Galactomannan Antigen Assay Research Articles

Is there an interest in systematic serum screening for aspergillosis in COVID-19 patients in a medical ward?

PurposeWe evaluated the interest of systematic screening of serum fungal markers in patients hospitalized in a medical ward. MethodsWe retrospectively analyzed all patients hospitalized in our infectious disease department from October 1st to October 31st, 2020 for COVID-19 without prior ICU admission, and for whom systematic screening of serum fungal markers was performed. ResultsThirty patients were included. The majority of patients received corticosteroids (96.7%). The galactomannan antigen assay was positive for 1/30 patients at D0, and 0/24, 0/16, 0/13 and 0/2 at D4, D7, D10 and D14 respectively. 1,3-ß-D-glucan was positive for 0/30, 1/24, 1/12, 0/12, 0/2 at D0, D4, D7, D10 and D14 respectively. No Aspergillus fumigatus PCR was positive. No cases of aspergillosis were retained. ConclusionOur study does not support the interest of systematic screening of fungal markers in immunocompetent patients with COVID-19 in a conventional unit.

Galactomannan Antigen Assay for the Diagnosis of Invasive Aspergillosis: A Study from a Tertiary Care Hospital of Central India

Invasive Aspergillosis (IA) is a severe and fatal infection, especially in immunocompromised patients. Galactomannan is a polysaccharide antigen present in the cell wall of Aspergillus species, which is secreted into the blood and other body fluids during hyphal growth. Therefore, detecting galactomannan antigen is very useful in diagnosing IA, along with clinical features and radiological findings. The study period was one year (January 2022 to December 2022). The data was collected retrospectively from the medical records and case sheets of all clinically suspected invasive aspergillosis patients. Galactomannan antigen assay was performed using an FDA-approved Platelia Aspergillus EIA test kit, and results were interpreted according to the manufacturer’s instructions (Cut off > 0.5). A total of 236 clinically suspected Invasive Aspergillosis cases were enrolled in the study. Galactomannan positivity was predominantly seen in patients aged 40 – 60 years, with male preponderance. Of 236 patients, 14.40% were immunocompromised, and 85.59% were immunocompetent. According to EORTC/MSG definitions, we got one proven IA case, 21 probable cases (8.89%), and nine (3.81%) possible cases. In immunocompetent individuals also, we observed 48.72% (115/236) galactomannan positivity, especially in old Pulmonary Tuberculosis (PTB) patients. Galactomannan positivity was higher in Broncho alveolar lavage (BAL) samples (n=70, 85.36%) than in serum samples (n=77, 46.67%). We found culture positivity of 14.06%, with Aspergillus fumigatus being the commonest isolate, followed by Aspergillus flavus. There is increased positivity of galactomannan in BAL samples compared to serum; hence BAL is a better specimen for diagnosis of Invasive Pulmonary Aspergillosis (IPA).

Retrospective Multicenter Evaluation of the VirClia Galactomannan Antigen Assay for the Diagnosis of Pulmonary Aspergillosis with Bronchoalveolar Lavage Fluid Samples from Patients with Hematological Disease.

Galactomannan (GM) testing of bronchoalveolar lavage (BAL) fluid samples has become an essential tool to diagnose invasive pulmonary aspergillosis (IPA) and is part of diagnostic guidelines. Enzyme-linked immunosorbent assays (ELISAs) (enzyme immunoassays [EIAs]) are commonly used, but they have a long turnaround time. In this study, we evaluated the performance of an automated chemiluminescence immunoassay (CLIA) with BAL fluid samples. This was a multicenter retrospective study in the Netherlands and Belgium. BAL fluid samples were collected from patients with underlying hematological diseases with a suspected invasive fungal infection. Diagnosis of IPA was based on the 2020 European Organisation for Research and Treatment of Cancer (EORTC)/Mycoses Study Group Education and Research Consortium (MSGERC) consensus definitions. GM results were reported as optical density index (ODI) values. ODI cutoff values for positive results that were evaluated were 0.5, 0.8, and 1.0 for the EIA and 0.16, 0.18, and 0.20 for the CLIA. Probable IPA cases were compared with two control groups, one with no evidence of IPA and another with no IPA or possible IPA. Qualitative agreement was analyzed using Cohen's κ, and quantitative agreement was analyzed by Spearman's correlation. We analyzed 141 BAL fluid samples from 141 patients; 66 patients (47%) had probable IPA, and 56 cases remained probable IPA when the EIA GM result was excluded as a criterion, because they also had positive culture and/or duplicate positive PCR results. Sixty-three patients (45%) had possible IPA and 12 (8%) had no IPA. The sensitivity and specificity of the two tests were quite comparable, and the overall qualitative agreement between EIA and CLIA results was 81 to 89%. The correlation of the actual CLIA and EIA values was strong at 0.72 (95% confidence interval, 0.63 to 0.80). CLIA has similar performance, compared to the gold-standard EIA, with the benefits of faster turnaround because batching is not required. Therefore, CLIA can be used as an alternative GM assay for BAL fluid samples.

