Dextrose-containing fluids causing false-positive serum galactomannan: a case-control study and interrupted time series analysis

OBJECTIVES

This study aimed to identify the cause of false-positive serum Aspergillus antigen galactomannan (GM) results in our centre.

METHODS

We performed a case-control study aiming to elucidate the factors associated with false-positive GM results. Independent risk factors for false-positive GM were evaluated through a multivariable regression analysis. An interrupted time series analysis was used to evaluate the effectiveness of an intervention removing the identified factors.

RESULTS

Among 568 patients tested, GM was positive in 130 patients of whom 97 had false-positive GM (cases). These were compared with 427 patients with true-negative GM (controls). Administration of dextrose-containing fluids within 6 days before GM testing was an independent predictor for false-positive GM results (adjusted odds ratio [aOR], 18.60; 95% CI, 8.95-38.66. An analysis of GM presence in different dextrose-containing fluids revealed positivity in 34.8% (8 of 23) (manufacturer A) and 33.3% (5 of 15) (manufacturer B) of the samples. Investigation of the manufacturing process revealed that the saccharification process employed enzymes derived from Aspergillus niger. After identifying the root cause of false positivity, GM-containing dextrose fluid use was restricted. Interrupted time series analysis showed an immediate reduction of GM false-positivity (-6.5% per week, p = 0.045) and a declining trend (-0.33% per week, p = 0.005) postintervention.

CONCLUSIONS

Administering dextrose-containing fluids was the primary factor causing false-positive serum Aspergillus antigen GM assay results. Our investigation led to a modification of the manufacturing process of the dextrose-containing fluids.

Performance of the galactomannan test for the diagnosis of invasive pulmonary aspergillosis using non-invasive proximal airway samples

OBJECTIVE

To diagnose invasive pulmonary aspergillosis (IPA), galactomannan (GM) detection in serum or bronchoalveolar lavage fluid (BALF) is widely used. However, the utility of proximal airway GM test (from induced sputum or tracheal aspirate) has not been well elucidated.

METHODS

In this retrospective cohort study, we evaluated the diagnostic performance of proximal airway GM in diagnosis of IPA including COVID-19 associated pulmonary aspergillosis (CAPA). Between January 2022 and January 2023, patients who had been tested for GM with clinical suspicion or for surveillance from any specimen (serum, induced sputum, tracheal aspirate, and BALF) were screened. IPA was diagnosed using EORTC/MSGERC criteria, and CAPA was diagnosed following the 2020 ECMM/ISHAM consensus criteria.

RESULTS

Of 624 patients with GM results, 70 met the criteria for proven/probable IPA and 427 had no IPA. The others included possible IPA and chronic form of aspergillosis. The sensitivities and specificities of serum, proximal airway, and BALF GM for proven/probable IPA versus no IPA were 78.9% and 70.6%, 93.1% and 78.7%, and 78.6% and 91.0%, respectively. Areas under the receiver operating characteristic curve (AUCs) were 0.742 for serum GM, 0.935 for proximal airway GM, and 0.849 for BALF GM (serum GM vs proximal airway GM, p = 0.014; proximal airway GM vs BALF GM, p = 0.334; serum GM vs BALF GM, p = 0.286).

CONCLUSION

This study demonstrates that the performance of GM test from non-invasive proximal airway samples is comparable or even better than those from serum and distal airway sample (BALF).

Galactomannan inhibits Trichinella spiralis invasion of intestinal epithelium cells and enhances antibody-dependent cellular cytotoxicity related killing of larvae by driving macrophage polarization

