood cultures. Non-culture-based methods, particularly metagenome Next-Generation Sequencing, play a crucial role in early diagnosis and therapeutic decision-making. Surgical debridement and valve replacement are imperative for survival in cases of Aspergillus endocarditis. Voriconazole should be considered the primary fungicidal agent for its treatment. Moreover, lifelong fungal suppression therapy is strongly recommended for all survivors to ensure long-term survival and minimize the risk of recurrence.

CONCLUSION

Despite grim prognosis associated with Aspergillus endocarditis, patients can attain long-term survival through meticulous surgical debridement and lifelong antifungal therapy.

Identification and production of novel potential pathogen-specific biomarkers for diagnosis of histoplasmosis

IMPORTANCE

Histoplasmosis is considered one of the most important mycoses due to the increasing number of individuals susceptible to develop severe clinical forms, particularly those with HIV/AIDS or receiving immunosuppressive biological therapies, the high mortality rates reported when antifungal treatment is not initiated in a timely manner, and the limitations of conventional diagnostic methods. In this context, there is a clear need to improve the capacity of diagnostic tools to specifically detect the fungal pathogen, regardless of the patient's clinical condition or the presence of other co-infections. The proposed novel pathogen-specific biomarkers have the potential to be used in immunodiagnostic platforms and antifungal treatment monitoring in histoplasmosis. In addition, the bioinformatics strategy used in this study could be applied to identify potential diagnostic biomarkers in other models of fungal infection of public health importance.

A review of endemic mycoses after hematopoietic stem cell transplantation

BACKGROUND

Endemic mycoses after hematopoietic stem cell transplantation (HSCT) are rarely reported. We aimed to comprehensively review the clinical presentation and outcomes of endemic mycoses in this immunocompromised population.

METHODS

Multiple databases were reviewed from inception through May 31, 2023 using endemic fungi as keywords (e.g., coccidioides, histoplasma, blastomyces, talaromyces, and paracoccidioides). Only hematopoietic transplants were included.

RESULTS

There were 16 publications on endemic mycoses after HSCT that reported nine unique cases of histoplasmosis, seven coccidioidomycosis, and two talaromycosis. No cases of paracoccidioides and blastomycoses were identified. Fifteen cases were allogeneic hematopoietic transplant recipients and three were autologous. Many were male (14/18, 77.8%) and overall median age was 50 (range 21-75) years. Among the 16 patients with coccidiodomycosis or histoplasmosis, fever, cytopenias and disseminated disease were the most common clinical presentations, with median onset of 8 or 12 months after HSCT, respectively. Likewise, the two HSCT patients with talaromycosis presented with disseminated disease at 12 and 48 months after transplantation. The vast majority were not on effective azole prophylaxis at the time of presentation, and many had recent intensification of immunosuppression. Nine of 18 patients died (50%), and all deaths occurred among patients with disseminated endemic mycoses.

CONCLUSION

Endemic mycoses among HSCT are uncommon. Onset was late, after discontinuation of azole prophylaxis, or was associated with intensification of immunosuppression. Disseminated disease was a common presentation, manifested by fever and cytopenias. Attributable mortality was high, and emphasizes the need for a high index of clinical suspicion so that prompt diagnosis and treatment is provided.

Invasive fungal infections in liver diseases

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

A difficult-to-treat pleuropulmonary histoplasmosis in a patient with rheumatoid arthritis in Taiwan

Amphotericin B and itraconazole are the primary agents for treating histoplasmosis. Newer azoles are alternatives for patients refractory to or intolerant of standard therapy. We report an 83-year-old woman with rheumatoid arthritis complicated with pleuropulmonary histoplasmosis who responded to liposomal amphotericin B, but progressed under voriconazole and posaconazole maintenance therapy.

Updates on Histoplasmosis in Solid Organ Transplantation

Purpose of Review

Recent Findings

Summary

Serum galactomannan in histoplasmosis in HIV

Histoplasmosis is an opportunistic infection (OI) in HIV infected patients. The Diagnosis is challenging due to lack of testing facilities. Hereby we report a young male who presented with fever & rash, was diagnosed with HIV and disseminated histoplasmosis. The timely management with antifungals was started after the of positive serum galactomannan report in the background of appropriate clinical setting.

Challenges in Serologic Diagnostics of Neglected Human Systemic Mycoses: An Overview on Characterization of New Targets

Systemic mycoses have been viewed as neglected diseases and they are responsible for deaths and disabilities around the world. Rapid, low-cost, simple, highly-specific and sensitive diagnostic tests are critical components of patient care, disease control and active surveillance. However, the diagnosis of fungal infections represents a great challenge because of the decline in the expertise needed for identifying fungi, and a reduced number of instruments and assays specific to fungal identification. Unfortunately, time of diagnosis is one of the most important risk factors for mortality rates from many of the systemic mycoses. In addition, phenotypic and biochemical identification methods are often time-consuming, which has created an increasing demand for new methods of fungal identification. In this review, we discuss the current context of the diagnosis of the main systemic mycoses and propose alternative approaches for the identification of new targets for fungal pathogens, which can help in the development of new diagnostic tests.