The role of galactomannan test results in the diagnosis of pediatric invasive aspergillosis

Background Invasive aspergillosis (IA) is an important cause of morbidity and mortality in immunosuppressed children. Early detection of the infection can improve prognosis in this patient population. Objectives To investigate the utility of Aspergillus galactomannan antigen assay (GM-EIA) as a diagnostic tool for IA in at-risk paediatric patients. Patients/Methods For the study, 659 GM-EIA results from 59 patients diagnosed with IA and 3368 GM-EIA results from 351 subjects without evidence for IA (controls) were reviewed retrospectively. Three cut-off values (i.e. ≥0.5, ≥1, ≥1.5) were specified to determine GM-EIA positivity. Results The median age was 6.3 years for boys and 14.5 years for girls. There was a significant difference between the girls and boys in terms of age (p < 0.01). For proven/probable/possible IA patients, sensitivity of 67.8% and specificity of 59.8% were detected when the ≥0.5 cut-off value was used for GM-EIA-positivity. The specificity increased to 80% at the cut-off of ≥1 and to 88% at the cut-off of ≥1.5. False positivity rates were 9.14, 3, and 1.45% at the ≥0.5, ≥1 and ≥1.5 cut-offs respectively. In the proven/probable IA group, sensitivity and negative predictive values were 86.9 and 97.2% at the ≥0.5 cut-off, 85.7 and 97.9%, at the ≥1 cut-off and 84.2 and 98.1% at ≥1.5 cut-off respectively. The positive likelihood ratio was 7.57 and the odds ratio was 42.67 at ≥1.5 cut-off. Conclusion The GM-EIA may be used for both screening and diagnostic purposes in paediatric patients using a cut-off value of ≥1.5 for GM-EIA positivity.

Early diagnosis of aspergillosis in asthmatic and rheumatoid arthritis patients by Aspergillus galactomannan antigen assay: a case-control study in Karbala providence

Objective Aspergillosis is an opportunistic systemic infection caused by members of Aspergillus spp. in various parts of the human body. Chronic diseases such as rheumatoid arthritis (RA) and asthma may encourage the development of aspergillosis under specific conditions. Thus, aspergillosis was investigated in patients with RA and asthma based on detection of galactomannan antigen. Methods A case-control study was performed to involve 184 subjects, distributing in four groups: 55 patients with RA, 54 with asthma, 27 with both RA and asthma, and 48 healthy individuals. Serum was collected from involved subjects for detection of human Aspergillus galactomannan by ELISA. The optical density index (ODI) at cutoff <0.5 was used to determine the infection. Results Aspergillosis was more frequently diagnosed in females with RA and both RA and asthma in opposite to the males. It also was found in most common in middle-aged subjects. There was no significant difference in measurement of GM between all patient groups and healthy individuals. Conclusion Aspergillosis can develop in either immunocompetent or immunocompromised individuals. Patients with either RA or RA and asthma are more susceptible to acquired aspergillosis than those with only one disease. Application of GM for diagnosis of aspergillosis may show a nonsignificant results when it uses alone and needs other investigation tests.