Previous studies have shown that recombinant Trichinella spiralis galectin (rTsgal) is characterized by a carbohydrate recognition domain sequence motif binding to beta-galactoside, and that rTsgal promotes larval invasion of intestinal epithelial cells. Galactomannan is an immunostimulatory polysaccharide composed of a mannan backbone with galactose residues. The aim of this study was to investigate whether galactomannan inhibits larval intrusion of intestinal epithelial cells and enhances antibody-dependent cellular cytotoxicity (ADCC), killing newborn larvae by polarizing macrophages to the M1 phenotype. The results showed that galactomannan specially binds to rTsgal, and abrogated rTsgal facilitation of larval invasion of intestinal epithelial cells. The results of qPCR, Western blotting, and flow cytometry showed that galactomannan and rTsgal activated macrophage M1 polarization, as demonstrated by high expression of iNOS (M1 marker) and M1 related genes (IL-1β, IL-6, and TNF-α), and increased CD86+ macrophages. Galactomannan and rTsgal also increased NO production. The killing ability of macrophage-mediated ADCC on larvae was also significantly enhanced in galactomannan- and rTsgal-treated macrophages. The results demonstrated that Tsgal may be considered a potential vaccine target molecule against T. spiralis invasion, and galactomannan may be a novel adjuvant therapeutic agent and potential vaccine adjuvant against T. spiralis infection.

Evernia prunastri lichen as a source of bioactive glucans with potential for topical applications

Microwave hydrothermal treatment was selected to extract valuable fractions with bioactive and gelling properties from Evernia prunastri lichen with potential for topical applications. The impact of the extraction processing conditions on the soluble extracts, mucilage fraction and residual solid phase was analyzed within a lichen global valorization approach. A particular stress was made on the thermo-rheological and structural characteristics of the extracted glucan and galactomannan polymers, the corresponding gelled matrices, and their cosmetic feasibility. Results revealed that the proposed microwave-assisted treatment showed a relevant influence on the phytochemical features of the aqueous soluble extracts, accounting the major protein content at 120 °C and the enhanced antioxidant and anti-tyrosinase properties at 140 °C. Extracts at 200 °C showed the highest anti-inflammatory (COX-1 and COX-2 inhibition) efficacies. The biopolymer analyses indicated that those recovered after lichen hydrothermal treatment at 160 °C featured a good extraction performance, the highest molecular weight, apparent viscosity, and antiproliferative potential. The thermo-rheological properties of the corresponding matrices formulated at 10 % and 60 or 80 °C exhibited the strongest and most thermo-reversible characteristics, as well as antifreezing feasibility. Another advantage of the selected fractions was the absence of skin irritation according to the in vitro skin irritation assay.

COVID-19-associated pulmonary aspergillosis in intensive care unit: A real-life experience

Since 2020, cases of COVID-19-associated pulmonary aspergillosis (CAPA) have been frequently described, representing an important cause of mortality, especially among patients admitted to intensive care unit (ICU). A predisposition to invasive infection caused by Aspergillus spp. in SARS-CoV-2 infected patients can be ascribed either to the direct viral-mediated damage of the respiratory epithelium or to the dysregulated immunity associated with COVID-19. In this case series we have collected the clinical, laboratory and radiological data of 10 patients admitted to the ICU with diagnosis of probable CAPA, according to the recent expert consensus statement, from March 2020 to December 2022 in the Teaching Hospital of Catanzaro in Italy. Overall, 249 patients were admitted to the COVID-19-ICU from March 2020 to December 2022; out of these, 4% developed a probable CAPA. Most of patients were male with a mean age of 62 years. Only two patients had an underlying immunocompromising condition. The observed mortality was 70%. In our institution, all COVID-19 patients requiring invasive mechanical ventilation systematically underwent bronchoscopy with bronchoalveolar lavage for an early evaluation of bacterial and/or fungal co- or super-infections, including galactomannan test. Patients were re-evaluated by an infectious diseases consultant team every 24-48 hours and the galactomannan test was systematically repeated based on patient's clinical course. Even though the numbers in this study are very small, we report our experience about the role of early diagnosis and careful choice of antifungal therapy, considering the fragility of these patients, and its relationship with outcomes. Despite a systemic approach allowing early diagnosis and initiation of anti-fungal therapy, the mortality rate turned out to be very high (70%).

