Diagnostic performance of serum galactomannan and β-D-glucan for invasive aspergillosis in suspected patients: A meta-analysis

BACKGROUND

Serum galactomannan (GM) and β-D-glucan (BG) are known markers of invasive aspergillosis (IA). The aim of this meta-analysis was to evaluate the efficiency of serum GM and BG as diagnostic markers of symptomatic IA infection and compare the performance of the combined tests with that of either test individually.

METHODS

A literature search was carried out using PubMed, Web of Science, and EMBASE databases to include relevant studies published in English up to May 2023. The quality assessment was performed using Review Manager 5.3 software. A bivariate model was applied to pool diagnostic parameters using Stata 14.0 software. We used Cochrane I2 index to assess heterogeneity and identify the potential source of heterogeneity by meta-regression. Paired t tests were used to compare the value of GM and BG for IA diagnosis when used in combination or alone.

RESULTS

Sixteen studies were eligible for inclusion in the meta-analysis. For proven or probable IA, serum GM and BG yielded a pooled sensitivity of 0.53 (95% CI 0.40-0.66) vs 0.72 (95% CI 0.61-0.81) and a pooled specificity of 0.94 (95% CI 0.91-0.97) vs 0.82 (95% CI 0.73-0.88). The area under the curve (AUC) of ROC was 0.90 (95% CI 0.87-0.92) vs 0.83 (95% CI 0.80-0.86) for all studies. The pooled sensitivity and specificity for IA diagnosis by combined GM and BG assays (GM/BG) were 0.84 (95% CI 0.69-0.86) and 0.76 (95% CI 0.69-0.81), respectively. The sensitivity of the combined GM/BG test to diagnose IA was higher than of the GM or BG test alone.

CONCLUSION

Serum GM and BG tests had a relatively high accuracy for IA diagnosis in suspected patients. The diagnostic accuracy of both assays is comparable, and the diagnostic sensitivity is further improved by the combined detection of the 2 markers.

Recent Advances in the Preparation, Structure, and Biological Activities of β-Glucan from Ganoderma Species: A Review

Ganoderma has served as a valuable food supplement and medicinal ingredient with outstanding active compounds that are essential for human protection against chronic diseases. Modern pharmacology studies have proven that Ganoderma β-d-glucan exhibits versatile biological activities, such as immunomodulatory, antitumor, antioxidant, and antiviral properties, as well as gut microbiota regulation. As a promising polysaccharide, β-d-glucan is widely used in the prevention and treatment of various diseases. In recent years, the extraction, purification, structural characterization, and pharmacological activities of polysaccharides from the fruiting bodies, mycelia, spores, and fermentation broth of Ganoderma species have received wide attention from scholars globally. Unfortunately, comprehensive studies on the preparation, structure and bioactivity, toxicology, and utilization of β-d-glucans from Ganoderma species still need to be further explored, which may result in limitations in future sustainable industrial applications of β-d-glucans. Thus, this review summarizes the research progress in recent years on the physicochemical properties, structural characteristics, and bioactivity mechanisms of Ganoderma β-d-glucan, as well as its toxicological assessment and applications. This review is intended to provide a theoretical basis and reference for the development and application of β-d-glucan in the fields of pharmaceuticals, functional foods, and cosmetics.

Current and Future Pathways in Aspergillus Diagnosis

Aspergillus fumigatus has been designated by the World Health Organization as a critical priority fungal pathogen. Some commercially available diagnostics for many forms of aspergillosis rely on fungal metabolites. These encompass intracellular molecules, cell wall components, and extracellular secretomes. This review summarizes the shortcomings of antibody tests compared to tests of fungal products in body fluids and highlights the application of β-d-glucan, galactomannan, and pentraxin 3 in bronchoalveolar lavage fluids. We also discuss the detection of nucleic acids and next-generation sequencing, along with newer studies on Aspergillus metallophores.

Serology anno 2021-fungal infections: from invasive to chronic

BACKGROUND

Diagnosing invasive or chronic fungal infections is a challenge, particularly in the immunocompromised host. Microscopy and culture remain the reference standard, but are insensitive. The use of non-culture-based techniques is recommended in conjunction with conventional methods to improve the diagnostic yield.

