Value of antigen detection using an enzyme immunoassay in the diagnosis and prediction of invasive aspergillosis in two adult and pediatric hematology units during a 4-year prospective study

COVID-19 Associated Pulmonary Aspergillosis (CAPA): Hospital or Home Environment as a Source of Life-Threatening Aspergillus fumigatus Infection?

Most cases of invasive aspergillosis are caused by Aspergillus fumigatus, whose conidia are ubiquitous in the environment. Additionally, in indoor environments, such as houses or hospitals, conidia are frequently detected too. Hospital-acquired aspergillosis is usually associated with airborne fungal contamination of the hospital air, especially after building construction events. A. fumigatus strain typing can fulfill many needs both in clinical settings and otherwise. The high incidence of aspergillosis in COVID patients from our hospital, made us wonder if they were hospital-acquired aspergillosis. The purpose of this study was to evaluate whether the hospital environment was the source of aspergillosis infection in CAPA patients, admitted to the Hospital Universitario Central de Asturias, during the first and second wave of the COVID-19 pandemic, or whether it was community-acquired aspergillosis before admission. During 2020, sixty-nine A. fumigatus strains were collected for this study: 59 were clinical isolates from 28 COVID-19 patients, and 10 strains were environmentally isolated from seven hospital rooms and intensive care units. A diagnosis of pulmonary aspergillosis was based on the ECCM/ISHAM criteria. Strains were genotyped by PCR amplification and sequencing of a panel of four hypervariable tandem repeats within exons of surface protein coding genes (TRESPERG). A total of seven genotypes among the 10 environmental strains and 28 genotypes among the 59 clinical strains were identified. Genotyping revealed that only one environmental A. fumigatus from UCI 5 (box 54) isolated in October (30 October 2020) and one A. fumigatus isolated from a COVID-19 patient admitted in Pneumology (Room 532-B) in November (24 November 2020) had the same genotype, but there was a significant difference in time and location. There was also no relationship in time and location between similar A. fumigatus genotypes of patients. The global A. fumigatus, environmental and clinical isolates, showed a wide diversity of genotypes. To our knowledge, this is the first study monitoring and genotyping A. fumigatus isolates obtained from hospital air and COVID-19 patients, admitted with aspergillosis, during one year. Our work shows that patients do not acquire A. fumigatus in the hospital. This proves that COVID-associated aspergillosis in our hospital is not a nosocomial infection, but supports the hypothesis of “community aspergillosis” acquisition outside the hospital, having the home environment (pandemic period at home) as the main suspected focus of infection.

Diagnostic Value of Galactomannan in Bronchoalveolar Lavage Fluid for Chronic Respiratory Disease with Pulmonary Aspergillosis

The objective of this study was to explore the diagnostic value of the bronchoalveolar lavage fluid galactomannan (BALF GM) test for chronic respiratory disease with pulmonary aspergillosis and to establish the optimal cutoff value. Samples from a total of 309 chronic respiratory disease patients seen at the respiratory medicine department of Peking University Shenzhen Hospital from September 2016 to September 2019 were analyzed. According to the diagnostic criteria, we divided the patients into a case group (n = 79, comprising 25 proven cases and 54 probable cases) and a control group (n = 230). Bronchoalveolar lavage fluid was collected, and the BALF GM test results were analyzed. A nonparametric rank sum test showed that the mean rank of the case group was 255.30, which was higher than that of the control group (120.55). The Z-value was -11.567 (P = 0.000), indicating that the general distributions of BALF GM differed between the two groups. A BALF GM cutoff value of 0.88 showed the highest diagnostic efficacy for pulmonary aspergillosis. The sensitivity, specificity, positive predictive value, and negative predictive value were 77.2%, 93%, 79.2%, and 92.2%, respectively. As the cutoff value increased, the specificity and sensitivity of the BALF GM test increased and decreased, respectively. The BALF GM test can be used confirm the diagnosis of patients with pulmonary aspergillosis and chronic respiratory disease. The optimum BALF GM cutoff value is 0.88.

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.

Invasive pulmonary aspergillosis in critically ill patients with hematological malignancies

PURPOSE

Invasive pulmonary aspergillosis (IPA) is a dreadful event in patients with hematological malignancies (HM). Recent advances have standardized diagnostic, prophylactic and curative therapeutic strategies. We sought to assess whether these advances actually translate into improved survival in critically ill patients with acute respiratory failure and IPA.

METHODS

This was a retrospective, multicenter study. Adult patients with HM, IPA, admitted to the ICU for acute respiratory failure over a 20-year period (January 1998-December 2017) were included. A cox regression model was used to identify variables independently associated with day-90 survival.

RESULTS

Overall, 219 patients were included [138 (63%) men, median age 55 (IQR 44-64)]. Acute myeloid leukemia (30.1%) and non-Hodgkin lymphoma (22.8%) were the most frequent malignancies, and 53 (24.2%) were allogeneic stem cell recipients. Day-1 SOFA score was 9 [7-12]. Most patients presented with probable IPA, whereas 15 (7%) underwent lung biopsies or pleurocentesis and met criteria for proven IPA. Overall ICU and day-90 mortality were, respectively, 58.4% and 75.2% (80.4% if invasive mechanical ventilation) without any significant improvement over time. By multivariable analysis adjusted on day-1 SOFA score and ventilation strategies, voriconazole use (HR 0.49, CI 95 0.34-0.73, p < 0.001) and an ICU admission after 2010 (HR 0.67, 0.45-0.99, p = 0.042) were associated with increased survival, whereas a diffuse radiologic pattern (HR 2.07, CI 95 1.33-3.24, p = 0.001) and delayed admission to the ICU (HR 1.51, CI 95 1.05-2.16, p = 0.026) were independently associated with increased mortality.