Effect of an oral probiotic nutraceutical containing Aspergillus-derived ingredients on a serum and urine galactomannan antigen assay in dogs

A commercial Aspergillus galactomannan antigen (GMA) enzyme linked immunosorbent assay (ELISA) is used to support a diagnosis of systemic aspergillosis in dogs. In human patients, false positive results have been associated with administration of medications derived from molds. We sought to determine the effect of administration of a commercially available oral probiotic nutraceutical that contained Aspergillus-derived ingredients on serum and urine Aspergillus GMA levels in dogs by conducting a prospective, cross-over study. Galactomannan index (GMI) was measured on the solubilized probiotic nutraceutical and was positive (GMI ≥ 0.5) with a mean of 7.91. Serum and urine galactomannan indices were measured in 10 healthy dogs before (day 0) and after 1 week (day 7) of probiotic nutraceutical administration, then again 2 weeks after the probiotic nutraceutical was discontinued (day 21).Median (range) serum GMI were 0.19 (0.08–0.62), 0.22 (0.07–1.15) and 0.17 (0.14–0.63) at day 0, 7 and 21, respectively. Two of 10 dogs developed positive GMI (≥0.5) results after probiotic nutraceutical administration; however, no significant changes were noted over the study period. Median (range) urine GMI results were 0.06 (0.04–0.22), 0.07 (0.05–0.41) and 0.06 (0.03–0.16) at day 0, 7 and 21, respectively. A trend towards an increase urine GMI was noted between day 0 and 7 (P = 0.18), and decrease was noted between day 7 and 21 (P = 0.09). Administration of probiotics containing Aspergillus-derived ingredients to dogs did not reliably result in elevated Aspergillus GMA levels.

Epidemiology, utilisation of healthcare resources and outcome of invasive fungal diseases following paediatric allogeneic haematopoietic stem cell transplantation.

Epidemiology and management practices of invasive fungal diseases (IFD) after allogeneic haematopoietic stem cell transplantation (HSCT) are a subject of constant change. We investigated the contemporary incidence, diagnostics, antifungal management and outcome at a major paediatric transplant centre in Germany. The single-centre retrospective observational study included all paediatric allogeneic HSCT patients (pts) transplanted between 2005 and 2015. Patient-related data were assessed up to 365days post-transplant. The primary endpoint was the incidence of possible, probable and proven IFDs. Secondary endpoints included diagnostics and antifungal treatment; analysis of risk factors; and overall survival with the last follow-up in January 2017. A total of 221 first (196), second (21) or third (4) procedures were performed in 200 pts (median age: 9years, range, 0.5-22) for leukaemia/lymphoma (149) and non-malignant disorders (72). Prophylaxis was administered in 208 HSCT procedures (94%; fluconazole, 116, mould-active agents, 92). At least one computed tomography scan of the chest was performed in 146, and at least one galactomannan antigen assay in 60 procedures. There were 15 cases of proven (candidemia, 4; aspergillosis, 4) or probable (aspergillosis, 7) IFDs, accounting for an incidence rate of 6.8%. Overall mortality at last follow-up was 30%; the occurrence of proven/probable IFDs was associated with a reduced survival probability (P<.001). Morbidity and mortality from IFDs at our institution were consistent with data reported from other centres. Utilisation of healthcare resources for prevention, diagnosis and management of IFDs was considerable.

Native valve dual pathogen endocarditis caused by Burkholderia cepacia and Aspergillus flavus – a case report

Introduction Infective endocarditis (IE) is an important clinical condition with significant morbidity and mortality among the affected population. A single etiological agent is identifiable in more than 90 % of the cases, however, polymicrobial endocarditis (PE) is a rare find, with a poor clinical outcome. Here we report a case of native valve dual pathogen endocarditis caused by Burkholderia cepacia and Aspergillus flavus in an immunocompetent individual. It is among unique occurrences of simultaneous bacterial and fungal etiology in IE.Case presentation A 30-year-old male was admitted to a cardiology institute with complaints of low grade intermittent fever and progressive shortness of breath for last two months. He was a known case of rheumatic heart disease and had suffered an episode of IE three years ago. On the basis of clinical presentation and the results of radiological investigations, a diagnosis of infective endocarditis was made. Paired blood samples for culture and sensitivity, sampled before the commencement of antimicrobial therapy, yielded growth of Burkholderia cepacia which was highly drug resistant. Sensitivity results-directed therapy consisting of tablet Trimethoprim–Sulfamethoxazole, two double-strength tablets 12 hourly, and Meropenem, 1 g IV every 8 h, was commenced. Despite mild relief of fever intensity, overall clinical condition did not improve and double valve replacement therapy was carried out. Excised valves were sent for microbiological analysis. Burkholderia cepacia was grown on tissue culture with a similar antibiogram to that previously reported from the blood culture of this patient. Direct microscopy of section of valvular tissue with 10 % KOH revealed abundant fungal hyphae. Patient serum galactomannan antigen assay was also positive. Histopathological examination of vegetations also revealed hyphae typical of species of the genus Aspergillus. The patient was successfully treated with meropenem, trimethoprim–sulfamethoxazole and voriconazole.Conclusion The hallmark of successful treatment in this case was exact identification of pathogens, antibiogram-directed therapy and good liaison between laboratory experts and treating clinicians.

