Serum Galactomannan Research Articles

2047. Study of Molecular epidemiology, risk factor analysis and comparison of diagnostic methods for rapid diagnosis of fungal pneumonia in critically ill cirrhotics

BackgroundLiver cirrhosis causes immune dysregulation and increased susceptibility to fungal infections. We studiede risk factors, molecular epidemiology and compared the rapid diagnostic methods and biomarkers for fungal pneumonia in critically ill cirrhoticsMethodsSingle-center, prospective cohort study of 50 critically ill cirrhotics with fungal pneumonia between January and September 2017. Comparative analysis of culture, real-time PCR and biomarkers; Bronchoalveolar lavage and serum galactomannan, serum procalcitonin were measured by ELISA and chemiluminescence assay on Days 1, 3, 7. Final outcome were mortality within 1 month after diagnosis or discharge. Genotyping of clinical and air sampling Aspergillus isolates was doneResults Aspergillus flavus was most common species (34/50, 68%). Risk factors were, neutropenia (P 0.03), steroids prior to ICU admission (P 0.02), prolonged hospitalizations >21 days (P 0.05). Culture positivity was 80%. Culture was not inferior to real-time PCR for diagnosis of fungal pneumonia. BAL Galactomannan was early prognostic marker with median rise above >1 index value on Day 1. Median PCT level was higher from Day 1 in the fungal pneumonia nonsurvivor group (3.29 vs. 0.8 ng/mL) with higher 30-day mortality (72%). Higher PCT was associated with bacterial co-infection (48%), antibiotic(74%) and antifungal therapy and renal failure and mortality. Cinical isolates from patients matched those recovered from air in two clusters.ConclusionFungal pneumonia complicates cirrhotics with neutropenia, prolonged hospitalization and steroids as risk factors. Aspergillus species predominate as in Asian epidemiology. Culture methods are reliable and combination of molecular test with BAL galactomannan is useful for rapid diagnosis. SerumPCT is raised in patients with fungal pneumonia and associated with higher mortality. In our study the baseline PCT at admission to ICU was higher in nonsurvivor group, levels on D3 and D7 were persistantly higher. High serum procalcitonin level is an independent prognostic biomarker of mortality risk in fungal pneumonia. Genetic relatedness of clinical and environmental sample necessitates infection control measures to prevent invasive aspergillosis in high-risk patients.Disclosures All authors: No reported disclosures.

Utility of serum galactomannan antigen testing combined with chest computed tomography for early diagnosis of invasive pulmonary aspergillosis in patients with hematological malignancies with febrile neutropenia after antifungal drug treatment.

ObjectiveTo investigate the value of serum galactomannan antigen (GM) testing combined with chest computed tomography (CT) as a noninvasive method for early diagnosis of invasive pulmonary aspergillosis (IPA) in patients with hematological malignancies with febrile neutropenia after antifungal drug treatment.MethodsWe retrospectively analyzed the data of 376 patients with febrile neutropenia from January 2015 to August 2017. All patients were given broad-spectrum antibiotics and divided into the control group (effective antibiotic treatment, no antifungal drugs given) and the observational group (ineffective antibiotic treatment, antifungal drugs given). The serum GM testing, chest CT, and microbiological examination findings were compared between the two groups.ResultsThe false-positive rates of GM testing for IPA in the control and observational groups were 4.04% and 8.65%, respectively, and the false-negative rates in the two groups were 1.10% and 9.62%, respectively. Sixty-five patients in the observational group and 11 in the control group had typical features of CT imaging.ConclusionClinical weekly screening of serum GM and chest CT may be an effective combined approach to the early diagnosis of IPA in patients with febrile neutropenia, even if they have undergone antifungal treatment.

The role of galactomannan Aspergillus antigen in diagnosing acute invasive fungal sinusitis.