CONCLUSIONS

IPA is associated with high mortality rates in critically ill patients with acute respiratory failure. Routine voriconazole and prompt ICU admission are warranted.

Development of a nano-gold immunodiagnostic assay for rapid on-site detection of invasive aspergillosis

Introduction. Timely detection of invasive aspergillosis (IA) caused by fungal pathogens, i.e. Aspergillus fumigatus and Aspergillus flavus, in immunocompromised patients is crucial in preventing high mortality.Aim. To develop a simple immunoassay for the detection of galactomannan (GM), an IA biomarker.Methodology. GM from A. fumigatus and A. flavus clinical strains was purified and characterized by X-ray diffraction, IR spectroscopy and ¹³C/¹H nuclear magnetic resonance (NMR) for polyclonal antibody (pAb) production in rabbits. An enzyme-linked immunosorbent assay (ELISA) was standardized using concanavalin A to capture Aspergillus GM and pAbs to detect it. Gold nanoparticles (AuNPs) were synthesized and conjugated to pAbs for the development of a dot-blot immunoassay. The developed dot-blot was evaluated with 109 clinical serum and bronchoalveolar lavage samples.Results. Spectroscopy studies characterized the d-galactofuranosyl groups of GM responsible for the immune response and generation of pAbs. The ELISA employing pAbs showed a sensitivity of 1 ng ml^-1 for Aspergillus GM. Furthermore, a sensitive, visual, rapid dot-blot assay developed by the conjugation of pAbs to AuNPs (~24±5 nm size, -36±2 mV zeta potential) had a detection limit of 1 pg ml^-1 in serum. The pAbs interacted with Aspergillus spp. but did not cross-react with other fungal pathogen genera such as Penicillium and Candida. Evaluation of the dot-blot with 109 clinical samples showed high sensitivity (80 %) and specificity (93.2 %), with an overall assay accuracy of 89%.Conclusion. The developed nano-gold immunodiagnostic assay has immense potential for practical use in rapid, specific and sensitive on-site diagnosis of IA, even under resource-limited settings.

Diagnosis of invasive fungal diseases in haematology and oncology: 2018 update of the recommendations of the infectious diseases working party of the German society for hematology and medical oncology (AGIHO)

Invasive fungal diseases (IFD) are a primary cause of morbidity and mortality in patients with haematological malignancies. These infections are mostly life-threatening and an early diagnosis and initiation of appropriate antifungal therapy are essential for the clinical outcome. Most commonly, Aspergillus and Candida species are involved. However, other Non-Aspergillus moulds are increasingly identified in case of documented IFD. For definite diagnosis of IFD, a combination of diagnostic tools have to be applied, including conventional mycological culture and non-conventional microbiological tests such as antibody/antigen and molecular tests, as well as histopathology and radiology. Although varying widely in cancer patients, the risk of invasive fungal infection is highest in those with allogeneic stem cell transplantation and those with acute leukaemia and markedly lower in patients with solid cancer. Since the last edition of Diagnosis of Invasive Fungal Diseases recommendations of the German Society for Hematology and Oncology in 2012, integrated care pathways have been proposed for the management and therapy of IFDs with either a diagnostic driven strategy as opposed to a clinical or empirical driven strategy. This update discusses the impact of this additional evidence and effective revisions.

Diagnostic Approaches for Invasive Aspergillosis-Specific Considerations in the Pediatric Population

Invasive aspergillosis (IA) is a major cause of morbidity and mortality in children with hematological malignancies and those undergoing hematopoietic stem cell transplantation. Similar to immunocompromised adults, clinical signs, and symptoms of IA are unspecific in the pediatric patient population. As early diagnosis and prompt treatment of IA is associated with better outcome, imaging and non-invasive antigen-based such as galactomannan or ß-D-glucan and molecular biomarkers in peripheral blood may facilitate institution and choice of antifungal compounds and guide duration of therapy. In patients in whom imaging studies suggest IA or another mold infection, invasive diagnostics such as bronchoalveolar lavage and/or bioptic procedures should be considered. Here we review the current data of diagnostic approaches for IA in the pediatric setting and highlight the major differences of performance and clinical utility of the tests between children and adults.

Role of Molecular Biomarkers in the Diagnosis of Invasive Fungal Diseases in Children

Invasive fungal diseases are important clinical problems that are often complicated by severe illness and therefore the inability to use invasive measures to definitively diagnose the disease. Tests for a range of fungal biomarkers that do not require an invasive sample-collection procedure have been incorporated into adult clinical practice, but pediatric data and pediatric-specific recommendations for some of these diagnostic tools are lacking. In this review, we summarize the published literature and contemporary strategies for using the biomarkers galactomannan, (1→3)-β-d-glucan, Candida mannan antigen and anti-mannan antibody, and fungal polymerase chain reaction for diagnosing invasive fungal disease in children. Data on biomarker use in neonates and children with cancer, history of hematopoietic stem cell transplant, or primary immunodeficiency are included. Fungal biomarker tests performed on blood, other body fluids, or tissue specimens represent promising adjuncts to the diagnostic armamentarium in populations with a high prevalence of invasive fungal disease, but substantial gaps exist in the correct use and interpretation of these diagnostic tools in pediatric patients.