Role of bronchoalveolar lavage in the diagnosis of pulmonary infiltrates in immunocompromised patients.

To describe the role of bronchoalveolar lavage (BAL) in the evaluation of pulmonary disease in immunocompromised patients. Recent discoveries in this field are largely in two areas: the array of diagnostic testing performed on BAL fluid and technical details that can enhance the yield from this procedure. Regarding diagnostic testing, the addition of new assays, including Aspergillus galactomannan antigen assay, respiratory viral panels, and Pneumocystis jirovecii PCR, has improved the diagnostic yield of BAL over conventional cultures and stains. To improve the diagnostic yield of the procedure itself, it should be done early in the clinical course, with the BAL in the anatomic area most affected, and with a preprocedural computed tomography of the chest to properly plan the procedure. Bronchoscopic evaluation with BAL can provide important diagnostic information in immunocompromised patients with pulmonary diseases and should be routinely performed when clinically indicated and able to be completed safely.

Characterization of the Aspergillus fumigatus chitosanase CsnB and evaluation of its potential use in serological diagnostics

Aspergillus fumigatus is currently the major air-borne fungal pathogen as its asexual spores are distributed through the air. In severely immunocompromised patients, inhalation of these conidia can result in life-threatening infections. Invasive Aspergillosis, a major Aspergillus-associated disease, is associated with a high mortality reflecting short-comings in diagnostics and therapy. Current diagnostics largely rely on the serological detection of the galactomannan antigen. Detection of circulating antibodies is an alternative approach. In this study, we have characterized the chitosanase CsnB, a protein that was previously shown to be a major secreted A. fumigatus antigen and therefore a potential target for antibody-based diagnostics.To analyze the biological function of CsnB we have deleted the csnB gene and generated CsnB-specific antibodies. We found that A. fumigatus is able to grow on chitosan in a CsnB-dependent manner. During growth on chitosan elevated levels of CsnB are found in the supernatants indicating that chitosan triggers enhanced CsnB production. Unexpectedly we have found a similar activity for tartrate.Using recombinant proteins we analyzed antibody responses in patients at risk to develop invasive aspergillosis. We focussed this study on two antigens: CsnB and for comparison mitogillin, a secreted A. fumigatus ribotoxin. IgG responses were found to both proteins, but elevated antibody levels to CsnB and/or mitogillin showed no correlation to the results of the galactomannan antigen assay or clinical signs that are characteristic for fungal infections.

Intérêt du dosage de l’antigène galactomannane dans le diagnostic et le suivi de l’histoplasmose disséminée à Histoplasma capsulatum var. duboisii au cours du VIH : enseignement à partir d’un cas clinique

The diagnosis of histoplasmosis due to Histoplasma capsulatum var capsulatum is based on a direct examination identifying encapsulated yeast with narrow-based budding. Galactomannan antigenemia facilitates diagnosis, as well as the monitoring of patients receiving treatment. The case of a HIV-positive patient from Congo-Brazzaville with a disseminated form of African histoplasmosis highlighted the positive galactomannan antigen in this disease due to Histoplasma capsulatum var duboisii. Galactomannan antigenemia remained high with a very slow decrease during antifungal therapy and slow regression of clinical lesions. African histoplasmosis is a rare disease that is difficult to diagnose and rarely described in immunocompromised patients, in whom differential diagnosis can be common. This observation underlines the importance of the galactomannan antigen assay in patients who have travelled to endemic areas. As in the case of Histoplasma capsulatum var capsulatum, the positivity of the Aspergillus galactomannan antigen is very useful in the diagnosis and monitoring of African histoplasmosis.