Enhanced dissolution of galactomannan and highly efficient selenium functionalization using ionic liquids with dual roles as solvents and catalysts

Galactomannan stands as a promising heteropolysaccharide, yet its randomly distributed non-linear structures and high molecular mass remain a huge challenge in solubilization and wide range of chemical modifications. This work develops a task specific approach for efficient dissolve of galactomannan in ionic liquids (ILs) by destructing and reconstructing intermolecular/intramolecular hydrogen bonds of galactomannan. Combining density functional theory calculations and experimental results, a reasonable mechanism of polysaccharide dissolution is proposed that the hydrogen bond networks of polysaccharide are broken, thus the hydroxyl groups are fully exposed and activated to facilitate functionalization. In view of the enhanced solubilization, an excellent effect in selenylation of galactomannan is notably improved by employing ILs with dual roles as solvents and catalysts. Typically, the introduction of -SO3H in ILs (SFILs) effectively enhances the protonation ability of selenium donor and thus further improves the functionalization efficiency. Furthermore, a surprising finding is observed that selenium content and average molecular mass of functionalized polysaccharide can be manipulated by the anions-cations synergistic effect which is highly dependent on SFILs acidity strength. This work proposed an integrated and promising strategy for improving the solubilization and functionalization manipulating by ILs, showing a great referential value for the widespread application in polysaccharide-rich resources.

Cassia fistula galactomannan stabilized copper nanocatalyst as an efficient, recyclable heterogeneous catalyst for the fast clickable [3+2] Huisgen cycloadditions in water

In this study, we have first time investigated the synthesis of copper nanocatalyst by using biopolymer galactomannan, naturally extracted from Cassia fistula pods. The methodology involved for the preparation of copper nanocatalyst is economical, efficient, environment friendly, and did not involve further processing for stabilization or reduction of copper nanoparticles. The morphology and structural characterization of the nanocatalyst was performed by using different techniques such as FT-IR, 1H NMR, SEM, EDX, HR-TEM, XRD, XPS, ICP-MS, BET, and TGA analysis. The prepared copper nanocatalyst is applied for the click [3+2] Huisgen cycloadditions of various azides and alkynes, employing water as environmentally benign solvent. In comparison to earlier reported methods, our method requires lowest catalyst loading, less reaction time, excellent yields and have wide substrate scope. Additionally, the catalyst was easily recovered by simple filtration and recycled at least ten consecutive times without any appreciable loss of efficiency and selectivity. The effect of mannose and galactose (Man/Gal) ratio of Cassia fistula galactomannan on the catalytic activity were also investigated.

Galactomannan polysaccharide as a biotemplate for the synthesis of zinc oxide nanoparticles with photocatalytic, antimicrobial and anticancer applications

Biotemplates provide a facile, rapid, and environmentally benign route for synthesizing various nanostructured materials. Herein, Locust Bean Gum (LBG), a galactomannan polysaccharide, has been used as a biotemplate for synthesizing ZnO nanoparticles (NPs) for the first time. The composition, structure, morphology, and bandgap of ZnO were investigated by Energy Dispersive X-ray Spectroscopy (EDX), X-Ray Photoelectron Spectroscopy (XPS), X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and UV-vis spectroscopy. XRD data showed single-phase crystalline hexagonal NPs. FTIR spectra confirmed the presence of M-O bonding in the sample. At a concentration of 0.5 mg/mL the NPs can degrade Rhodamine B under sunlight, displaying excellent photocatalytic activity. These NPs exhibited antimicrobial activity in both Staphylococcus aureus and Bacillus subtilis. Significant cell death was observed at 500 μg/mL, 250 μg/mL, 125 μg/mL and 62.5 μg/mL of NP in breast cancer, ovarian cancer and lung cancer cell lines. Wound healing assay showed that the NPs significantly blocked the cell migration at a concentration as low as 62.5 μg/mL in all three cell lines. Further optimization of the nanostructure properties will make it a promising candidate in the field of nano-biotechnology and bioengineering owing to its wide range of potential applications.