Pathologic diagnosis remains the gold standard for final diagnosis of acute invasive fungal sinusitis (AIFS); however, other less invasive tests could suggest the presence of AIFS in at-risk populations where early diagnosis is crucial. Serum galactomannan Aspergillus antigen has been shown to correlate with a diagnosis of invasive pulmonary aspergillosis; however, it has not adequately been evaluated in regard to AIFS. The objective of this study is to evaluate the statistical relevance of galactomannan in predicting diagnosis of AIFS. This study was a retrospective review of pathologic records using Co-Path from 2006 to 2017, incorporating 2 separate searches with designated criteria identifying patients who received pathologic evaluation for invasive fungal sinusitis. Electronic medical records were subsequently reviewed. After exclusions isolating at-risk populations and removing duplications, 78 cases were reviewed using the indicated search criteria. Of these, 38 met further criteria of having had both pathologic evaluation and galactomannan analysis. Statistical variables were assessed, as well as all-cause mortality. Peak and closest galactomannan levels were evaluated. Overall, galactomannan had a sensitivity of 44.8% (95% confidence interval [CI], 26.5% to 64.3%), specificity of 100% (95% CI, 66.4% to 100%), positive predictive value of 100% (95% CI, 74.3% to 100%), and negative predictive value of 36% (95% CI, 18.0% to 57.5%). No significant association was observed in galactomannan status and mortality in this patient population. Positive serum galactomannan can be an indication of AIFS in patients with a high clinical suspicion. In our study, a positive galactomannan always correlated with a positive pathologic diagnosis. However, given its low sensitivity, one must use caution in relying on galactomannan as a screening tool in diagnosis of AIFS.

Baseline serum Aspergillus galactomannan index in patients with hematologic malignancy and culture-documented invasive pulmonary aspergillosis: is there a difference among Aspergillus species?

It is unclear whether differences exist in baseline serum galactomannan (sGM) in patients with hematologic malignancies and invasive pulmonary aspergillosis (IPA) caused by non-fumigatus Aspergillus species vs Aspergillus fumigatus. We found no differences in baseline sGM positivity rates, median sGM levels, and 42-day mortality in 72 such patients (Aspergillus fumigatus in 43 and non-fumigatus Aspergillus in 29).

Rash in an Extremely Low Birth Weight Infant

Primary cutaneous aspergillosis (PCA) is one of several invasive fungal infections that have increased in incidence in the last four decades. We present a case of an extremely low birth weight infant born at 24 weeks gestation diagnosed with cutaneous aspergillosis, highlighting the risk factors and clinical findings associated with neonatal PCA. Additionally, we discuss use of serum galactomannan testing as well as combination amphotericin B and voriconazole therapy.

Galactomannan antigenemia as a biomarker for therapeutic response of invasive aspergillosis: implications for clinical trial design and patient care

ABSTRACTIntroduction: Clinical trials for invasive pulmonary aspergillosis, a potentially lethal mold infection, are complex investigations that require protracted time and extensive resources, delaying the development of new antifungal agents for this important disease.Areas covered: In this paper, the authors examine a novel approach to study invasive pulmonary aspergillosis in humans, with a focus on the potentials and pitfalls of surrogate end points such as galactomannan antigenemia to evaluate therapeutic response to novel compounds.Expert commentary: The authors believe the use of serum galactomannan as a primary end point in clinical trials may allow for development studies that could be accomplished with fewer resources. It is widely appreciated that serum galactomannan values strongly correlate with outcome of invasive aspergillosis in patients with hematologic cancer and may be applicable to other at-risk patient populations.

Breakthrough invasive aspergillosis and diagnostic accuracy of serum galactomannan enzyme immune assay during acute myeloid leukemia induction chemotherapy with posaconazole prophylaxis.