Current Algorithms in Fungal Diagnosis in the Immunocompromised Host

Invasive fungal diseases (IFDs) are a major cause of morbidity and mortality in immunocompromised patients such as patients with hematological malignancies or allogeneic hematopoietic stem cell transplant recipients. Whereas the definite diagnosis of IFD requires invasive diagnostic procedures, imaging and noninvasive diagnostic assays may help in decision making with regard to the institution and the choice of antifungal agents, the duration of therapy, surgical intervention, and monitoring of fungal manifestations.Unfortunately, signs and symptoms of IFD are often nonspecific in the immunocompromised patient. Therefore, in immunocompromised patients with suspected IFD, all samples collected need to be cultured for fungi, and, in the case of specimens obtained by invasive diagnostic procedures, also microscopically examined. For high sensitivity of the cultural and microscopic approaches, specific media and stains, respectively, are crucial. Non-culture based method such as the detection of galactomannan or ß-d-glucan and molecular tools such as polymerase chain reaction may help in the early diagnosis of IFD. Imaging studies may be indicative for IFD, but invasive diagnostics such as bronchoalveolar lavage and/or biopsy should be pursued in order to identify the causative pathogen. This chapter summarizes the current knowledge on diagnosing IFD and proposes practical help in the use of diagnostic tools.

Immunoproteomics of Aspergillus for the development of biomarkers and immunotherapies

Filamentous fungi of the genus Aspergillus play significant roles as pathogens causing superficial and invasive infections as well as allergic reactions in humans. Particularly invasive mycoses caused by Aspergillus species are characterized by high mortality rates due to difficult diagnosis and insufficient antifungal therapy. The application of immunoproteomic approaches has a great potential to identify new targets for the diagnosis, therapy, and vaccine development of diseases caused by Aspergillus species. Serological proteome analyses (SERPA) that combine 2D electrophoresis with Western blotting are still one of the most popular techniques for the identification of antigenic proteins. However, recently a growing number of approaches have been developed to identify proteins, which either provoke an antibody response or which represent targets of T-cell immunity in patients with allergy or fungal infections. Here, we review advances in the studies of immune responses against pathogenic Aspergilli as well as the current status of diagnosis and immunotherapy of Aspergillus infections.

Galactomannan detection for invasive aspergillosis in immunocompromised patients

BACKGROUND

Invasive aspergillosis is the most common life-threatening opportunistic invasive mycosis in immunocompromised patients. A test for invasive aspergillosis should neither be too invasive nor too great a burden for the already weakened patient. The serum galactomannan enzyme-linked immunosorbent assay (ELISA) seems to have the potential to meet both requirements.

OBJECTIVES

To obtain summary estimates of the diagnostic accuracy of galactomannan detection in serum for the diagnosis of invasive aspergillosis.

SEARCH METHODS

We searched MEDLINE, EMBASE and Web of Science with both MeSH terms and text words for both aspergillosis and the sandwich ELISA. We checked the reference lists of included studies and review articles for additional studies. We conducted the searches in February 2014.

SELECTION CRITERIA

We included cross-sectional studies, case-control designs and consecutive series of patients assessing the diagnostic accuracy of galactomannan detection for the diagnosis of invasive aspergillosis in patients with neutropenia or patients whose neutrophils are functionally compromised. The reference standard was composed of the criteria given by the European Organization for Research and Treatment of Cancer (EORTC) and the Mycoses Study Group (MSG).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed quality and extracted data. We carried out meta-analysis using the bivariate method. We investigated sources of heterogeneity by adding potential sources of heterogeneity to the model as covariates.

MAIN RESULTS

We included 54 studies in the review (50 in the meta-analyses), containing 5660 patients, of whom 586 had proven or probable invasive aspergillosis. When using an optical density index (ODI) of 0.5 as a cut-off value, the sensitivity of the test was 82% (73% to 90%) and the specificity was 81% (72% to 90%). At a cut-off value of 1.0 ODI, the sensitivity was 72% (65% to 80%) and the specificity was 88% (84% to 92%). At a cut-off value of 1.5 ODI, the sensitivity was 61% (47% to 75%) and the specificity was 93% (89% to 97%). None of the potential sources of heterogeneity had a statistically significant effect on either sensitivity or specificity.

AUTHORS' CONCLUSIONS

If we used the test at a cut-off value of 0.5 ODI in a population of 100 patients with a disease prevalence of 9% (overall median prevalence), two patients who have invasive aspergillosis would be missed (sensitivity 82%, 18% false negatives), and 17 patients would be treated unnecessarily or referred unnecessarily for further testing (specificity 81%, 19% false negatives). If we used the test at a cut-off value of 1.5 in the same population, that would mean that four invasive aspergillosis patients would be missed (sensitivity 61%, 39% false negatives), and six patients would be treated or referred for further testing unnecessarily (specificity 93%, 7% false negatives). These numbers should, however, be interpreted with caution because the results were very heterogeneous.

Aspergillus Thyroiditis after Allogeneic Hematopoietic Stem Cell Transplantation

Aspergillus thyroiditis is a rare disorder detected in immunocompromised patients during disseminated infections. Early management is essential to prevent high mortality. A 61-year-old allogeneic stem cell male recipient presented with painful thyroid nodular enlargement. He had low TSH and low free T4 levels. The thyroid ultrasound showed a hypoechoic nodule; biopsy indicated suppurative Aspergillus thyroiditis. He was successfully treated by amphotericin B.