OBJECTIVES

The aim was to provide an updated 2021 inventory of fungal antigen and serology tests for diagnosing invasive and chronic fungal infections, the key focus was set on Aspergillus, Candida and Cryptococcus species.

SOURCES

Pubmed search for publications with the key words fungal antigen tests, laboratory-based diagnosis of invasive pulmonary aspergillosis, chronic pulmonary aspergillosis, invasive candidiasis, invasive fungal infections and cryptococcal infections published from 2017 to 2020.

CONTENT

Antigen assays such as the galactomannan (GM) and β-d-glucan detection systems are frequently used, but these tests vary in sensitivity and specificity, depending on the patient population involved, specimens inspected, cut-offs defined, test strategy applied and inclusion or exclusion of possible fungal case definitions. Multiple different detection systems are available, with recently introduced new point-of-care tests such as the lateral flow device and the lateral flow assay. Despite a wide heterogeneity in populations evaluated, studies indicate a better diagnostic performance of bronchoalveolar lavage GM in comparison with serum GM, and a suboptimal specificity of GM bronchoalveolar lavages (cut-off ≥1) and serum β-d-glucan in non-neutropenic individuals. Point-of-care cryptococcal antigen tests show excellent performance.

IMPLICATIONS

There are fungal antigen detection tests available with excellent to reasonable clinical performance to diagnose invasive fungal infections. Only a few assays are useful to monitor therapeutic response. There are multiple marketed IgG antibody tests to detect Aspergillus fumigatus antibodies, the titres vary widely and the performance differs significantly. In general, diagnostic tests are vulnerable to being affected by the host, the microbe and laboratory setting.

Clinical Outcomes of Radical Surgery and Antimicrobial Agents in Vascular Pythiosis: A Multicenter Prospective Study

Vascular pythiosis is a rare, neglected, life-threatening disease with mortality of 100% in patients with incomplete surgical resection or patients with persistently elevated serum β-d-glucan (BDG). The study was conducted to understand the clinical outcomes of new treatment protocols and potential use of erythrocyte sedimentation rate (ESR) and c-reactive protein (CRP) as alternative monitoring tools, given recent favorable minimum inhibitory concentrations (MICs) of antibacterial agents and prohibitive cost of serum BDG in Thailand. A prospective cohort study of patients with vascular pythiosis was conducted between February 2019 and August 2020. After diagnosis, patients were followed at 0.5, 1, 1.5, 3, and 6 months. Descriptive statistics, Spearman's correlation coefficient, and general linear model for longitudinal data were used. Amongst the cohort of ten vascular pythiosis patients, four had residual disease after surgery. Among four with residual disease, one developed disseminated disease and died, one developed relapse disease requiring surgery, and two were successfully managed with antimicrobial agents. The spearman's correlation coefficients between BDG and ESR, and between BDG and CRP in patients without relapse or disseminated disease were 0.65 and 0.60, respectively. Tetracyclines and macrolides had most favorable minimum inhibitory concentrations and synergistic effects were observed in combinations of these two antibiotic classes. Adjunctive use of azithromycin and doxycycline preliminarily improved survival in vascular pythiosis patients with residual disease. Further studies are needed to understand the trends of ESR and CRP in this population.

Diagnostic Performance of Bronchoalveolar Lavage (1,3)-β-d-Glucan Assay for Pneumocystis jirovecii Pneumonia

We evaluated the performance of the (1,3)-β-d-glucan (BDG) assay on bronchoalveolar lavage fluid (BALF) as a possible aid to the diagnosis of Pneumocystis jirovecii pneumonia. BALF samples from 18 patients with well-characterized proven, probable, and possible Pneumocystis pneumonia and 18 well-matched controls were tested. We found that the best test performance was observed with a cut-off value of 128 pg/mL; receiver operating characteristic/area under the curve (ROC/AUC) was 0.70 (95% CI 0.52–0.87). Sensitivity and specificity were 78% and 56%, respectively; positive predictive value was 64%, and negative predictive value was 71%. The low specificity that we noted limits the utility of BALF BDG as a diagnostic tool for Pneumocystis pneumonia.