Posaconazole prophylaxis has demonstrated efficacy in the prevention of invasive aspergillosis during prolonged neutropenia following acute myeloid leukemia induction chemotherapy. Antifungal treatment decreases serum galactomannan enzyme immunoassay diagnostic accuracy that could delay the diagnosis and treatment.We retrospectively studied patients with acute myeloid leukemia who underwent intensive chemotherapy and antifungal prophylaxis by posaconazole oral suspension. Clinical, radiological, microbiological features and treatment response of patients with invasive aspergillosis that occurred despite posaconazole prophylaxis were analyzed. Diagnostic accuracy of serum galactomannan assay according to posaconazole plasma concentrations has been performed.A total of 288 patients with acute myeloid leukemia, treated by induction chemotherapy, who received posaconazole prophylaxis for more than five days were included in the present study. The incidence of invasive aspergillosis was 8% with 12 (4.2%), 8 (2.8%) and 3 (1%), possible, probable and proven invasive aspergillosis, respectively. Posaconazole plasma concentration was available for 258 patients. Median duration of posaconazole treatment was 17 days, and median posaconazole plasma concentration was 0.5 mg/L. None of patients with invasive aspergillosis and posaconazole concentration ≥ 0.5 mg/L had a serum galactomannan positive test. Sensitivity of serum galactomannan assay to detect probable and proven invasive aspergillosis was 81.8%. Decreasing the cut-off value for serum galactomannan optical density index from 0.5 to 0.3 increased sensitivity to 90.9%.In a homogenous cohort of acute myeloid leukemia patients during induction chemotherapy, increasing the posaconazole concentration decreases the sensitivity of serum galactomannan assay.

Invasive mould disease in haematologic patients: comparison between fusariosis and aspergillosis

ObjectivesTo compare the epidemiology, clinical presentation, diagnosis, treatment, and outcome of haematologic patients with invasive aspergillosis (IA) or invasive fusariosis (IF). MethodsWe retrospectively reviewed the charts of 36 patients with IA and 26 with IF diagnosed between 2006 and 2017 in haematologic patients, and compared baseline characteristics, coexisting exposures, clinical manifestations, treatment, and the outcome. ResultsFever was more frequent in IF (96.2% vs. 63.9%, p 0.003), whereas pneumonia (88.9% vs. 50.0%, p 0.001) and sinusitis (63.9% vs. 38.5%, p 0.048) were more frequent in IA. Skin lesions and positive blood cultures occurred exclusively in patients with IF. Among patients with pneumonia, the halo sign was more frequent in IA (62.5% vs. 23.1%, p 0.02). Serum galactomannan was positive in 88.6% of patients with IA and in 73.3% with IF (p 0.18), with no differences in the median number of positive tests and galactomannan values. Positive serum galactomannan plus lung infiltrates was the predominant clinical presentation in IA and occurred in four of 13 patients with IF and lung involvement. The 30-day survival was 77.7% in IA and 46.1% in IF (p 0.01). ConclusionsIA and IF share the same epidemiologic scenario but different clinical presentations in the majority of cases, with disease in the airways in IA, and fever, metastatic skin lesions, and positive blood cultures in IF. However, a substantial proportion of patients with IF present with a clinical picture similar to IA, with fever, lung infiltrates, and positive serum galactomannan.

Serum galactomannan antigen as a prognostic and diagnostic marker for invasive aspergillosis in heterogeneous medicine ICU patient population.