The protective immunity induced by Trichinella spiralis galectin against larval challenge and the potential of galactomannan as a novel adjuvant

Previous studies showed that recombinant Trichinella spiralis galectin (rTsgal) promoted larval invasion of gut epithelial cells, while anti-rTsgal antibodies inhibited the invasion. Galactomannan (GM) is a polysaccharide capable of regulating immune response. The aim of this study was to evaluate protective immunity induced by rTsgal immunization and the potential of GM as a novel adjuvant. The results showed that vaccination of mice with rTsgal+ISA201 and rTsgal+GM elicited a Th1/Th2 immune response. Mice immunized with rTsgal+ISA201 and rTsgal+GM exhibited significantly higher levels of serum anti-rTsgal antibodies, mucosal sIgA and cellular immune responses, but level of specific antibodies and cytokines of rTsgal+GM group was lower than the rTsgal+ISA201 group. Immunization of mice with rTsgal+ISA201 and rTsgal+GM showed a 50.5 and 40.16% reduction of intestinal adults, and 52.04 and 37.53% reduction of muscle larvae after challenge. Moreover, the numbers of goblet cells and expression level of mucin 2, Muc5ac and pro-inflammatory cytokines (TNF-α and IL-1β) in gut tissues of vaccinated mice were obviously decreased, while Th2 inducing cytokine (IL-4) expression was evidently increased. Galactomannan enhanced protective immunity, alleviated intestinal and muscle inflammation of infected mice. The results indicated that rTsgal+ISA201 vaccination induced a more prominent gut local as well as systemic immune response and protection compared to rTsgal+GM vaccination. The results suggested that Tsgal could be considered as a candidate vaccine target against Trichinella infection and galactomannan might be a potential novel candidate adjuvant of anti-Trichinella vaccines.

The Utility of Galactomannan and Polymerase Chain Reaction Assays in Bronchoalveolar Lavage for Diagnosis of Chronic Pulmonary Aspergillosis

The diagnosis of chronic pulmonary aspergillosis (CPA) is established by combined clinic-radio-microbiological criteria. Out of the different microbiological criteria, a positive serology for Aspergillus-specific IgG levels is the cornerstone of diagnosis. Alternatively, other microbiological evidence are sometimes sought viz., positive Aspergillus antigen (broncho-alveolar lavage fluid, i.e., BALF galactomannan ≥ 1.0), histopathological demonstration of the fungi following lung biopsy or resection, demonstration of hyaline septate hyphae in direct microscopy resembling Aspergillus spp. or its growth on a respiratory specimen. However, the exact roles of BALF- GM and the newer BALF-PCR have not been confirmed by studies till date. This study enrolled 210 patients with suspected CPA. Of the participants, 88 patients met the criteria for CPA, whereas 122 patients had an alternative diagnosis. The sensitivity-specificity of AsperGenius® PCR and "in-house" PCR were 52.27(36.69-67.54) %-33.78 (23.19-45.72) % and 36.36 (22.41-52.23) %-39.19 (28.04-51.23) % respectively. The sensitivity/specificity of BALF (> 1.0) and serum galactomannan (> 1.0) were 46.55% (33.34-60.13)/64.08% (54.03-73.3) and 29.82% (22.05-37.6)/86.84% (81.1-92.59) respectively. The optimal cut-off values for BALF-Galactomannan and serum galactomannan in diagnosing CPA were found to be 0.69 (sensitivity: 64%; specificity: 53%) and 0.458 (sensitivity: 67%; specificity: 64%) respectively. This results of this study suggests that Aspergillus PCR from BAL may not be a good "rule-in" test for diagnosing CPA. While the performances of GM in BAL and serum may be better than PCR, it should be best used in conjunction with other clinical, radiological, and other microbiological characteristics.

Microbiological diagnosis of pulmonary invasive aspergillosis in critically ill patients with severe SARS-CoV-2 pneumonia: a bronchoalveolar study

BACKGROUND

Diagnosing COVID-19-associated pulmonary aspergillosis (CAPA) can be challenging since radiological and clinical criteria in the critically ill patient are nonspecific. Microbiological diagnostic support is therefore crucial. The aim of this study was to document the incidence of aspergillosis using bronchoalveolar lavage (BAL) as the diagnostic method and to determine the performance of the current mycological diagnostic tests most widely used for the diagnosis of CAPA, together with evaluation of the Asp lateral flow device (LFD).