pH-sensitive PEG-coated hyper-branched β-d-glucan derivative as carrier for CpG oligodeoxynucleotide delivery

β-d-glucan is a natural non-digestible polysaccharide that can be selectively recognized by recognition receptors such as Dectin-1 receptors, resulting in an emerging interest on exploring its capacity for carrying biological information to desired organs or cells. CpG oligodeoxynucleotide (ODN) has the potentiality to initiate an immune-stimulatory cascade via activating B cells inducing proinflammatory cytokines, which is conducive to immunotherapy and nucleic acid vaccine. Herein, we developed a pH-sensitive delivery system loading with CpG ODN by introducing poly-ethylenimine (PEI) to a hyperbranched β-d-glucan (HBB) and coating with poly-ethylene glycol (PEG) shell via acidic liable Schiff bond. This delivery system exhibited a favorable biocompatibility and facilitated the cellular uptake of CpG ODN at pH 6.8 with the possibility of having higher accumulation in acidic cancer microenvironment. Furthermore, this carrier together with class B CpG ODN could enhance the secretion of cytokines including interleukin-6 and interferon-α as well as capable of interferon-α induction.

Limited Positive Predictive Value of β-d-Glucan in Hematologic Patients Receiving Antimold Prophylaxis

Background

Diagnostic value of β-d-glucan (BDG) in populations with low prevalence of invasive fungal infection (IFI), such as hematologic patients receiving antimold prophylaxis, should be re-evaluated.

Methods

We retrospectively reviewed episodes with BDG results in hematologic patients receiving antimold prophylaxis from January 2017 to August 2019 in a tertiary hospital. The episodes were classified as true positive ([TP] positive BDG with IFI), true negative ([TN] negative BDG without IFI), false positive ([FP] positive BDG without IFI), false negative ([FN] negative BDG with IFI), and nonevaluable.

Results

A total of 203 episodes were analyzed: 101 episodes (49.8%) were from stem cell transplants, 89 (43.8%) were from induction chemotherapy, and 13 (6.4%) were from graft-versus-host disease treatment. There were 62 nonevaluable episodes. Among 141 evaluable ones, there were 8 (5.7%) episodes of probable/proven IFI. True positive, TN, FP, and FN cases were 4 (2.8%), 112 (79.4%), 21 (14.9%), and 4 (2.8%) episodes, respectively. Sensitivity, specificity, positive predictive value, and negative predictive value were 50.0%, 84.2%, 16.1%, and 96.5%, respectively. Positive predictive value was 26.7% and 0.0% in diagnostic and surveillance episodes, respectively.

Conclusions

β-d-glucan test should be used to exclude IFI rather than for diagnosis in these patients.

Point-Counterpoint: Should Serum β-d-Glucan Testing Be Used for the Diagnosis of Pneumocystis jirovecii Pneumonia?

INTRODUCTIONDespite the widespread use of prophylactic antibiotics in high-risk individuals, Pneumocystis jirovecii remains an important cause of pneumonia in immunocompromised patients. During the peak of the AIDS epidemic, many hospitals and outpatient clinics were very proficient at collecting induced sputum specimens for the diagnosis of Pneumocystis jirovecii pneumonia (PJP). With the dramatic reduction in the occurrence PJP in the current era of highly effective antiretroviral therapy, many centers no longer collect induced sputum samples. Thus, the diagnosis of PJP requires bronchoalveolar lavage (BAL) specimens or a decision to treat the patient empirically without a definitive diagnosis. Sputum or BAL specimens are tested for P. jirovecii using special stains or molecular assays, which require highly trained staff that may not be available with a rapid turnaround time. Given the invasive nature of collecting BAL specimens and the expertise needed for interpreting PJP test results, there is interest in using serum 1,3-β-d-glucan (BDG) testing for the diagnosis of PJP. In this point-counterpoint, Luis Ostrosky-Zeichner and Gabriela Corsi-Vasquez discuss the pro view of using BDG testing for the diagnosis of PJP, while Paul E. Sax and Edward F. Pilkington III present the con view of using BDG testing for the diagnosis of PJP.