ObjectiveThis study was conducted to get a complete clinical and mycological picture of invasive aspergillosis (IA) in respiratory medicine ICU of a tertiary care hospital.PatientsFrom the cohort of 235 patients only one had proven IA. Based on AspICU algorithm, 21 had putative IA (8.9%), 12 were colonised (5.1%).ResultsAdjusting the confounding factors, significant risk factors for IA were chronic obstructive pulmonary disease (COPD), temperature of ≥38°C, pneumonia and acute respiratory distress syndrome (ARDS). The best predictor of IA was AspICU algorithm (AUC, 1) followed by serum galactomannan antigen (GM) cut-off (≥1.24) calculated based on AspICU algorithm (AUC, 0.822). For 37% of patients, IA diagnoses was made earlier with serum GM than radiology. There were 70/235 (29.8%) deaths within 30 days of enrolment in the study. Aspergillus culture positivity (34/235, 14.5%) was associated with very high mortality (27/34, 79.4%), (p<0.05). The best predictor of mortality was GM cut-off (≥1.24) calculated based on AspICU algorithm (AUC, 0.835).ConclusionThis study imparts the focus on relatively underestimated Aspergillus infections prevalent in ICUs. The AspICU algorithm was found to be useful over others for IA diagnosis. The prognostic usefulness of serum GM antigen detection test highlighted overlooking the same may not be rewarding for the outcome of IA suspected ICU subpopulation.

Urine Antigen Detection as an Aid to Diagnose Invasive Aspergillosis.

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

Galactomannan, a Surrogate Marker for Outcome in Invasive Aspergillosis: Finally Coming of Age.

Detection of galactomannan has become widely available for diagnosing invasive aspergillosis. The test characteristics, using the Platelia™ enzyme-immunoassay, have been well described. This assay could potentially also be useful for the early evaluation of the efficacy of antifungal therapy and for predicting the outcome in terms of response and survival. In this systematic review, we assessed the available evidence for the use of serum galactomannan at baseline as a prognostic marker, and the predictive value of serum galactomannan kinetics after initiation of antifungal therapy. Overall, serum galactomannan at baseline and galactomannan kinetics appear to be good predictors of therapy response and survival. However, breakpoints for predicting therapy failure and validation in different patient populations are still lacking.

Serum (1\u21923)-\u03b2-D-glucan and galactomannan levels in patients with cystic fibrosis: a retrospective cohort study

BackgroundAspergillus fumigatus is frequently encountered in sputum samples of patients with cystic fibrosis (CF), which traditionally has been interpreted as saprophytic airway colonization. However, this mere bystander role has been challenged by recent data. There is now evidence that Aspergillus fumigatus accelerates the decline of pulmonary function.(1→3)-β-D-glucan (BDG) and galactomannan (GM) are highly sensitive fungal biomarkers that are used to diagnose invasive fungal disease. However, their diagnostic value in CF patients is largely unknown.MethodsWe conducted a retrospective cohort study on 104 CF patients to determine whether serum BDG and GM levels correlate with parameters such as Aspergillus-positive sputum cultures and lung function.ResultsAspergillus fumigatus was persistently detected in 22 of the 104 CF patients (21%). Mean serum BDG and GM levels in the Aspergillus-positive patients were significantly higher than in those without persistent Aspergillus detection (89 versus 40 pg/ml [p = 0.022] and 0.30 versus 0.15 ODI [p = 0.013], respectively). 27 and 7 patients had elevated BDG (≥ 60 pg/ml) or GM levels (> 0.5 ODI), respectivly. BDG and GM levels showed a significant correlation (p = 0.004). Patients with increased serum concentrations of BDG were more frequently Aspergillus-positive (40.7 versus 14.3%, p = 0.004) and had a significantly lower forced expiratory volume in one second (FEV1) than patients with a normal BDG (61.6 versus 77.1%, p = 0.007). In the multivariate analysis, BDG but not GM or the growth of A. fumigatus, proved to be an independent predictor for the FEV1.ConclusionsCF patients with persistent Aspergillus detection have elevated BDG and GM levels which ranged between healthy and invasively infected patients. Serum BDG may be superior to GM and fungal culture in predicting an impaired lung function in CF patients.