Aspergillus fumigatus and aspergillosis: From basics to clinics

The airborne fungus Aspergillus fumigatus poses a serious health threat to humans by causing numerous invasive infections and a notable mortality in humans, especially in immunocompromised patients. Mould-active azoles are the frontline therapeutics employed to treat aspergillosis. The global emergence of azole-resistant A. fumigatus isolates in clinic and environment, however, notoriously limits the therapeutic options of mould-active antifungals and potentially can be attributed to a mortality rate reaching up to 100 %. Although specific mutations in CYP 51A are the main cause of azole resistance, there is a new wave of azole-resistant isolates with wild-type CYP 51A genotype challenging the efficacy of the current diagnostic tools. Therefore, applications of whole-genome sequencing are increasingly gaining popularity to overcome such challenges. Prominent echinocandin tolerance, as well as liver and kidney toxicity posed by amphotericin B, necessitate a continuous quest for novel antifungal drugs to combat emerging azole-resistant A. fumigatus isolates. Animal models and the tools used for genetic engineering require further refinement to facilitate a better understanding about the resistance mechanisms, virulence, and immune reactions orchestrated against A. fumigatus. This review paper comprehensively discusses the current clinical challenges caused by A. fumigatus and provides insights on how to address them.

Histoplasmosis Diagnosed in Europe and Israel: A Case Report and Systematic Review of the Literature from 2005 to 2020

Human histoplasmosis is a mycosis caused by two distinct varieties of a dimorphic fungus: Histoplasma capsulatum var. capsulatum and H. capsulatum var. duboisii. In Europe, it is usually imported by migrants and travellers, although there have been some autochthonous cases, especially in Italy; however, most European physicians are unfamiliar with its clinical and pathological picture, particularly among immunocompromised patients without HIV infection. This systematic review of all the cases of histoplasmosis reported in Europe and Israel between 2005 and 2020 identified 728 cases diagnosed in 17 European countries and Israel described in 133 articles. The vast majority were imported (mainly from Central and South America), but there were also seven autochthonous cases (six in Europe and one in Israel). The patients were prevalently males (60.4%), and their ages ranged from 2 to 86 years. The time between leaving an endemic region and the diagnosis of histoplasmosis varied from a few weeks to more than 40 years. Progressive disseminated histoplasmosis was the most frequent clinical picture among people living with HIV infection (89.5%) or a different immunocompromising condition (57.1%), but it was also recorded in 6.2% of immunocompetent patients. Twenty-eight cases were caused by Histoplasma duboisii. Immunocompromised patients without HIV infection had the worst outcomes, with a mortality rate of 32%.

Post kidney transplant histoplasmosis: An under-recognized diagnosis in India

Histoplasmosis is an invasive mycosis caused by fungus Histoplasma capsulatum. Clinical features of histoplasmosis are often nonspecific, but patients with disseminated infection may present with severe manifestations posing an increasing threat to patients with various immunocompromised conditions. It is often misdiagnosed as tuberculosis in endemic regions leading to high mortality. There is under-reporting of histoplasmosis in solid organ transplant from India undermining its actual incidence and impact. As a result of the potentially fatal nature of the disease, careful evaluation with tissue diagnosis is recommended. We present a series of five cases of disseminated histoplasmosis in renal transplant recipients from our centre, highlighting its significance as differential diagnosis in this population. To our knowledge, this is the largest case series reported from India in renal transplant patients.

Management of fever and neutropenia in the adult patient with acute myeloid leukemia

INTRODUCTION

Febrile neutropenia represents one of the most common treatment-associated complications in the management of acute myeloid leukemia (AML) and is considered an oncologic emergency. Rapid and detailed workup as well as the initiation of empiric broad-spectrum antibiotic therapy are critical to avoid sepsis and to reduce mortality. Although a definitive source of infection is frequently not identified, the severely immunosuppressed status of the AML patient undergoing cytotoxic therapy results in a high risk for a wide array of bacterial, fungal, and viral etiologies.

AREAS COVERED

The authors herein review the diagnostic and therapeutic approach to the neutropenic leukemia patient based on the current knowledge. Special consideration is given to the rapidly changing therapeutic landscape in AML, creating new challenges in the management of infectious complications.

EXPERT OPINION

Multidrug-resistant organisms pose a major challenge in the management of neutropenic fever patients with hematologic malignancies - including AML. Future directions to improve outcomes demand innovative treatment approaches as well as advances in biomarker research to facilitate diagnosis and disease monitoring. Recent achievements in AML-targeted therapy led to an increased incidence of differentiation syndrome, a potentially life-threatening side effect that frequently resembles clinical infection and requires prompt recognition and aggressive intervention.

Work-up for Fever During Neutropenia for Both the Stem Cell Transplant Recipient and the Hematologic Malignancy Patient

Fever is a common complication in patients with underlying neutropenia and is associated with significant mortality in neutropenic patients with acute myelogenous leukemia or hematopoietic cell transplant. Fever may be the only sign of infection and requires further clinical assessment, including a history, a physical examination, and additional laboratory and radiographic testing. National and international guidelines recommend initiation of empiric antimicrobial therapy in patients with fever during neutropenia. Stepwise escalation of antibacterial therapy, followed by antifungal therapy for patients with persistent fever, generally is recommended. Consideration should also be given to de-escalation of antimicrobial therapy in the appropriate clinical settings.