Structural Characterization and Chain Conformation of Water-Soluble β-Glucan from Wild Cordyceps sinensis

Water-soluble β-d-glucan was obtained from wild Cordyceps sinensis by alkali solution and ethanol precipitation. The structure characteristics were determined using high-performance anion-exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD), methylation combined with gas chromatography-mass spectrometry, and one-/two-dimensional nuclear magnetic resonance spectroscopy. Results showed that β-d-glucan had a structure of every seven (1→3)-β-d-Glcp backbone residues with two (1→6)-β-d-Glcp branches. Additionally, conformation properties in different solvents were investigated by static light scattering, dynamic light scattering, and HPSEC with multiple detectors. It was found that β-d-glucan in 0.5 M NaOH had a narrow unimodal distribution of hydrodynamic radius displaying a spherical coil conformation, whereas it formed severe aggregation in dimethyl sulfoxide. In 0.1 M NaNO₃, β-d-glucan mainly existed as a rod-like conformation corresponding to a helical structure together with small aggregates (10%). This work added more information to the understanding of C. sinensis polysaccharides.

Purification, structural characterization, and immunomodulatory activity of the polysaccharides from Ganoderma lucidum

A preliminary relationship was illustrated between the structural characteristics and corresponding immunomodulatory activities of G. lucidum polysaccharides. Two polysaccharides (GLP-1 and GLP-2) were purified from Ganoderma lucidum extracts by gradient ethanol precipitation and a Q-Sepharose Fast Flow (QFF) strong anion-exchange column. The monosaccharide composition, high-performance gel permeation chromatography-multi-angle laser light scattering-refractive index (HPGPC-MALLS-RI), Fourier-transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), methylation analysis, and nuclear magnetic resonance (NMR) were used to characterize these polysaccharides. The GLP-1 polysaccharide was elucidated as d-galactoglucan with a flexible random linear conformation that mainly composed of →6)-β-d-Glcp-(1→, →6)-α-d-Galp-(1→, and →3)-β-d-Glcp-(1→ residues. GLP-2 was found to be a relatively homogeneous β-d-glucan that possessing →6)-β-d-Glcp-(1→ and →3)-β-d-Glcp-(1→ residues packaged into a spherical conformation. Immunomodulatory activities in vivo demonstrated that GLP-1 produced better protection of the spleen and thymus and was more effective for promoting hematopoiesis and improving IgA levels in serum. Our results suggest that the immunomodulatory activities of G. lucidum polysaccharides are highly corresponded to their structural characteristics such as carbohydrate composition, molecular weight and advanced conformation. This study provides a preliminary basis for studying the relationship between polysaccharide structure characterization and pharmacological activities.

N-Terminal (1→3)-β-d-Glucan Recognition Proteins from Insects Recognize the Difference in Ultra-Structures of (1→3)-β-d-Glucan

Recognition of (1→3)-β-d-glucans (BGs) by invertebrate β-1,3-d-glucan recognition protein (BGRP) plays a significant role in the activation of Toll pathway and prophenoloxidase systems in insect host defense against fungal invasion. To examine the structure diversity of BGRPs for the recognition of physiochemically different BGs, the binding specificity of BGRPs cloned from four different insects to structure different BGs was characterized using ELISA. Recombinant BGRPs expressed as Fc-fusion proteins of human IgG1 bound to the solid phase of BGs. Based on the binding specificities, the BGRPs were categorized into two groups with different ultrastructures and binding characters; one group specifically binds BGs with triple-helical conformation, while the other group recognizes BGs with disordered conformations like single-helical or partially opened triple helix. The BGRPs from the silkworm and the Indian meal moth bound to the BGs with a triple-helical structure, whereas BGRPs from the red flour beetle and yellow mealworm beetle showed no binding to triple-helical BGs, but bound to alkaline-treated BGs that have a partially opened triple-helical conformation. This evidence suggests that the insect BGRPs can distinguish between different conformations of BGs and are equipped for determining the diversity of BG structures.