Microbiologic Diagnostic Workup of Acute Respiratory Failure with Pulmonary Infiltrates after Allogeneic Hematopoietic Stem Cell Transplantation: Findings in the Era of Molecular- and Biomarker-Based Assays

Allogeneic hematopoietic stem cell transplantation (HSCT) recipients frequently develop acute respiratory failure (ARF) with pulmonary infiltrates. Molecular- and biomarker-based assays enhance pathogen detection, but data on their yield in this population are scarce. This was a retrospective single-center study of 156 consecutive HSCT recipients admitted to the intensive care unit (ICU) between May 2013 and July 2017. Findings from a microbiologic diagnostic workup using currently available methods on bronchoalveolar lavage (BAL) and blood samples from 66 patients (age, 58 years [range, 45 to 64]; HSCT to ICU, 176 days [range, 85 to 407]) with ARF and pulmonary infiltrates were analyzed. In 47 patients (71%) a causative pathogen was identified (fungal, n = 28; viral, n = 26; bacterial, n = 18). Polymicrobial findings involving several pathogen groups occurred in 20 patients (30%). Culture (12/16, 75%), galactomannan (13/15, 87%), and Aspergillus-PCR (8/9, 89%) from BAL but not serum galactomannan (6/14, 43%) helped to diagnose invasive aspergillosis (n = 16, 24%). Aspergillus-PCR detected azole resistance in 2 cases. Mucorales was found in 7 patients (11%; BAL culture, n = 6; Mucorales-PCR, n = 1). Patients with identified pathogens had higher Simplified Acute Physiology Score II scores (P = .049) and inferior ICU survival (6% versus 37%, P < .01), which largely related to the presence of an invasive fungal infection. Eight patients (12%) had 1 or more viruses with uncertain lung pathogenicity as the sole microbiologic finding. A diagnostic microbiologic workup incorporating molecular- and biomarker-based assays identified pathogens in most HSCT recipients with ARF and pulmonary infiltrates admitted to the ICU. Implications of polymicrobial infection and pathogen patterns in these patients warrant further investigation.

Diagnosis and management of Aspergillus diseases: executive summary of the 2017 ESCMID-ECMM-ERS guideline

The European Society for Clinical Microbiology and Infectious Diseases, the European Confederation of Medical Mycology and the European Respiratory Society Joint Clinical Guidelines focus on diagnosis and management of aspergillosis. Of the numerous recommendations, a few are summarized here. Chest computed tomography as well as bronchoscopy with bronchoalveolar lavage (BAL) in patients with suspicion of pulmonary invasive aspergillosis (IA) are strongly recommended. For diagnosis, direct microscopy, preferably using optical brighteners, histopathology and culture are strongly recommended. Serum and BAL galactomannan measures are recommended as markers for the diagnosis of IA. PCR should be considered in conjunction with other diagnostic tests. Pathogen identification to species complex level is strongly recommended for all clinically relevant Aspergillus isolates; antifungal susceptibility testing should be performed in patients with invasive disease in regions with resistance found in contemporary surveillance programmes. Isavuconazole and voriconazole are the preferred agents for first-line treatment of pulmonary IA, whereas liposomal amphotericin B is moderately supported. Combinations of antifungals as primary treatment options are not recommended. Therapeutic drug monitoring is strongly recommended for patients receiving posaconazole suspension or any form of voriconazole for IA treatment, and in refractory disease, where a personalized approach considering reversal of predisposing factors, switching drug class and surgical intervention is also strongly recommended. Primary prophylaxis with posaconazole is strongly recommended in patients with acute myelogenous leukaemia or myelodysplastic syndrome receiving induction chemotherapy. Secondary prophylaxis is strongly recommended in high-risk patients. We strongly recommend treatment duration based on clinical improvement, degree of immunosuppression and response on imaging.

Usefulness of Aspergillus Galactomannan Antigen Testing and the Prediction of an Outbreak during Hospital Reconstruction.