Diagnostic laboratory immunology for talaromycosis (penicilliosis): review from the bench-top techniques to the point-of-care testing

The pathogenic fungus Talaromyces (formerly Penicillium) marneffei is a thermally dimorphic fungus that can cause disseminated infection in patients with secondary immunodeficiency syndrome, in particular in the setting of advanced HIV infection. The areas of highest incidence are in Southeast Asia, Southern China, and Indian subcontinents. Talaromycosis (formerly penicilliosis) is identified as an AIDS-defining illness, and it has recently been recognized in non-HIV-associated patients with impaired cellular-mediated immunity. Microbiological culture is the gold standard method for the diagnosis of T. marneffei infection and usually requires up to 2-4 weeks for detectable growth to occur, which may result in a delay of appropriate treatment. Immunodiagnosis has become an alternative method for confirming talaromycosis. This article reviews various immunological tests for the diagnosis of talaromycosis, including a proposed novel rapid point-of-care assay using a new T. marneffei yeast phase-specific monoclonal antibody.

Diagnosis of invasive fungal disease in children: a narrative review

Introduction: Invasive fungal diseases (IFD) represent important causes of morbidity and mortality in pediatrics. Early diagnosis and treatment of IFD is associated with better outcome and this entails the need to use fast and highly sensitive and specific methods that can support clinicians in the management of IFD.Areas covered: A narrative review was performed on conventional diagnostic methods such as culture, microscopy and histopathology are still gold standard but are burdened by a lack of sensitivity and specificity; on the other hand, imaging and noninvasive antigen-based such as beta-D-glucan, galactomannan and molecular biomarkers are the most convenient nonculture methods for diagnosis and monitoring effects of therapy. Aim of the present review is to summarize what is available in these fields at end of the second decade of the third millennium and look for future perspectives.Expert opinion: Promising and useful diagnostic methods have been applied in infectious disease diagnosis in clinical practice or in designing platforms. Unfortunately, most of them are not standardized or validated in pediatric population. However, clinicians should be aware of all innovative diagnostic tools to use in combination with conventional diagnostic methods for a better management of pathology and patient.

Urine Antigen Detection as an Aid to Diagnose Invasive Aspergillosis

Background

Establishing rapid diagnoses of invasive aspergillosis (IA) is a priority tests that detect galactomannan and β-d-glucan are available, but are technically cumbersome and rely on invasive sampling (blood or bronchoalveolar lavage).

Methods

We optimized a lateral flow dipstick assay using the galactofuranose-specific monoclonal antibody (mAb476), which recognizes urine antigens after Aspergillus fumigatus pulmonary infection in animals. Urine samples were obtained from a cohort of 78 subjects undergoing evaluation for suspected invasive fungal infections, and stored frozen until testing. Urine was processed by centrifugation through desalting columns and exposed to dipsticks. Reviewers blinded to clinical diagnoses graded results. Western blots were performed on urine samples from 2 subjects to characterize mAb476-reactive antigens.

Results

Per-patient sensitivity and specificity for diagnosis of proven or probable IA in the overall cohort was 80% (95% confidence interval [CI], 61.4%-92.3%) and 92% (95% CI, 74%-99%), respectively. In the subgroup with cancer, sensitivity was 89.5% (95% CI, 66.7%-98.7%) and specificity was 90.9% (95% CI, 58.7%-99.8%); among all others, sensitivity and specificity were 63.6% (95% CI, 30.8%-89.1%) and 92.9% (95% CI, 66.1%-99.8%), respectively. Eliminating lung transplant recipients with airway disease increased sensitivity in the noncancer cohort (85.7% [95% CI, 42.1%-99.6%]). Semiquantitative urine assay results correlated with serum galactomannan indices. Western blots demonstrated mAb476-reactive antigens in urine from cases, ranging between 26 kDa and 35 kDa in size.

Conclusions

Urine testing using mAb476 may be used as an aid to diagnose IA in high-risk patients.

Disseminated blastomycosis in coalworkers' pneumoconiosis

Blastomyces dermatitidis is a thermally dimorphic fungus that can cause pulmonary, extrapulmonary, or disseminated infections. Though it can infect both immune-competent and immunocompromised hosts, the disease can be severe in immunocompromised hosts. Exposure to silica dust is associated with silicosis, and this is associated with impaired immunity and an increased risk of mycobacterial and fungal infections. The fungal infections commonly associated with pneumoconiosis are pulmonary aspergillosis, histoplasmosis, coccidioidomycosis, and cryptococcosis. However, there is a dearth of data on the association of pneumoconiosis and blastomycosis. Clinical deterioration and new cavitary lesions in patients with pneumoconiosis should alert clinicians of new pulmonary infection. Traditional sputum sampling may lead to poor diagnostic yield, because the organism is frequently surrounded by a fibrotic wall. Aggressive diagnostic testing with lung or skin biopsies may be warranted. We present the first reported case of disseminated blastomycosis in a patient with coalworkers' pneumoconiosis.

Peripheral blood smear findings in a kidney transplant recipient with disseminated histoplasmosis and elevated Aspergillus galactomannan

We report a case of disseminated histoplasmosis in a renal transplant recipient who presented with a nodular pulmonary lesion and elevated serum and bronchoalveolar lavage (BAL) Aspergillus galatomannan. This almost led to an erroneous diagnosis of invasive aspergillosis since the donor respiratory tract was known to be colonized with Aspergillus terreus. However, distinctive intracelluar Histoplasma yeasts on peripheral blood smear led to early diagnosis and appropriate treatment. The cross-reactivity between Aspergillus galactomannan and Histoplasma antigen is discussed further.