METHODS

Prospective cohort study conducted between March 2020 and June 2022. Inclusion criteria were critically ill patients admitted to the ICU with SARS-CoV-2 pneumonia requiring invasive mechanical ventilation. Diagnostic bronchoscopy and BAL were performed at the beginning of invasive mechanical ventilation. The sensitivity, specificity, positive and negative predictive value (PPV and NPV), positive and negative likelihood ratio (LR + and LR-) of BAL culture, direct examination with calcofluor white stain, ELISA (Platelia) and LFD (AspLFD) for detection of galactomannan (GM) were evaluated. Aspergillus-qPCR was applied when discrepancies between diagnostic tests arose.

RESULTS

Of the 244 critically ill patients with SARS-CoV-2 pneumonia admitted to the ICU, the majority (n = 200, 82%) required invasive mechanical ventilation. Diagnostic bronchoscopic procedures were performed in 160 patients (80%), who were enrolled in this study. The incidence of CAPA was 18.7% (n = 30). LFD-GM demonstrated a sensitivity of 84%, specificity of 99%, PPV 94%, NPV 97%, LR(+) of 84, and LR(-) of 0.16. At GM-ELISA indices of ≥ 0.5 and ≥ 1.0, sensitivity was 92% and 79%, specificity was 95% and 99%, PPV 76% and 91%, NPV 99% and 96%, LR(+) 18 and 79, and LR(-) 0.08 and 0.21, respectively. The optimal cut-off index from the ROC curve was 0.48, with sensitivity of 95% and specificity of 95%.

CONCLUSIONS

Using a diagnostic strategy based on bronchoscopy and BAL, we documented a high incidence of pulmonary aspergillosis in patients with severe SARS-CoV-2 pneumonia. Asp-LFD showed moderate sensitivity and excellent specificity, with a high PPV, and could be used for rapid diagnosis of patients with suspected CAPA.

Diagnostic Efficacy of Aspergillus Galactomannan Lateral Flow Assay in Patients with Hematological Malignancies: A Prospective Multicenter Study

BACKGROUND

A rapid and reliable diagnostic test is needed to reduce mortality through early diagnosis of invasive aspergillosis (IA) in patients with hematological malignancies.

OBJECTIVE

To evaluate the efficacy of serum and bronchoalveolar lavage (BAL) Aspergillus galactomannan lateral flow assay (GM-LFA) in IA diagnosis and determine the correlation of GM-LFA with GM enzyme immunoassay (GM-EIA) in patients with hematological malignancies.

METHODS

In this prospective multicenter study, we used serum and BAL fluid samples from patients with hematological malignancies and suspected IA and performed GM-LFA and GM-EIA. According to the EORTC/MSGERC criteria, patients were grouped as proven (n = 6), probable (n = 22), possible IA (n = 55), or no IA (n = 88). The performance of serum GM-LFA at 0.5 optical density index (ODI) and area under the curve (AUC) were calculated. Spearman's correlation analysis and kappa statistics were performed to determine the agreement between the tests.

RESULTS

GM-LFA showed an AUC of 0.832 in proven/probable IA (sensitivity [SEN], specificity [SPE], negative predictive value [NPV], and diagnostic accuracy were 75%, 100%, 92.6%, and 93.9%, respectively, at a 0.5 ODI) versus that in no IA. A moderate positive correlation was noted between the GM-LFA and GM-EIA scores (p = 0.01). The observed agreement between the tests at 0.5 ODI was almost perfect (p < 0.001). After excluding patients who received mold-active antifungal prophylaxis or treatment, the SEN, SPE, NPV, and diagnostic accuracy for proven/probable IA were 76.2%, 100%, 93.3%, and 94.5%, respectively.