Objective This study retrospectively evaluated fungal dissemination due to hospital reconstruction and explored effective methods of predicting an outbreak. Methods Patients suspected of having invasive aspergillosis were tested for Aspergillus galactomannan antigen before and after reconstruction, and the mean values of three months of testing for positive patients were determined. The characteristics of patients with aspergillosis during this period were also assessed. Results Forty-five patients were positive for Aspergillus antigen (>0.5 cut-off index) from January 2013 to December 2014. Mean Aspergillus antigen values significantly increased following reconstruction (p<0.05). Three patients developed pneumonia due to Aspergillus and were diagnosed with “probable” invasive aspergillosis according to the European Organization for Research and Treatment of Cancer and the National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG) criteria. We also discovered that the anteroom to contain dust was not prefabricated and a negative pressure system to remove dust was not used. After construction of the unit, no new cases of aspergillosis were diagnosed. Conclusion Many Aspergillus spores may be transiently floating during hospital reconstruction. Therefore, monthly surveillance with frequent serum galactomannan antigen testing to predict outbreaks is necessary. Surveillance of all patients in the hematology ward is especially important. Reconsideration of prophylactic antifungals may also be necessary during hospital reconstruction.

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.

Outbreak of invasive aspergillosis in heart transplant recipients: The role of screening computed tomography scans in asymptomatic patients and universal antifungal prophylaxis.

BackgroundDelays in diagnosing pulmonary invasive aspergillosis (IA), a significant cause of morbidity and mortality among heart transplant recipients (HTRs), may impact on successful treatment. The appropriate screening strategy for IA in these patients remains undefined, particularly in the setting of nosocomial outbreaks. We describe our experience employing chest computed tomography (CT) scans as a screening method for IA. In addition, we comment on antimicrobial prophylaxis in HTRs in the setting of an outbreak.MethodsScreening CT scans of the chest and serum galactomannan (GM) were performed in HTRs during an outbreak that followed the index case of IA. Abnormal CT findings prompted a diagnostic workup. Antimicrobial prophylaxis for new transplants recipients included intravenous micafungin while hospitalized, followed by outpatient inhaled amphotericin B for up to 3 months.ResultsDuring a 10‐month period, five cases of IA were identified among HTRs. Two additional asymptomatic patients were diagnosed with IA among 15 asymptomatic HTRs who underwent screening chest CT scans. Among the five cases of IA in HTRs, two of five (40%) had a partial response and the other three failed voriconazole therapy. Complete response to voriconazole therapy assessed at 12 weeks was achieved in these two asymptomatic HTRs diagnosed via screening CTs. Serum GM was positive only in one of the symptomatic cases. The negative predictive value of CT scans was 100% (95% confidence interval, 71.5%‐100%).ConclusionsIn an outbreak setting, screening CT scans of the chest may aid in early detection of asymptomatic HTRs with IA and improve outcome.

Galactomannan use in clinical practice: providing free testing is not the full answer

IntroductionInvasive aspergillosis is a condition associated with a high mortality rate mostly due to difficulties in performing an early diagnosis. In recent years, galactomannan detection has markedly improved the diagnosis of invasive aspergillosis, but very little is known on how physicians deal with this test in clinical practice. MethodsThis cross-sectional study aimed to analyze the indications for the use of serum galactomannan in a large Brazilian hospital, between 2015 and 2016. No specific protocol was in place for GM request. We reviewed the medical records of adult (>18 years-old) patients who were tested for galactomannan due to one the following indications: screening, diagnosis, or treatment follow-up. Additional variables included demographic data, underlying diseases, presence of neutropenia, and use of previous antifungal (anti-Aspergillus) drugs. ResultsThe mean age of the patients was 51 years-old (sd±15.8), and 63.3% of patients were male. Patients with hematological malignancies accounted for 60.1% of the cases, mostly acute myeloid leukemia (19.6%). Galactomannan testing was positive in 12.2% of patients, including 1.6% of occasions in which the test was used for screening purposes, 13.2% for diagnosis, and 32.4% during follow-up. Median time for chest imaging request was two days before GM testing. Previous antifungal therapy was reported for 35.1% of patients, mostly amphotericin B (57.1%). ConclusionThe correct use of galactomannan testing is essential for an early diagnosis of invasive aspergillosis, which may improve the prognosis of the disease. We demonstrated that clinicians usually ask for galactomannan tests to confirm imaging findings in patients who frequently were on antifungal drugs, something that could be improved by medical education. We observed a low frequency of galactomannan use for preemptive antifungal therapy (25.7%), which is worrying considering the well-known beneficial use of GM testing in this scenario.