Aspergillus Polymerase Chain Reaction: Systematic Review of Evidence for Clinical Use in Comparison With Antigen Testing

BACKGROUND

Aspergillus polymerase chain reaction (PCR) was excluded from the European Organisation for the Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG) definitions of invasive fungal disease because of limited standardization and validation. The definitions are being revised.

METHODS

A systematic literature review was performed to identify analytical and clinical information available on inclusion of galactomannan enzyme immunoassay (GM-EIA) (2002) and β-d-glucan (2008), providing a minimal threshold when considering PCR. Categorical parameters and statistical performance were compared.

RESULTS

When incorporated, GM-EIA and β-d-glucan sensitivities and specificities for diagnosing invasive aspergillosis were 81.6% and 91.6%, and 76.9% and 89.4%, respectively. Aspergillus PCR has similar sensitivity and specificity (76.8%-88.0% and 75.0%-94.5%, respectively) and comparable utility. Methodological recommendations and commercial PCR assays assist standardization. Although all tests have limitations, currently, PCR is the only test with independent quality control.

CONCLUSIONS

We propose that there is sufficient evidence that is at least equivalent to that used to include GM-EIA and β-d-glucan testing, and that PCR is now mature enough for inclusion in the EORTC/MSG definitions.

Invasive fungal infections in transplant recipients

Invasive fungal infections are an important cause of morbidity and mortality in hematopoietic stem cell transplant and solid organ transplant recipients. Evolving transplant modalities and techniques, complex and extensive immunosuppressant strategies, and the increased use of broad spectrum antifungal prophylaxis has greatly impacted the epidemiology and temporal pattern of invasive fungal infections in the transplant population. The goal of this article is to provide an up-to-date review of the most commonly encountered invasive fungal infections seen in transplant recipients, including epidemiology, risk factors, clinical features, diagnostic dilemmas, management and their overall influence on outcomes.

Use and limits of (1-3)-β-d-glucan assay (Fungitell), compared to galactomannan determination (Platelia Aspergillus), for diagnosis of invasive aspergillosis

This study was undertaken to examine the performance of the Fungitell β-glucan (BG) assay, to compare it with that of the galactomannan (GM) test for the diagnosis of invasive aspergillosis (IA) in patients with hematological malignancies, and to examine the rates of false-positive BG and GM test results due to β-lactam antibiotics among sera of patients with Gram-positive or Gram-negative bacteremia and selected sera with false-positive results from the GM test. Serum samples from 105 patients with proven (n = 14) or probable (n = 91) IA, 97 hematology patients at risk for invasive fungal infections, 50 healthy blood donors, and 60 patients with bacteremia were used to study the sensitivities and specificities of the assays. The GM test was more specific than the BG assay (97% versus 82%, respectively; P = 0.0001) and the BG assay was more sensitive than the GM test (81% versus 49%, respectively; P < 0.0001) for IA diagnosis. The study of 49 separate batches of β-lactam antibiotics showed high and very similar rates of false-positive results for the GM and BG assays (29 and 33%, respectively; P = 0.82) but with an almost complete lack of concordance between the 2 assays. For patients with bacteremia, the rate of false-positive results was much higher with the BG test than with the GM test (37% versus 2%, respectively; P < 0.0001), with no significant difference between Gram-positive and Gram-negative bacteremia. In conclusion, the BG test may be useful for the diagnosis of IA because of its high sensitivity in comparison with the GM test, but the overall benefit of this assay remains limited because of its inadequate specificity and its cost.

Fungal diagnostics

Early diagnosis of fungal infection is critical to effective treatment. There are many impediments to diagnosis such as a diminishing number of clinical mycologists, cost, time to result, and requirements for sensitivity and specificity. In addition, fungal diagnostics must meet the contrasting needs presented by the increasing diversity of fungi found in association with the use of immunosuppressive agents in countries with high levels of medical care and the need for diagnostics in resource-limited countries where large numbers of opportunistic infections occur in patients with AIDS. Traditional approaches to diagnosis include direct microscopic examination of clinical samples, histopathology, culture, and serology. Emerging technologies include molecular diagnostics and antigen detection in clinical samples. Innovative new technologies that use molecular and immunoassay platforms have the potential to meet the needs of both resource-rich and resource-limited clinical environments.

Invasive pulmonary aspergillosis

In susceptible patients, invasive aspergillosis has a high incidence and a mortality of up to 80%. The diagnosis of this condition is difficult, especially in the early stages of the disease and, as a consequence, antifungal therapy, despite its expense and toxicity, is often initiated empirically. Until recently, there were very few effective antifungal agents for established invasive aspergillosis, but the introduction of two new drugs, voriconazole and caspofungin, has increased the treatment options. These newer antifungal therapies, combined with improved early diagnosis due to the introduction of newer microbiologic techniques, offer the hope that there will be a significant improvement in the substantial morbidity and mortality associated with invasive aspergillosis over the next 5 years.