Evaluation of Aspergillus-Specific Lateral-Flow Device Test Using Serum and Bronchoalveolar Lavage Fluid for Diagnosis of Chronic Pulmonary Aspergillosis

The Aspergillus-specific lateral-flow device (AspLFD) test is a newly developed point-of-care diagnostic method for invasive pulmonary aspergillosis. However, evidence of the diagnostic performance of the AspLFD for chronic pulmonary aspergillosis (CPA) is limited. Therefore, we conducted a retrospective study to investigate this in comparison with the galactomannan (GM) β-d-glucan (BDG) test. Fifty patients with chronic pulmonary aspergillosis and 65 patients with respiratory disease, as a control, were enrolled in this study. The majority of the CPA disease entities were chronic pulmonary aspergillosis (64.0%, n = 32), followed by subacute invasive pulmonary aspergillosis (IPA) (20.0%, n = 10) and simple pulmonary aspergilloma (SPA) (16.0%, n = 8). The sensitivity and specificity of the AspLFD test in serum samples were 62.0% and 67.7%, respectively. The GM test (cutoff index, 1.54) showed a sensitivity of 22% and a specificity of 92.3%, while the sensitivity and specificity of the BDG test (cutoff, 19.3 pg/ml) were 48% and 90.8%, respectively. In bronchoalveolar lavage fluid samples, the AspLFD test showed a sensitivity of 66.7% and a specificity of 69.2%, while those of the GM test (cutoff index, 0.6) were 72.7% and 83.1%, respectively. The Aspergillus precipitating antibody test had 70% sensitivity. Unlike the Aspergillus precipitating antibody test, the AspLFD on serum samples showed similar sensitivity to non-fumigatus Aspergillus species. Patients with false-positive results for the AspLFD on serum samples were of a significantly higher age and had a higher prevalence of cavitary lesions in chest computed tomography than patients with negative results in the control group. Given the results in this study, the performance of the AspLFD using serum was acceptable as a point-of-care test for the diagnosis of CPA.

Evaluation of a Turbidimetric β-d-Glucan Test for Detection of Pneumocystis jirovecii Pneumonia

Currently, diagnosis of Pneumocystis jirovecii pneumonia (PJP) relies on analysis of lower respiratory specimens, either by microscopy or quantitative real-time PCR (qPCR). Thus, bronchoscopy is required, which is associated with increased risk of respiratory failure. We assessed the value of noninvasive serologic β-d-glucan (BDG) testing for laboratory diagnosis of PJP using a newly available turbidimetric assay. We identified 73 cases of PJP with positive qPCR results from lower respiratory specimens for Pneumocystis and serology samples dating from 1 week before to 4 weeks after qPCR. In addition, 25 sera from controls with suspected PJP but specimens negative for Pneumocystis by qPCR were identified. Sera were tested with a turbidimetric BDG assay (Fujifilm Wako Chemicals Europe GmbH, Neuss, Germany), using an 11-pg/ml cutoff. Sensitivity and specificity were calculated based on qPCR test results as a reference. The turbidimetric BDG assay identified 63/73 patients with positive or slightly positive qPCR tests for an overall sensitivity of 86%; after exclusion of cases with only slightly positive qPCR results, sensitivity was 91%. No correlation between serum BDG levels and respiratory specimen DNA levels was found. Serologic BDG testing was negative in 25/25 controls with negative qPCR for a specificity of 100% using the predefined cutoff. In 22/25 samples (88%), no BDG was detected. Serologic BDG testing using the turbidimetric assay showed high sensitivity and specificity compared to qPCR of lower respiratory specimens for the diagnosis of PJP. Both turnover time and test performance will allow clinicians to delay or in some cases forego bronchoscopy.