CONCLUSIONS

Serum GM-LFA demonstrated high discriminatory power and good diagnostic performance for IA in patients with hematological malignancies.

Culture-independent diagnostic approaches for invasive aspergillosis in solid organ transplant recipients

Prompt and accurate diagnosis of invasive aspergillosis (IA) is crucial for immunocompromised patients, including those who have received a solid organ transplant (SOT). Despite their low sensitivity, microscopic detection and conventional culture are considered the 'gold standard' methods. In conjunction with conventional culture, culture-independent assays such as serum galactomannan testing and Aspergillus polymerase chain reaction (PCR) have been incorporated into the diagnostic process for IA. The recently revised consensus definitions from the European Organization for Research and Treatment of Cancer and the Mycosis Study Group have adjusted the threshold for positive galactomannan testing based on the sample type, and have excluded 1,3-β-D-glucan testing as a mycological criterion. Following extensive standardization efforts, positive Aspergillus PCR tests using serum, plasma, or bronchoalveolar lavage fluid have been added. However, there are limited studies evaluating the clinical utility of these culture-independent assays for the early diagnosis of IA in SOT recipients. Therefore, further research is required to determine whether these assays could aid in the early diagnosis of IA in SOT recipients, particularly in relation to the organ transplanted. In this review, we examine the culture-independent diagnostic methods for IA in SOT recipients, as well as the clinical utility of these assays.

Respiratory co-infections in COVID-19-positive patients

BACKGROUND

Opportunistic respiratory infections may complicate critically ill patients with COVID-19. Early detection of co-infections helps to administrate the appropriate antimicrobial agent, to guard against patient deterioration. This study aimed at estimating co-infections in COVID-19-positive patients.

METHODS

Eighty-nine COVID-19-positive patients confirmed by SARS-COV-2 PCR were tested for post-COVID-19 lower respiratory tract co-infections through bacterial culture, fungal culture and galactomannan (GM) testing.

RESULTS

Fourteen patients showed positive coinfection with Klebsiella, nine with Acinetobacter, six with Pseudomonas and three with E. coli. As for fungal infections, nine showed coinfection with Aspergillus, two with Zygomycetes and four with Candida. Galactomannan was positive among one patient with Aspergillus coinfection, one with Zygomycetes coinfection and three with Candida, 13 samples with negative fungal culture were positive for GM. Ten samples showed positive fungal growth, however, GM test was negative.

CONCLUSION

In our study, SARS-COV-2 respiratory coinfections were mainly implicated by bacterial pathogens; most commonly Klebsiella species (spp.), Aspergillus spp. were the most common cause of fungal coinfections, GM test showed low positive predictive value for fungal infection. Respiratory coinfections may complicate SARS-COV-2 probably due to the prolonged intensive care units (ICU) hospitalization, extensive empiric antimicrobial therapy, steroid therapy, mechanical ventilation during the COVID-19 outbreak. Antimicrobial stewardship programs are required so that antibiotics are prescribed judiciously according to the culture results.

Fluorescence probe technique for determining the hydrophobic interactions and critical aggregation concentrations of Gleditsia microphylla gum, circular Gleditsia sinensis gum, and tara gum

Circular Gleditsia sinensis gum, Gleditsia microphylla gum, and tara gum are galactomannans (GMs) with similar mannose/galactose (M/G) molar ratios, which complicates the characterization of physicochemical properties using conventional methods. Herein, the hydrophobic interactions and critical aggregation concentrations (CACs) of the GMs were compared using a fluorescence probe technique, in which the I1/I3 ratio of pyrene indicated polarity changes. With increasing GM concentration, the I1/I3 ratio decreased slightly in dilute solutions below the CAC but decreased sharply in semidilute solutions above the CAC, indicating that the GMs formed hydrophobic domains. However, increases in temperature destroyed the hydrophobic microdomains and increased the CACs. Higher concentrations of salts (SO42-, Cl-, SCN-, and Al3+) promoted hydrophobic microdomain formation, and the CACs in Na2SO4 and NaSCN solutions were lower than those in pure water. Hydrophobic microdomain formation also occurred upon Cu2+ complexation. Although urea addition promoted hydrophobic microdomain formation in dilute solutions, the microdomains were destroyed in semidilute solutions and the CACs increased. The formation or destruction of hydrophobic microdomains depended on the molecular weight, M/G ratio and galactose distribution of GMs. Therefore, the fluorescent probe technique enables the characterization of hydrophobic interactions in GM solutions, which can provide valuable insight into molecular chain conformations.