Galactomannan antigen detection in the diagnosis of invasive aspergillosis

Invasive aspergillosis is a serious and lethal infection among immunocompromised patients, with reported mortality rates as high as 74-92%. The high mortality is related to the severe immunosuppression experienced by these patients as well as the difficulties for physicians in arriving at a timely diagnosis. Definitive diagnostic procedures (tissue biopsy for histopathology and culture) are often precluded by severe cytopenias and coagulation abnormalities. The development of minimally invasive, nonculture diagnostic methods is a major advance in the early diagnosis of invasive aspergillosis. Galactomannan is a heteropolysaccharide (mannan core and side residues of galactofuranosyl units) present in the cell wall of Aspergillus spp. The double sandwich enzyme immunoassay, which detects galactomannan in serum samples, has been available in Europe for almost a decade and in the USA since May 2003, for the diagnosis of invasive aspergillosis. However, availability of the double galactomannan enzyme immunoassay is center variable in the USA and, although its analytical performance in the diagnosis of invasive aspergillosis is well documented, its routine use in clinical practice is limited. As an adjunct in the diagnosis and management of invasive aspergillosis, incorporation of the galactomannan enzyme immunoassay into clinical trials will help to further define its role.

Aspergillus colonization in patients with bronchogenic carcinoma

Background

Aspergillus antigens such as galactomannan antigen, a cell wall polysaccharide, can be detected in patient’s serum or bronchoalveolar lavage. To study the prevalence of Aspergillus infection in patients with bronchogenic carcinoma, we measured galactomannan antigen in serum and bronchoalveolar lavage samples of patients with bronchogenic carcinoma.

Methods

The study was conducted on 45 bronchogenic carcinoma patients. The diagnosis of lung cancer was confirmed by bronchoscopy, histopathological and radiological examinations. Bronchoalveolar lavage fluid collected from each patient by fiberoptic bronchoscopy was subjected to direct microscopy and culture on Sabouraud’s dextrose agar and Czapek-Dox agar, and Aspergillus galactomannan antigen was measured in serum and bronchoalveolar lavage samples.

Results

The majority of patients were male (93.3%) in the age group 51–60 years, 88.9% were addicted to gutka chewing, and 82.1% were addicted to smoking. Most patients complained of cough (73%) and shortness of breath (51.1%). Squamous cell carcinoma (64.4%) was the most common malignancy, followed by adenocarcinoma (13.3%). On culture of bronchoalveolar lavage samples, 35.5% showed growth of Aspergillus spp. ( Aspergillus fumigatus in 17.8%, Aspergillus flavus in 13.3%, and Aspergillus niger in 4.4%). Galactomannan antigen was detected in 58.3% of bronchoalveolar lavage samples and 47.2% of serum samples.

Conclusions

There is a high prevalence of aspergillosis in patients with lung carcinoma, especially among smokers and gutka chewers.

Why is biopsy of suspected fungal lung lesions necessary?

The recognition of antifungal resistance is necessary for the choice of the appropriate treatment in patients with invasive fungal disease. In this case report, the need for a computed tomography-guided percutaneous lung biopsy of a suspected fungal lesion in a patient treated for acute leukemia is demonstrated. Detection of Amphothericin-B resistant Aspergillus flavus infection has prompted the switch in antifungal therapy, followed by full resolution of symptoms, completion of chemotherapy and remission since then.

The Role of Biomarkers for Diagnosis of and Therapeutic Decisions Related to Invasive Aspergillosis in Children

Invasive aspergillosis (IA) is a feared opportunistic infection for many immuncompromised children resulting in significant morbidity and mortality. Timely diagnosis based on traditional testing modalities and clinical evaluation has proven to be challenging. Assays designed to measure IA biomarkers such as galactomannan (GM) and beta-D-glucan (BG) represent a potential significant improvement in the ability to diagnose pediatric IA. However, as with any new diagnostic tool, clinicians need to be aware of the operating characteristics of these assays in order to apply them in the appropriate settings. Published adult and pediatric data regarding GM and BG testing are reviewed and guidance regarding the appropriate utility of these assays in children is offered.

Quantitative detection of Aspergillus spp. by real-time nucleic acid sequence-based amplification

Rapid and quantitative detection of Aspergillus from clinical samples may facilitate an early diagnosis of invasive pulmonary aspergillosis (IPA). As nucleic acid-based detection is a viable option, we demonstrate that Aspergillus burdens can be rapidly and accurately detected by a novel real-time nucleic acid assay other than qPCR by using the combination of nucleic acid sequence-based amplification (NASBA) and the molecular beacon (MB) technology. Here, we detail a real-time NASBA assay to determine quantitative Aspergillus burdens in lungs and bronchoalveolar lavage (BAL) fluids of rats with experimental IPA.

Galactomannan Antigen Testing for Diagnosis of Invasive Aspergillosis in Pediatric Hematology Patients

OBJECTIVE

Invasive aspergillosis (IA) can cause significant morbidity and mortality in immunocompromised children. The galactomannan (GM) enzyme immunoassay (EIA) has been shown in adult studies to be a useful adjunct in diagnosing IA. Data on this assay in children are limited by small sample sizes and conflicting results; false-positive assays were a concern in historical studies. We sought to evaluate the GM EIA in a large cohort of children who received intensive chemotherapy and/or hematopoietic stem cell transplant. A focus was placed on evaluating the assay specificity, and the potential of measuring GM antigen in urine.

METHODS

A multicenter prospective observational study in children with anticipated prolonged neutropenia was performed. Serum specimens were collected twice weekly, and urine was collected once weekly during neutropenic periods. Operating characteristics were calculated using the GM EIA optical density index cutoffs of 0.5 and 1.0 for both serum and urine specimens.

RESULTS

At least one serum or urine specimen was tested from 198 patients. Ten patients had one or more repeatedly positive serum specimens, while 37 patients had one or more repeatedly positive urine specimens. The specificity of serum and urine testing was 95% and 80%, respectively. Although the urine test resulted in a higher false positivity rate, it successfully identified the only case of probable IA.