Modulation of vascular function and anti-aggregation effect induced by (1→3) (1→6)-β-d-glucan of Saccharomyces cerevisiae and its carboxymethylated derivative in rats

BACKGROUND

β-d-Glucans are polysaccharides found in the cell walls of yeasts, such as Saccharomyces cerevisiae, and they have been studied because of their beneficial effects on health, mainly in terms of immunomodulation. However, information on the action of these polymers on vascular and platelet function is still scarce. This study evaluate the effect of (1→3) (1→6) β-d-glucan (βG-Sc) and its carboxymethylated derivative (CM-G) on vascular and platelet function in rats.

METHODS

The animals received daily oral treatments with βG-Sc (20mg/kg) and CM-G (20mg/kg) for eight days. Next, cytokine quantification, vascular reactivity and adenosine diphosphate (ADP)- and collagen-induced platelet aggregation studies were performed. In vitro platelet aggregation and P-selectin exposition assays were conducted using 100 and 300μg/mL CM-G.

RESULTS

The CM-G-treated group had less IL-8 than did the control. In reactivity experiments, CM-G and βG-Sc treatments did not change the contractile response of the vessel induced by PHE. Moreover, only CM-G improved the vasorelaxation response to Nitroprusside (SPN, a nitric oxide donor). The in vitro aggregation studies showed that at the highest concentration (300μg/mL), CM-G inhibited the agonist-induced platelet aggregation with an effect similar to that of acetylsalicylic acid and without affecting P-selectin exposition. The treatments with βG-Sc or CM-G inhibited the platelet aggregation stimulated by ADP, but only βG-Sc treatment was effective in affect the collagen-stimulated aggregation.

CONCLUSIONS

These findings suggest that CM-G modulate positively the vascular function, mainly in responses NO-dependent. CM-G and βG-Sc have an anti-aggregation effect, being CM-G more selective to ADP-induced platelet aggregation.

Invasive Candidiasis in Various Patient Populations: Incorporating Non-Culture Diagnostic Tests into Rational Management Strategies

Mortality rates due to invasive candidiasis remain unacceptably high, in part because the poor sensitivity and slow turn-around time of cultures delay the initiation of antifungal treatment. β-d-glucan (Fungitell) and polymerase chain reaction (PCR)-based (T2Candida) assays are FDA-approved adjuncts to cultures for diagnosing invasive candidiasis, but their clinical roles are unclear. We propose a Bayesian framework for interpreting non-culture test results and developing rational patient management strategies, which considers test performance and types of invasive candidiasis that are most common in various patient populations. β-d-glucan sensitivity/specificity for candidemia and intra-abdominal candidiasis is ~80%/80% and ~60%/75%, respectively. In settings with 1%–10% likelihood of candidemia, anticipated β-d-glucan positive and negative predictive values are ~4%–31% and ≥97%, respectively. Corresponding values in settings with 3%–30% likelihood of intra-abdominal candidiasis are ~7%–51% and ~78%–98%. β-d-glucan is predicted to be useful in guiding antifungal treatment for wide ranges of populations at-risk for candidemia (incidence ~5%–40%) or intra-abdominal candidiasis (~7%–20%). Validated PCR-based assays should broaden windows to include populations at lower-risk for candidemia (incidence ≥~2%) and higher-risk for intra-abdominal candidiasis (up to ~40%). In the management of individual patients, non-culture tests may also have value outside of these windows. The proposals we put forth are not definitive treatment guidelines, but rather represent starting points for clinical trial design and debate by the infectious diseases community. The principles presented here will be applicable to other assays as they enter the clinic, and to existing assays as more data become available from different populations.

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.

Diagnostic Modalities for Invasive Mould Infections among Hematopoietic Stem Cell Transplant and Solid Organ Recipients: Performance Characteristics and Practical Roles in the Clinic

The morbidity and mortality of hematopoietic stem cell and solid organ transplant patients with invasive fungal infections (IFIs) remain high despite an increase in the number of effective antifungal agents. Early diagnosis leading to timely administration of antifungal therapy has been linked to better outcomes. Unfortunately, the diagnosis of IFIs remains challenging. The current gold standard for diagnosis is a combination of histopathology and culture, for which the sensitivity is <50%. Over the past two decades, a plethora of non-culture-based antigen and molecular assays have been developed and clinically validated. In this article, we will review the performance of the current commercially available non-cultural diagnostics and discuss their practical roles in the clinic.