Galactomannan detection in broncho-alveolar lavage fluid for invasive aspergillosis in immunocompromised patients

BACKGROUND

Invasive aspergillosis (IA) is a life-threatening opportunistic mycosis that occurs in some people with a compromised immune system. The serum galactomannan enzyme-linked immunosorbent assay (ELISA) rapidly gained widespread acceptance as part of the diagnostic work-up of a patient suspected of IA. Due to its non-invasive nature, it can be used as a routine screening test. The ELISA can also be performed on bronchoalveolar lavage (BAL), allowing sampling of the immediate vicinity of the infection. The invasive nature of acquiring BAL, however, changes the role of the galactomannan test significantly, for example by precluding its use as a routine screening test.

OBJECTIVES

To assess the diagnostic accuracy of galactomannan detection in BAL for the diagnosis of IA in people who are immunocompromised, at different cut-off values for test positivity, in accordance with the Cochrane Diagnostic Test Accuracy Handbook.

SEARCH METHODS

We searched three bibliographic databases including MEDLINE on 9 September 2016 for aspergillosis and galactomannan as text words and subject headings where appropriate. We checked reference lists of included studies for additional studies.

SELECTION CRITERIA

We included cohort studies that examined the accuracy of BAL galactomannan for the diagnosis of IA in immunocompromised patients if they used the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG) classification as reference standard.

DATA COLLECTION AND ANALYSIS

Two review authors assessed study quality and extracted data. Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) was used for quality assessment.

MAIN RESULTS

We included 17 studies in our review. All studies except one had a high risk of bias in two or more domains. The diagnostic performance of an optical density index (ODI) of 0.5 as cut-off value was reported in 12 studies (with 1123 patients). The estimated sensitivity was 0.88 (95% confidence interval (CI) 0.75 to 1.00) and specificity 0.81 (95% CI 0.71 to 0.91). The performance of an ODI of 1.0 as cut-off value could be determined in 11 studies (with 648 patients). The sensitivity was 0.78 (95% CI 0.61 to 0.95) and specificity 0.93 (95% CI 0.87 to 0.98). At a cut-off ODI of 1.5 or higher, the heterogeneity in specificity decreased significantly and was invariably >90%.

AUTHORS' CONCLUSIONS

The optimal cut-off value depends on the local incidence and clinical pathway. At a prevalence of 12% a hypothetical population of 1000 patients will consist of 120 patients with IA. At a cut-off value of 0.5 14 patients with IA will be missed and there will be 167 patients incorrectly diagnosed with IA. If we use the test at a cut-off value of 1.0, we will miss 26 patients with IA. And there will be 62 patients incorrectly diagnosed with invasive aspergillosis. The populations and results were very heterogeneous. Therefore, interpretation and extrapolation of these results has to be performed with caution. A test result of 1.5 ODI or higher appears a strong indicator of IA.

Urine Antigen Detection as an Aid to Diagnose Invasive Aspergillosis

Background

Establishing rapid diagnoses of invasive aspergillosis (IA) is a priority tests that detect galactomannan and β-d-glucan are available, but are technically cumbersome and rely on invasive sampling (blood or bronchoalveolar lavage).

Methods

We optimized a lateral flow dipstick assay using the galactofuranose-specific monoclonal antibody (mAb476), which recognizes urine antigens after Aspergillus fumigatus pulmonary infection in animals. Urine samples were obtained from a cohort of 78 subjects undergoing evaluation for suspected invasive fungal infections, and stored frozen until testing. Urine was processed by centrifugation through desalting columns and exposed to dipsticks. Reviewers blinded to clinical diagnoses graded results. Western blots were performed on urine samples from 2 subjects to characterize mAb476-reactive antigens.

Results

Per-patient sensitivity and specificity for diagnosis of proven or probable IA in the overall cohort was 80% (95% confidence interval [CI], 61.4%-92.3%) and 92% (95% CI, 74%-99%), respectively. In the subgroup with cancer, sensitivity was 89.5% (95% CI, 66.7%-98.7%) and specificity was 90.9% (95% CI, 58.7%-99.8%); among all others, sensitivity and specificity were 63.6% (95% CI, 30.8%-89.1%) and 92.9% (95% CI, 66.1%-99.8%), respectively. Eliminating lung transplant recipients with airway disease increased sensitivity in the noncancer cohort (85.7% [95% CI, 42.1%-99.6%]). Semiquantitative urine assay results correlated with serum galactomannan indices. Western blots demonstrated mAb476-reactive antigens in urine from cases, ranging between 26 kDa and 35 kDa in size.

Conclusions

Urine testing using mAb476 may be used as an aid to diagnose IA in high-risk patients.

Early-Onset Invasive Infection Due to Corynespora cassiicola Associated with Compound Heterozygous CARD9 Mutations in a Colombian Patient

PURPOSE

CARD9 deficiency is an inborn error of immunity that predisposes otherwise healthy humans to mucocutaneous and invasive fungal infections, mostly caused by Candida, but also by dermatophytes, Aspergillus, and other fungi. Phaeohyphomycosis are an emerging group of fungal infections caused by dematiaceous fungi (phaeohyphomycetes) and are being increasingly identified in patients with CARD9 deficiency. The Corynespora genus belongs to phaeohyphomycetes and only one adult patient with CARD9 deficiency has been reported to suffer from invasive disease caused by C. cassiicola. We identified a Colombian child with an early-onset, deep, and destructive mucocutaneous infection due to C. cassiicola and we searched for mutations in CARD9.