CONCLUSIONS

Data suggest that the serum GM EIA does not provide frequent false-positive results as previously reported. Screening for galactomannan, or a related antigen in urine, needs to be further evaluated as it may be amenable to development of surveillance strategies.

False-positive Aspergillus antigenemia due to blood product conditioning fluids

The presence of Aspergillus antigens in blood transfusion components from different manufacturers was analyzed. Galacomannans were found in transfused patients, pooled platelet concentrates, fresh frozen plasma, and packed red cells collected using Fresenius Kabi bags. Galacomannans were also found in blood collection anticoagulant and platelet additive solution from this manufacturer.

Diagnosis of invasive fungal infections in hematology and oncology--guidelines from the Infectious Diseases Working Party in Haematology and Oncology of the German Society for Haematology and Oncology (AGIHO)

Invasive fungal infections (IFIs) are a primary cause of morbidity and mortality in patients with hematological malignancies. Establishing a definite diagnosis of IFI in immunocompromised patients is particularly challenging and time consuming, but delayed initiation of antifungal treatment increases mortality. The limited overall outcome has led to the strategy of initiating either 'empirical' or 'preemptive' antifungal therapy before the final diagnosis. However, diagnostic procedures have been vastly improved in recent years. Particularly noteworthy is the introduction of newer imaging techniques and non-culture methods, including antigen-based assays, metabolite detection and molecular detection of fungal DNA from body fluid samples. Though varying widely in cancer patients, the risk of IFI is highest in those with allogeneic stem cell transplantation and those with acute leukemia. The AGIHO presents recommendations for the diagnosis of IFIs with risk-adapted screening concepts for febrile episodes in patients with haemato-oncological disorders.

Invasive aspergillosis in hematopoietic stem cell and solid organ transplantation

Invasive aspergillosis (IA) is currently an important cause of morbidity and mortality in hematopoietic stem cell transplant and solid organ transplant recipients. A high index of suspicion and careful clinical and radiological examinations are the keys to identifying infected patients early. Chest computerized axial tomography is extremely useful in diagnosing pulmonary aspergillosis. Microbiologic or histologic identification of infection, however, remain essential. Successful management of invasive fungal infections depends on timely and appropriate treatment. There are multiple variables associated with survival in transplant patients with IA. Understanding these prognostic factors may assist in the development of treatment algorithms and clinical trials. In contrast to adult patients, large prospective comparative studies have not been performed in pediatric patients with IA. Moreover, pediatric subgroups have not been analyzed in published studies that include a broader age range. Clinicians treating pediatric IA are largely left with the results of uncontrolled trials, observatory surveys, salvage therapy data and extrapolations from adult studies to guide their treatment choices. The aim of this article is to state the main characteristics of IA in both pediatric and adult populations.

Design issues in a randomized controlled trial of a pre-emptive versus empiric antifungal strategy for invasive aspergillosis in patients with high-risk hematologic malignancies

Invasive aspergillosis (IA) is a major cause of mortality in patients with hematological malignancies, due largely to the inability of traditional culture and biopsy methods to make an early or accurate diagnosis. Diagnostic accuracy studies suggest that Aspergillus galactomannan (GM) enzyme immunoassay (ELISA) and Aspergillus PCR-based methods may overcome these limitations, but their impact on patient outcomes should be evaluated in a diagnostic randomized controlled trial (D-RCT). This article describes the methodology of a D-RCT which compares a new pre-emptive strategy (GM-ELISA- and Aspergillus PCR-driven antifungal therapy) with the standard fever-driven empiric antifungal treatment strategy. Issues including primary end-point and patient selection, duration of screening, choice of tests for the pre-emptive strategy, antifungal prophylaxis and bias control, which were considered in the design of the trial, are discussed. We suggest that the template presented herein is considered by researchers when evaluating the utility of new diagnostic tests (ClinicalTrials.gov number, NCT00163722).

Clinical practice guideline for the use of antimicrobial agents in neutropenic patients with cancer: 2010 update by the infectious diseases society of america

This document updates and expands the initial Infectious Diseases Society of America (IDSA) Fever and Neutropenia Guideline that was published in 1997 and first updated in 2002. It is intended as a guide for the use of antimicrobial agents in managing patients with cancer who experience chemotherapy-induced fever and neutropenia. Recent advances in antimicrobial drug development and technology, clinical trial results, and extensive clinical experience have informed the approaches and recommendations herein. Because the previous iteration of this guideline in 2002, we have a developed a clearer definition of which populations of patients with cancer may benefit most from antibiotic, antifungal, and antiviral prophylaxis. Furthermore, categorizing neutropenic patients as being at high risk or low risk for infection according to presenting signs and symptoms, underlying cancer, type of therapy, and medical comorbidities has become essential to the treatment algorithm. Risk stratification is a recommended starting point for managing patients with fever and neutropenia. In addition, earlier detection of invasive fungal infections has led to debate regarding optimal use of empirical or preemptive antifungal therapy, although algorithms are still evolving. What has not changed is the indication for immediate empirical antibiotic therapy. It remains true that all patients who present with fever and neutropenia should be treated swiftly and broadly with antibiotics to treat both gram-positive and gram-negative pathogens. Finally, we note that all Panel members are from institutions in the United States or Canada; thus, these guidelines were developed in the context of North American practices. Some recommendations may not be as applicable outside of North America, in areas where differences in available antibiotics, in the predominant pathogens, and/or in health care-associated economic conditions exist. Regardless of venue, clinical vigilance and immediate treatment are the universal keys to managing neutropenic patients with fever and/or infection.