A comprehensive diagnostic approach using galactomannan, targeted β-d-glucan, baseline computerized tomography and biopsy yields a significant burden of invasive fungal disease in at risk haematology patients

Invasive fungal disease (IFD) is difficult to diagnose. We investigated the incidence of IFD and risk factors using the revised European Organization for Research and Treatment of Cancer (EORTC) and the Mycoses Study Group (MSG) definitions. Patients (N = 203) undergoing intensive therapy with expected neutropenia ≥10 d were recruited prospectively and followed for a median (range) of 556 (12-730) d. Baseline chest computerized tomography (CT) was performed pre-therapy. Twice-weekly surveillance with galactomannan (GM) was combined with targeted β-d-glucan (BDG) testing on patients with possible IFD or who were GM-positive. Tissue diagnosis was obtained whenever possible. The cumulative incidence of proven/probable IFD among the 202 evaluable cases after 2 years follow-up was 21%, including 14 proven and 30 probable IFDs. Using either GM or BDG as the sole biomarker (plus host and clinical evidence) the apparent overall incidence of proven/probable IFD was 11% and 16%, respectively. Combined GM/BDG detected all biopsy-proven mould IFD. Baseline CT abnormalities were found in 76/202 (38%) patients. Baseline CT abnormalities and Karnofsky score <90, monocytopenia >10 d and bacteraemia were independent risk factors associated with greater than twofold increased IFD risk. This combined diagnostic approach identified a high incidence of IFD and important risk factors in this cohort.

Structural characterization and anti-inflammatory activity of a linear β-D-glucan isolated from Pleurotus sajor-caju

Glucans comprise an important class of polysaccharides present in basidiomycetes with potential biological activities. A (1 → 3)-β-D-glucan was isolated from Pleurotus sajor-caju via extraction with hot water followed by fractionation by freeze-thawing and finally by dimethyl sulfoxide extraction. The purified polysaccharide showed a (13)C-NMR spectrum with six signals consisting of a linear glucan with a β-anomeric signal at 102.8 ppm and a signal at 86.1 ppm relative to O-3 substitution. The other signals at 76.2, 72.9, 68.3, and 60.8 ppm were attributed to C5, C2, C4, and C6, respectively. This structure was confirmed by methylation analysis, and HSQC studies. The β-d-glucan from P. sajor-caju presented an immunomodulatory activity on THP-1 macrophages, inhibited the inflammatory phase of nociception induced by formalin in mice, and reduced the number of total leukocytes and myeloperoxidase levels induced by LPS. Taken together, these results demonstrate that this β-d-glucan exhibits a significant anti-inflammatory activity.

Extraction optimization and antinociceptive activity of (1→3)-β-d-glucan from Rhodotorulamucilaginosa

β-d-glucans are polymers of d-glucose monomers found in the cell walls of many bacteria, plants, fungi and yeasts. A variety of β-d-glucans differing in structures have been isolated from various sources and their biological activity to be regulated by various structural factors, such as the primary structure, molecular weight, solubility, and conformation. This study investigated the effect of extraction time and temperature on the yield of β-d-glucan produced by Rhodotorulamucilaginosa. A statistical Doehlert design was applied to determine the important effects and interactions of these independent variables on the yield of β-d-glucan, the dependent variable. Significant models were obtained. The best yield was of 25% obtained after 128min of extraction in a temperature of 72°C. The polysaccharides were characterized as (1⟶3)-β-d-glucan by methods spectroscopic (FT-IR, (1)HNMR and (13)CNMR). In addition, the antinociceptive effect was evaluated using different experimental tests (acetic acid-induced writhing test, formalin test and tail immersion test). The (1⟶3)-β-d-glucan showed a potent peripheral antinociceptive effect, possibly by the inhibition of inflammatory mediators.