Circulating Aspergillus fumigatus DNA Is Quantitatively Correlated to Galactomannan in Serum.

The performance of antigen galactomannan (GM) for diagnosing invasive aspergillosis (IA) is hampered by the occurrence of false-positive results. Quantitative PCR has been proposed to improve the diagnosis of IA. Therefore, we analyzed the value of performing a PCR test to the GM-positive serum sample. Using a quantitative PCR assay specific for Aspergillus fumigatus 28S ribosomal DNA, we retrospectively tested 422 GM-positive (Platelia Bio-Rad kit) serum samples collected over 1 year from 147 patients. The cases were classified based on EORTC criteria as “proven,” “probable,” and “no–IA” before availability of the PCR results. After exclusion of 65 samples for non-reproducibility of GM positivity (n = 62) or PCR inhibition (n = 3), 75 (21.0%) of the remaining 357 samples were PCR-positive. GM and fungal DNA showed a significantly positive correlation (p < 0.0001, R2 = 0.27, slope = 0.98 ± 0.19). At least one PCR-positive result was observed in 63.3% (31/49) of IA patients and in 13.2% (13/98) of non-IA patients (p < 0.0001). The PCR positivity was also associated with the presence of other microbiological criteria among the 44 patients with IA and complete mycological workup (p = 0.014), as well as a higher mortality rate at six months among the 135 patients with hematological conditions (p = 0.0198). Overall, we found a quantitative correlation between serum GM and circulating DNA with an increased likelihood of IA when both were positive. A PCR-positive result also supported a higher fungal load when GM was already positive. We advocate adding a PCR test for every confirmed GM-positive serum sample.

Utility of a serum Aspergillusgalactomannan assay in diagnosis of invasive pulmonary Aspergillosis in HIV/AIDS patients: a prospective analysis

Background: Invasive pulmonary aspergillosis (IPA) is a life threatening infection among immunocompromised patients. A timely and precise diagnosis of this condition is often precluded by lack of sensitive and specific noninvasive diagnostic tools. Detection of galactomannan has emerged as a promising tool in this regard. While the analytical performance of serum galactomannan assay has been extensively evaluated in various high risk groups, its possible utility in HIV/AIDS patients is yet to be explored. The present study was undertaken to evaluate the yield of a serum galactomannan assay for diagnosis of IPA in a cohort of HIV/AIDS patients.Methods: 49 febrile HIV reactive patients with co-existent symptomatic AIDS were prospectively enrolled for the evaluation. Blood samples were drawn from each patient and serum galactomannan screening was performed employing the commercially available serum galactomannan assay, Platelia™ Aspergillus EIA. An optical density index >0.5 for at least two serum samples was considered the defining criteria for a positive result. Furthermore, sputum samples were collected and direct microscopic examination (10% potassium hydroxide wet mount) and fungal cultures were performed.Result: In accordance with the definitions laid down under EORTC/MSG (European Organization for Research and Treatment of Cancer / Mycoses Study Group) criteria, ten cases of probable and 23 cases of possible IPA were diagnosed. The sensitivity, specificity, and positive and negative predictive values of Platelia™ Aspergillus EIA for patients with probable IPA were 90%, 100%, 100% and 94.12 % respectively.Conclusion: Serum galactomannan assay has a high sensitivity and specificity and when complemented with relevant lower respiratory tract symptomatology and imaging findings, can serve as a useful adjunct to conventional modalities for the diagnosis of IPA in HIV/AIDS patients. DOI: 10.21276/APALM.1439