Executive Summary: Clinical Practice Guideline for the Use of Antimicrobial Agents in Neutropenic Patients with Cancer: 2010 Update by the Infectious Diseases Society of America

This document updates and expands the initial Infectious Diseases Society of America (IDSA) Fever and Neutropenia Guideline that was published in 1997 and first updated in 2002. It is intended as a guide for the use of antimicrobial agents in managing patients with cancer who experience chemotherapy-induced fever and neutropenia.

Recent advances in antimicrobial drug development and technology, clinical trial results, and extensive clinical experience have informed the approaches and recommendations herein. Because the previous iteration of this guideline in 2002, we have a developed a clearer definition of which populations of patients with cancer may benefit most from antibiotic, antifungal, and antiviral prophylaxis. Furthermore, categorizing neutropenic patients as being at high risk or low risk for infection according to presenting signs and symptoms, underlying cancer, type of therapy, and medical comorbidities has become essential to the treatment algorithm. Risk stratification is a recommended starting point for managing patients with fever and neutropenia. In addition, earlier detection of invasive fungal infections has led to debate regarding optimal use of empirical or preemptive antifungal therapy, although algorithms are still evolving.

What has not changed is the indication for immediate empirical antibiotic therapy. It remains true that all patients who present with fever and neutropenia should be treated swiftly and broadly with antibiotics to treat both gram-positive and gram-negative pathogens.

Finally, we note that all Panel members are from institutions in the United States or Canada; thus, these guidelines were developed in the context of North American practices. Some recommendations may not be as applicable outside of North America, in areas where differences in available antibiotics, in the predominant pathogens, and/or in health care–associated economic conditions exist. Regardless of venue, clinical vigilance and immediate treatment are the universal keys to managing neutropenic patients with fever and/or infection.

False-positive serum and bronchoalveolar lavage Aspergillus galactomannan assays caused by different antibiotics

Our objective was to identify false-positive serum and bronchoalveolar lavage (BAL) fluid galactomannan (GM) tests caused by various antibiotics commonly used in general practice. Serum and BAL samples from patients who did not have the diagnostic criteria of invasive aspergillosis and received different antibiotics were prospectively analyzed for GM. Serum and BAL samples were also collected from patients who did not receive antibiotics. At the cut-off index of >or=0.5, false-positive serum results were found in patients who received amoxicillin-clavulanate, piperacillin-tazobactam, cefepime, and cefoperazone-sulbactam (26.7%, 58.3%, 14.3%, and 66.7%, respectively). Fungal colonization in BAL samples had a higher BAL GM than those without fungal colonization. In 71 patients who had a negative BAL culture for fungi, at the cut-off value of >or=1.0, false-positive BAL fluid results were found in patients who received amoxicillin-clavulanate (27.3%), piperacillin-tazobactam (50%), cefepime (16.7%), carbapenem (45.5%), and ceftriaxone (45.5%). False-positive serum and BAL GM assays were also detected in patients who did not receive any antibiotics. In summary, this study demonstrates the false-positive GM levels in serum and BAL caused by beta-lactam antibiotics that are commonly used in general practice. Physicians should be aware of this possible interference.

Aspergillosis: nosocomial or community-acquired?

Discrimination between nosocomial and community infections is important for investigation and prevention. Nosocomial and hospital-acquired infections require appropriate hospital control measures to avert additional cases. Nosocomial infections (NI) occur during hospitalization or are caused by microorganisms acquired during hospital stay. Such infections should not be evident when patients are admitted to the hospital. Furthermore, the definition of NI is based on epidemiological criteria, such as the time lapse between admission and onset, or microbiological criteria. This definition might be difficult to apply to invasive aspergillosis (IA) which often afflicts patients with severe immunosuppression or transplantation. Identification of the source may be difficult which could arise outside or inside the hospital. Another significant issue is the lack of valid and reproducible data on the incubation period. The incubation duration of IA is influenced by different individual or environmental determinants, including the severity of immunosuppression and air quality. The criteria of causality are also a means of discussing the contribution of hospital vs. community determinants of IA. The definition of nosocomial IA remains difficult. A better understanding of early events related to IA onset will help to prevent this disease for which the prognosis remains negative.

Invasive aspergillosis in pediatric patients

This case-based review examines the growing literature on critical issues related to the epidemiology, diagnosis, and treatment of pediatric invasive aspergillosis. Immunocompromised children are at heightened risk for invasive aspergillosis. Children at highest risk include those with new-onset or relapsed hematologic malignancy and recipients of allogeneic stem cell transplants. Additional risk factors in stem cell transplant recipients include impaired lymphocyte engraftment and graft-versus-host disease. Pediatric invasive aspergillosis is associated with a high mortality rate (generally >50%) and requires prompt diagnosis and treatment to prevent dissemination and death. Tools available for diagnosis include radiologic examinations (primarily computed tomography), the galactomannan assay, bronchoalveolar lavage, and tissue biopsy. Age-related differences in computed tomography and galactomannan assay results have been suggested. Recommended primary therapy for pediatric invasive aspergillosis is voriconazole (7 mg/kg IV q12 hours). Currently approved alternative therapies include liposomal amphotericin B, amphotericin B lipid complex, and caspofungin. Posaconazole and itraconazole are also possibilities, but there is no established pediatric dose for posaconazole, and itraconazole dosing is difficult in children. In patients who do not benefit from initial antifungal therapy, options include switching to another agent with a different mechanism of action or combination therapy. Further research is required to better establish optimal approaches to the management of pediatric patients with invasive aspergillosis recalcitrant to initial primary therapy.