Galactomannan antigen assay from bronchoalveolar lavage fluid in diagnosis of invasive pulmonary aspergillosis in intensive care units patients

Background:Invasive pulmonary aspergillosis (IPA) is an important infection in critically ill patients including patients of intensive care units (ICU). Different diagnostic tools are available and since its mortality is high, it is vital to start the antifungal therapy as soon as possible. Knowing the epidemiology of this disease in each ICU and area will help to better and more rapid management of such patients. The aim of this study is to determine the frequency of IPA based on the level of galactomannan in bronchoalveolar lavage fluid in ICU of Al-Zahra hospital, Isfahan, Iran.Materials and Methods:This was a cross sectional study, which was conducted in Al-Zahra hospital, Isfahan, Iran, between 2010 to 2011. The study population was all the patients admitted to ICU and were suspected to have invasive Aspergillus spp pneumonia. The level of galactomannan in bronchoalveolar lavage was measured and demographic data were gathered by the questionnaire.Results:The frequency of IPA in this study was calculated as 2.43% while galactomannan level in bronchoalveolar lavage fluid of this patient (2.50) was significantly higher than others (0.03 ± 0.02).Conclusion:Larger studies are required to determine the exact frequency of IPA and the best antifungal therapy for it.

Sensitivity and Specificity of a Blood and Urine Galactomannan Antigen Assay for Diagnosis of Systemic Aspergillosis in Dogs

Diagnosis of canine systemic aspergillosis requires fungal culture from a sterile site, or confirmatory histopathology from a nonsterile site. Invasive specimen collection techniques may be necessary. To evaluate the sensitivity and specificity of a serum and urine Aspergillus galactomannan antigen (GMA) ELISA assay for diagnosis of systemic aspergillosis in dogs. Multicenter study. Thirteen dogs with systemic aspergillosis and 89 dogs with other diseases. Thirty-seven of the 89 dogs had signs that resembled those of systemic aspergillosis and 52 dogs were not suspected to have aspergillosis. The GMA ELISA was performed on serum specimens from all dogs and urine specimens from 67 dogs. Galactomannan indices (GMI)≥0.5 were considered positive. Results for dogs in each group were compared. The sensitivity and specificity of the assay for serum were 92 and 86%, respectively, and for urine were 88 and 92%, respectively. False negatives were seen only in dogs with localized pulmonary aspergillosis. Use of a cutoff GMI of 1.5 increased specificity to 93% for both serum and urine without loss of sensitivity for diagnosis of disseminated infection. High-level false positives (>1.5) occurred in dogs with other systemic mycoses and those treated with Plasmalyte. Serum and urine Aspergillus GMA ELISA is a noninvasive, sensitive, and specific test for the diagnosis of disseminated aspergillosis in dogs when a cutoff GMI of ≥1.5 is used.

Fungal infections after lung transplantation

Lung transplant's Achilles heel is chronic rejection. This is the reason why high immunosuppression is used, which leads to the development of infections. Fungal infections are a great obstacle in lung transplant patients' progress, not only because of their impact on patient survival, but also because fungal infections indirectly have an influence on the graft's progress. This review highlights the changing spectrum of invasive fungal infections as well as the most recent developments in diagnosis, prophylaxis, treatment and monitoring of lung transplantation. Fungal infections have a bimodal presentation: early onset, in relation to difficult postsurgeries and prior colonizations, and late onset, primarily in relation to chronic rejection and terminal renal insufficiency. The clinical impact of non-Aspergillus moulds is still unknown. Recent efforts have focused on nonculture-based methods to establish a rapid diagnosis. However, multicentre studies are needed to establish the diagnostic value of galactomannan antigen assay in invasive aspergillosis in lung transplantation. In addition, studies of the sensitivity and specificity of PCR assays are required to establish their diagnostic value. Unfortunately, only some advances in the diagnosis of aspergillosis have been achieved. Prophylaxis should be tailored according to the different individual patient's risk status. Combined treatments, including surgical therapy, may be useful in some patients.