METHODS

We reviewed the medical records and immunological findings in the patient. Microbiologic tests and biopsies were performed. Whole-exome sequencing (WES) was made and Sanger sequencing was used to confirm the CARD9 mutations in the patient and her family. Finally, CARD9 protein expression was evaluated in peripheral blood mononuclear cells (PBMC) by western blotting.

RESULTS

The patient was affected by a large, indurated, foul-smelling, and verrucous ulcerated lesion on the left side of the face with extensive necrosis and crusting, due to a C. cassiicola infectious disease. WES led to the identification of compound heterozygous mutations in the patient consisting of the previously reported p.Q289* nonsense (c.865C > T, exon 6) mutation, and a novel deletion (c.23_29del; p.Asp8Alafs10*) leading to a frameshift and a premature stop codon in exon 2. CARD9 protein expression was absent in peripheral blood mononuclear cells from the patient.

CONCLUSION

We describe here compound heterozygous loss-of-expression mutations in CARD9 leading to severe deep and destructive mucocutaneous phaeohyphomycosis due to C. cassiicola in a Colombian child.

Histoplasmosis in non-endemic North-Western part of India

Purpose of Study

The western and North-Western parts of India are usually considered non-endemic for histoplasmosis. On the contrary, we observe histoplasmosis cases with relatively higher frequency from this region although the awareness and laboratory facility to diagnose the disease are not adequate. Hence, we planned the present retrospective study to compile the cases and to analyse different clinical parameters.

Materials and Methods

Medical records of the patients diagnosed with histoplasmosis during January 2012-August 2017 at two infectious disease clinics of Ahmedabad were included in this study.

Results

During the study, 12 cases of histoplasmosis were diagnosed. The median age of the patients was 53 years; all males except one. The diagnosis of histoplasmosis was confirmed on histopathology for 11 cases, and one patient was diagnosed as probable histoplasmosis. The patients were either from Gujarat or Rajasthan without any travel history to endemic zone of histoplasmosis, except one patient. The majority (67%) of the patients had no apparent immunosuppression. Adrenal enlargement, oral ulcers and lymphadenopathy were common presentations in four patients each. We lost two patients in follow-up, and rest 10 patients responded to either to amphotericin B deoxycholate and/or itraconazole therapy.

Conclusion

This study highlights that Gujarat and Rajasthan are an endemic region for histoplasmosis, and a systematic study is required to understand epidemiology of the disease. Histoplasmosis should be a differential diagnosis in a patient presenting with adrenal enlargement, lymphadenopathy, oral ulcers and fever of unknown origin in this region.

The performance of galactomannan in combination with 1,3-β-D-glucan or aspergillus-lateral flow device for the diagnosis of invasive aspergillosis: Evidences from 13 studies

Galactomannan (GM), 1,3-β-D-glucan (BDG) and aspergillus-lateral flow device (LFD) are recognized as diagnostic tools for invasive aspergillosis (IA). The combined performance of these assays, however, is inconsistent in various studies. We undertook a meta-analysis of 13 studies involving 1513 patients to evaluate the utility of GM in combination with BDG or LFD for diagnosing IA. The pooled SEN, SPE, PLR, NLR and diagnostic odds ratio (DOR) were calculated and constructed to summarize the overall combined performance. Combining both positive results of GM and BDG assays leaded to the pooled SEN 0.49 (95%CI 0.27-0.72), SPE 0.98 (95%CI 0.94-1.00), PLR 31.68 (95%CI 5.36-187.37), NLR 0.52 (95%CI 0.32-0.84) and DOR 61.23 (95%CI 6.96-538.90). Comparing with GM and BDG assays, both positive results of GM and LFD leaded to high SEN, similar SPE, low PLR and NLR. At least one positive result of GM or LFD conferred great SEN 0.93 and low NLR 0.08. Both positive results of GM and BDG or LFD assay were in favor of confirming the existence of IA. And both negative results of GM and LFD were beneficial to rule out IA. Further studies with sufficient sample size should focus on the diagnostic performance and cost-effectiveness of these combined tests in clinical setting.

Angioinvasive fungal infections impacting the skin: Diagnosis, management, and complications

As discussed in the first article in this continuing medical education series, angioinvasive fungal infections pose a significant risk to immunocompromised and immunocompetent patients alike, with a potential for severe morbidity and high mortality. The first article in this series focused on the epidemiology and clinical presentation of these infections; this article discusses the diagnosis, management, and potential complications of these infections. The mainstay diagnostic tests (positive tissue culture with histologic confirmation) are often supplemented with serum biomarker assays and molecular testing (eg, quantitative polymerase chain reaction analysis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry) to ensure proper speciation. When an angioinvasive fungal infection is suspected or diagnosed, further workup for visceral involvement also is essential and may partially depend on the organism. Different fungal organisms have varied susceptibilities to antifungal agents, and knowledge on optimal treatment regimens is important to avoid the potential complications associated with undertreated or untreated fungal infections.