High Levels of beta-D-glucan in immunocompromised children with proven invasive fungal disease

The plasmatic levels of 1,3-beta-d-glucan (BDG) were >523 pg/ml in 4 children, 2 low-birth-weight neonates and 2 stem cell transplant recipients, with the following invasive fungal diseases (IFD) proven apart from this BDG test: 3 cases of Candida parapsilosis candidemias and 1 case of disseminated aspergillosis. The BDG test may be useful for identification of IFD in pediatrics.

Detection of Aspergillus fumigatus in a rat model of invasive pulmonary aspergillosis by real-time nucleic acid sequence-based amplification

Rapid and sensitive detection of Aspergillus from clinical samples may facilitate the early diagnosis of invasive pulmonary aspergillosis (IPA). A real-time nucleic acid sequence-based amplification (NASBA) method was investigated by use of an inhalational rat model of IPA. Immunosuppressed male Sprague-Dawley rats were exposed to Aspergillus fumigatus spores for an hour in an aerosol chamber. Bronchoalveolar lavage (BAL) fluid, lung tissues, and whole blood were collected from five infected rats at 1, 24, 48, 72, and 96 h postinfection and five uninfected rats at the end of the experiment. Total nucleic acid (TNA) was extracted on an easyMAG instrument. A primer-molecular beacon set targeting 28S rRNA was designed to detect Aspergillus spp. The results were compared to those of quantitative PCR (qPCR) (18S rDNA) and quantitative culture. The analytical sensitivity of the real-time NASBA assay was <1 CFU/assay. A linear range of detection was demonstrated over 5 log units of conidia (10 to 10(5) spores). Both NASBA and qPCR showed a progressive increase in lung tissue burdens, while the CFU counts were stable over time. The fungal burdens in BAL fluid were more variable and not indicative of a progressive infection. The results of both real-time assays correlated well for both sample types (r = 0.869 and P < 0.0001 for lung tissue, r = 0.887 and P < 0.0001 for BAL fluid). For all whole-blood specimens, NASBA identified Aspergillus-positive samples in the group from which samples were collected at 72 h postinfection (three of five samples) and the group from which samples were collected at 96 h postinfection (five of five samples), but no positive results were obtained by culture or PCR. Real-time NASBA is highly sensitive and useful for the detection of Aspergillus in an experimental model of IPA.

Prospective monitoring for invasive aspergillosis using galactomannan and polymerase chain reaction in high risk pediatric patients

BACKGROUND

The diagnosis of invasive aspergillus remains a challenge in the care of high-risk patients. Outcomes are improved when invasive aspergillus is diagnosed early, prompting the initiation of appropriate antifungal therapy. We evaluated the utility of prospective monitoring for invasive aspergillosis (IA) using biomarkers such as serum galactomannan (GM) and/or blood polymerase chain reaction (PCR) in high-risk pediatric patients.

METHODS

Patients with high-risk leukemia (HRL) or allogenic hematopoietic cell transplant (HCT) recipients were prospectively monitored twice weekly for IA using GM and PCR for Aspergillus species.

RESULTS

Sixty-eight patients had collected >or=2 specimens. The 1086 specimens were collected; 627 from HRL (58%) and 459 (42%) from HCT recipients. Median specimens/patient was 11.0 (2 to 58), and median follow-up/patient was 98.5 days (14 to 437). Fifty-six percent of samples were obtained from patients receiving mold-active agents; 32% HRL and 89% HCT. There were no proven, 3 probable, and 20 possible episodes of IA. Thirteen specimens (1.2%) from 4 patients (5%) were GM+. None were positive by PCR.

CONCLUSIONS

The prospective use of GM and PCR in this high-risk pediatric population did not identify cases of proven IA. A high false positive rate was not detected. It is speculated that changes in clinical practice, such as early use of empiric and/or prophylactic mold-active agent and frequent imaging studies have impacted the epidemiology of IA. In a population with low incidence of IA, the use of these assays as a screening device on blood may not further enhance current outcomes.

Detection of sputum Aspergillus galactomannan for diagnosis of invasive pulmonary aspergillosis in haematological patients

We investigated the diagnostic utility of Aspergillus galactomannan (GM) in sputum for diagnosis of invasive pulmonary aspergillosis (IPA) in haematologic patients and compared the results with those of bronchial lavage fluid (BLF) and serum. Patients were classified into 4 groups using modified European Organization for Research and Treatment of Cancer criteria: group A, proven IPA; group B, probable IPA; group C, possible IPA; group D, others. Groups A and B were considered the IPA group (n = 6); group D was considered non-IPA group (n = 37); group C (n = 13) was equivocal for IPA. As a true negative control, sputa from patients with community-acquired pneumonia (CAP) without risk factors (group E, n = 22) were used. From the receiver-operating characteristic curves, the cut-off levels were determined as 1.2 in sputum, 0.5-1.3 in BLF and 0.5 in serum. The sensitivity and specificity of sputum, BLF and serum GM were 100 and 62.2%, 66.7 and 100%, and 83.3 and 81.1%, respectively. Twenty-two patients with CAP (group E) showed median GM levels in the sputa of 0.1 (range 0.0-1.0). Sputum GM is a useful non-invasive test for screening of IPA in haematological patients, and may also be useful for assessment of the risk of developing IPA.