Novel mouse monoclonal antibodies specifically recognize Aspergillus fumigatus galactomannan

A panel of specific monoclonal antibodies (mAbs) against synthetic pentasaccharide β-D-Galf-(1→5)-[β-D-Galf-(1→5)]₃-α-D-Manp, structurally related to Aspergillus fumigatus galactomannan, was generated using mice immunized with synthetic pentasaccharide-BSA conjugate and by hybridoma technology. Two selected mAbs, 7B8 and 8G4, could bind with the initial pentasaccharide with affinity constants of approximately 5.3 nM and 6.4 nM, respectively, based on surface plasmon resonance-based biosensor assay. The glycoarray, built from a series of synthetic oligosaccharide derivatives representing different galactomannan fragments, demonstrated that mAb 8G4 could effectively recognize the parental pentasaccharide while mAb 7B8 recognizes its constituting trisaccharide parts. Immunofluorescence studies showed that both 7B8 and 8G4 could stain A. fumigatus cells in culture efficiently, but not the mutant strain lacking galactomannan. In addition, confocal microscopy demonstrated that Candida albicans, Bifidobacterium longum, Lactobacillus plantarum, and numerous gram-positive and gram-negative bacteria were not labeled by mAbs 7B8 and 8G4. The generated mAbs can be considered promising for the development of a new specific enzyme-linked assay for detection of A. fumigatus, which is highly demanded for medical and environmental controls.

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.

High Mortality and Coinfection in a Prospective Cohort of Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome Patients with Histoplasmosis in Guatemala

Histoplasmosis is one of the most common and deadly opportunistic infections among persons living with human immunodeficiency virus (HIV)/acquired immune deficiency syndrome in Latin America, but due to limited diagnostic capacity in this region, few data on the burden and clinical characteristics of this disease exist. Between 2005 and 2009, we enrolled patients ≥ 18 years of age with suspected histoplasmosis at a hospital-based HIV clinic in Guatemala City. A case of suspected histoplasmosis was defined as a person presenting with at least three of five clinical or radiologic criteria. A confirmed case of histoplasmosis was defined as a person with a positive culture or urine antigen test for Histoplasma capsulatum. Demographic and clinical data were also collected and analyzed. Of 263 enrolled as suspected cases of histoplasmosis, 101 (38.4%) were confirmed cases. Median time to diagnosis was 15 days after presentation (interquartile range [IQR] = 5-23). Crude overall mortality was 43.6%; median survival time was 19 days (IQR = 4-69). Mycobacterial infection was diagnosed in 70 (26.6%) cases; 26 (25.7%) histoplasmosis cases were coinfected with mycobacteria. High mortality and short survival time after initial symptoms were observed in patients with histoplasmosis. Mycobacterial coinfection diagnoses were frequent, highlighting the importance of pursuing diagnoses for both diseases.

Progressive Dispersion of Azole Resistance in Aspergillus fumigatus: Fatal Invasive Aspergillosis in a Patient with Acute Myeloid Leukemia Infected with an A. fumigatus Strain with a cyp51A TR46 Y121F M172I T289A Allele

Patients with hematologic malignancies as well as allogeneic hematopoietic stem cell transplantation (HSCT) patients are at high risk for invasive aspergillosis. Here, we report a culture- and autopsy-proven fatal invasive aspergillosis in an allogeneic HSTC patient which he developed despite posaconazole prophylaxis. The agent was determined to be an azole-resistant Aspergillus fumigatus strain bearing the cyp51A mutation combination TR₄₆ Y121F M172I T289A. At increasing frequency, the azole resistance of A. fumigatus is being reported globally, limiting treatment options and complicating regimens.

Early diagnosis of invasive mould infections and disease

Invasive mould infections (IMIs), such as invasive aspergillosis or mucormycosis, are a major cause of death in patients with haematological cancer and in patients receiving long-term immunosuppressive therapy. Early diagnosis and prompt initiation of antifungal therapy are crucial steps in the management of patients with IMI. The diagnosis of IMI remains a major challenge, with an increased spectrum of fungal pathogens and a diversity of clinical and radiological presentations within the expanding spectrum of immunocompromised hosts. Diagnosis is difficult to establish and is expressed on a scale of probability (proven, probable and possible). Imaging (CT scan), microbiological tools (direct examination, culture, PCR, fungal biomarkers) and histopathology are the pillars of the diagnostic work-up of IMI. None of the currently available diagnostic tests provides sufficient sensitivity and specificity alone, so the optimal approach relies on a combination of multiple diagnostic strategies, including imaging, fungal biomarkers (galactomannan and 1,3-β-d-glucan) and molecular tools. In recent years, the development of PCR for filamentous fungi (primarily Aspergillus or Mucorales) and the progress made in the standardization of fungal PCR technology, may lead to future advances in the field. The appropriate diagnostic approach for IMI should be individualized to each centre, taking into account the local epidemiology of IMI and the availability of diagnostic tests.

Galactofuranose antigens, a target for diagnosis of fungal infections in humans

The use of biomarkers for the detection of fungal infections is of interest to complement histopathological and culture methods. Since the production of antibodies in immunocompromised patients is scarce, detection of a specific antigen could be effective for early diagnosis. D-Galactofuranose (Galf) is the antigenic epitope in glycoconjugates of several pathogenic fungi. Since Galf is not biosynthesized by mammals, it is an attractive candidate for diagnosis of infection. A monoclonal antibody that recognizes Galf is commercialized for detection of aspergillosis. The linkage of Galf in the natural glycans and the chemical structures of the synthesized Galf-containing oligosaccharides are described in this paper. The oligosaccharides could be used for the synthesis of artificial carbohydrate-based antigens, not enough exploited for diagnosis.

D-Galactofuranose (Galf) is the unit in polysaccharides and glycoconjugates of several pathogenic fungi that is recognized by the immune system. Since Galf is not synthesized by mammals, it is an attractive candidate for diagnosis of infection. Since the production of antibodies in immunocompromised patients is scarce, detection of a specific antigen could be effective for early diagnosis. An antibody that recognizes Galf is commercialized for the detection of aspergillosis. Chemically synthesized Galf-containing oligosaccharides, reviewed in this paper, could therefore be used for the synthesis of artificial carbohydrate-based antigens and in diagnosis.

Molecular diagnosis of invasive mycoses of the central nervous system

INTRODUCTION

In September 2012, the Centers for Disease Control and Prevention (CDC) began investigating an outbreak of fungal meningitis among patients who had received contaminated preservative-free methyl prednisolone acetate injections from the New England Compounding Center in Framingham, Massachusetts. Thousands of patients were potentially exposed to tainted corticosteroids, but establishing the diagnosis of fungal meningitis during the nationwide outbreak was difficult because little was known about the natural history of the disease. Areas covered: The challenges associated with this outbreak highlighted the need for rapid and reliable methodologies to assist in the diagnosis of invasive mycoses of the central nervous system (IMCNS), which may be devastating and difficult to treat. In this paper, we review the causative agents of these potentially-lethal infections, which include cryptococcal meningitis, cerebral aspergillosis, and hematogenous Candida meningoencephalitis. Expert commentary: While microscopy, culture, and histopathologic identification of fungal pathogens remain the gold standard for diagnosis, new platforms and species-specific assays have recently emerged, including lateral flow immunoassays (LFA), matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), and multiplex PCR in conjunction with magnetic resonance (MR) to potentially aid in the diagnosis of IMCNS.

Enhancing melting curve analysis for the discrimination of loop-mediated isothermal amplification products from four pathogenic molds: Use of inorganic pyrophosphatase and its effect in reducing the variance in melting temperature values

Loop-mediated isothermal amplification (LAMP) is widely used for differentiating causative agents in infectious diseases. Melting curve analysis (MCA) in conjunction with the LAMP method reduces both the labor required to conduct an assay and contamination of the products. However, two factors influence the melting temperature (Tm) of LAMP products: an inconsistent concentration of Mg²⁺ ion due to the precipitation of Mg₂P₂O₇, and the guanine-cytosine (GC) content of the starting dumbbell-like structure. In this study, we investigated the influence of inorganic pyrophosphatase (PPase), an enzyme that inhibits the production of Mg₂P₂O₇, on the Tm of LAMP products, and examined the correlation between the above factors and the Tm value using MCA. A set of LAMP primers that amplify the ribosomal DNA of the large subunit of Aspergillus fumigatus, Penicillium expansum, Penicillium marneffei, and Histoplasma capsulatum was designed, and the LAMP reaction was performed using serial concentrations of these fungal genomic DNAs as templates in the presence and absence of PPase. We compared the Tm values obtained from the PPase-free group and the PPase-containing group, and the relationship between the GC content of the theoretical starting dumbbell-like structure and the Tm values of the LAMP product from each fungus was analyzed. The range of Tm values obtained for several fungi overlapped in the PPase-free group. In contrast, in the PPase-containing group, the variance in Tm values was smaller and there was no overlap in the Tm values obtained for all fungi tested: the LAMP product of each fungus had a specific Tm value, and the average Tm value increased as the GC% of the starting dumbbell-like structure increased. The use of PPase therefore reduced the variance in the Tm value and allowed the differentiation of these pathogenic fungi using the MCA method.

Sensitivity and Specificity of Histoplasma Antigen Detection by Enzyme Immunoassay

The objective of this study was to evaluate the sensitivity and specificity of an antigen enzyme immunoassay (EIA) on urine samples for the diagnosis of histoplasmosis in dogs. This retrospective medical records review included canine cases with urine samples submitted for Histoplasma EIA antigen assay between 2007 and 2011 from three veterinary institutions. Cases for which urine samples were submitted for Histoplasma antigen testing were reviewed and compared to the gold standard of finding Histoplasma organisms or an alternative diagnosis on cytology or histopathology. Sensitivity, specificity, negative predictive value, positive predictive value, and the kappa coefficient and associated confidence interval were calculated for the EIA-based Histoplasma antigen assay. Sixty cases met the inclusion criteria. Seventeen cases were considered true positives based on identification of the organism, and 41 cases were considered true negatives with an alternative definitive diagnosis. Two cases were considered false negatives, and there were no false positives. Sensitivity was 89.47% and the negative predictive value was 95.35%. Specificity and the positive predictive value were both 100%. The kappa coefficient was 0.9207 (95% confidence interval, 0.8131-1). The Histoplasma antigen EIA test demonstrated high specificity and sensitivity for the diagnosis of histoplasmosis in dogs.

Aspergillus PCR in serum for the diagnosis, follow-up and prognosis of invasive aspergillosis in neutropenic and nonneutropenic patients

We evaluated the usefulness of a serum Aspergillus PCR assay for the diagnosis and prognosis of invasive aspergillosis in a study involving 941 patients for a total of 5146 serum samples. Fifty-one patients had proven/probable aspergillosis. We compared galactomannan (GM), PCR and mycologic analysis of pulmonary samples in both neutropenic and nonneutropenic patients. PCR performed in serum yielded 66.7% sensitivity, 98.7% specificity, 75.6% positive predictive value and 98.0% negative predictive value, while the GM index yielded 78.4% sensitivity, 87.5% specificity, 27% positive predictive value and 98.6% negative predictive value. The inclusion of PCR in the European Organization for Research and Treatment of Cancer (EORTC) and the Mycosis Study Group (MSG) mycologic criteria permitted the reclassification of nine other cases from possible to probable aspergillosis and increased the sensitivity to 71.7%. Combining the GM index with serum PCR increased the detection rate of invasive aspergillosis with 88.2% sensitivity. PCR was systematically negative in 16 patients with noninvasive forms of aspergillosis (namely aspergilloma and chronic aspergillosis). Remaining PCR positive after a period of 14 to 20 days of treatment was related to poor outcome at 30 and 90 days. Our results also indicate that, unlike the determination of the GM index, the initial fungus load as determined by PCR was highly predictive of 90-day mortality, with the rate of the latter being 15.8% for patients with <150 copies/mL vs. 73.2% for patients at or above that cutoff (p <0.0001). Therefore, PCR appears to be a powerful and interesting tool for the identification of patients with invasive aspergillosis who might benefit from more intense care.

Nonspecific elevation of serum Aspergillus galactomannan antigen levels in patients with rheumatoid arthritis

BACKGROUND

Infections are an important cause of morbidity and mortality in patients with rheumatoid arthritis. Patients receiving immunosuppressive or anti-tumor necrosis factor (TNF) agents are vulnerable to fungal infections, including those derived from Aspergillus species. Detection of the Aspergillus galactomannan antigen in serum is useful for the early diagnosis of invasive aspergillosis in patients with hematological malignancies. However, its usefulness for detecting early invasive aspergillosis in rheumatoid arthritis patients remains unestablished.

METHODS

Galactomannan antigen levels were measured in 340 patients (311 female patients). For patients who exhibited galactomannan antigen levels ≥0.5 during the initial examination, a second examination was performed 3-6 months later. Conventional blood tests and chest radiography were also performed.

RESULTS

Elevated galactomannan antigen levels (≥0.5) were observed in 62 (18.2%) of 340 patients during the initial examination. A second examination was performed in 56 of 62 patients, 50 of whom exhibited elevated antigen levels. Elevated antigen levels were not associated with the use of any drug including anti-TNF agents. Serum galactomannan antigen levels were correlated with the albumin/globulin ratio (r=-0.19, p<0.001), γ-globulin (%; r=0.17, p=0.001), and hemoglobin concentration (r=-0.15, p=0.005). No patient was clinically diagnosed with invasive aspergillosis during the study period.

CONCLUSIONS

Serum galactomannan antigen levels are frequently elevated in a nonspecific manner in patients with rheumatoid arthritis.

Evaluation of the Double Agar Gel Immunodiffusion Test and of the Enzyme-Linked Immunosorbent Assay in the Diagnosis and Follow-Up of Patients with Chronic Pulmonary Aspergillosis

The diagnosis of chronic pulmonary aspergillosis (CPA) depends on the radiologic image and the identification of specific antibodies. The present study aimed to evaluate accuracy parameters of enzyme-linked immunosorbent assay (ELISA) and of the determination of serum galactomannan level in the diagnosis of patients with CPA, comparing these results with the double agar gel immunodiffusion (DID) test. In addition, the prevalence of cross-reactivity and the serological progression after treatment were evaluated by comparing DID and ELISA. Six study groups were formed: G1: 22 patients with CPA, 17 of whom had Aspergillus fungus ball, one chronic cavitary pulmonary aspergillosis (CCPA) and four chronic fibrosing pulmonary aspergillosis (CFPA); G2: 28 patients with pulmonary tuberculosis (TB); G3: 23 patients with histoplasmosis (HST); G4: 50 patients with paracoccidioidomycosis (PCM); G5: 20 patients with cryptococcosis (CRC); and G6: 200 healthy controls. Serum antibodies were measured by DID and ELISA, with two antigen preparations—Aspergillus fumigatus (DID₁, ELISA₁) and a pool of A. fumigatus, A. flavus and A. niger antigens (DID₂, ELISA₂). The Platélia Aspergillus Enzyme Immunoassay (EIA) kit was used to measure galactomannan. The cut-off points of ELISA were determined for each antigen preparation and for the 95% and 99% confidence intervals. Despite the low sensitivity, DID was the technique of choice due to its specificity, positive and negative predictive values and positive likelihood ratio–especially with the antigen pool and due to the low frequency of cross-reactivity. ELISA₁ and a 0.090 cut-off showed high sensitivity, specificity and negative predictive value, but a high frequency of cross-reactivity with CRC. The best degree of agreement was observed between ELISA₁ and ELISA₂. The detection of serum galactomannan showed high sensitivity, comparable to ELISA₂. The immunodiffusion test showed an excellent relationship with the progression after treatment, which made it the reaction of choice for patient follow-up.