Extraction, characterization and biological activity of Galactomannan rich endosperm of Borassus flabellifer (Linn.) suitable for biofabrication of tissue scaffolds

The study deals with the isolation, purification and characterization of galactomannan from the endosperm of Borassus labellifer (Linn.) to be used for biomaterial fabrication in tissue engineering (TE) applications. The isolated Borassus flabellifer (Linn.) galactomannan (BFG) through a sequential aqueous dissolution, centrifugation and ethanol precipitation presented a total yield of 19.77 ± 1.05 % (w/w) with advantageous compositional and functional properties. BFG was found to have mannose to galactose (M/G) ratio of 1.4:1. The molecular weight of BFG was found to be 4.9 × 105 g/mol and the molecular structure analysis by FTIR and NMR spectroscopy revealed the presence of α-linked, d-galactopyranose units and β-linked, D-mannopyranose units. Further characterization by rheometer confirmed the non-Newtonian and pseudo-plastic behavior of different BFG concentrations and structural analysis by XRD and SEM confirmed the amorphous nature of BFG with the presence of pores and cervices on the rough surface. Finally, the favorable biological activity demonstrated in response to fibroblast cells against different BFG concentrations substantiates its relevance to be used in biofabrication of tissue scaffolds.

Use of fenugreek seed gum in edible film formation: major drawbacks and applicable methods to overcome

Researching on potential biopolymer sources with the aim of developing edible films with better mechanical and barrier properties has become innovative as it would be a key factor to minimize the use of synthetic polymers in food packaging. Therefore, different biopolymers such as galactomannan have been gaining attention recently. Fenugreek seed gum is a rich source of galactomannan which is minimally researched on its applicability in edible film making. The degree of galactose substitution and polymerization are the main factors that determine the functional properties of galactomannan. A strong and cohesive film matrix cannot be produced from fenugreek seed gum as its molecular interaction is weakened due to the high galactose substitution with a high galactose/mannose ratio, 1:1. Structural modifications of galactomannan in fenugreek seed gum will lead to films with the required mechanical properties. Hence, this review summarizes recent scientific studies on the limitations of fenugreek seed gum as a film forming agent and the specific modification techniques that can be applied in order to increase its film forming capability and performance.

Defluoridation of potable water employed by natural polysaccharide isolated from Tamarindus indica L

The current study evaluated the effectiveness of Tamarindus indica L. seed polysaccharides in removing fluoride from potable water collected from Sivakasi,Viruthunagar district, Tamil Nadu, India. The physiochemical properties of the water samples were examined, and each parameter was compared to the standard prescribed by Bureau of Indian standards. Most of the parameters were within the permissible limit except for fluoride levels in the Sivakasi water sample. Polysaccharides were isolated from Tamarindus indica L. seeds and the fluoride removal efficacy of the polysaccharides was evaluated. The optimum treatment dosage of the isolated seed polysaccharides was determined using aqueous fluoride solutions of various ppm concentrations (1, 2, 3, 4, and 5 ppm). Tamarindus polysaccharides were added to the aqueous solutions in varying doses (0.02, 0.04, 0.06, 0.08, 1.0, and 1.2 g), and 0.04 g was observed to be the most effective at removing fluoride (by 60%). It was selected as the optimum dose for treating the fluoride-contaminated water sample. Following the treatment, fluoride concentration in the water sample dropped from 1.8 mg/L to 0.91 mg/L, falling below the BIS standard limit. The findings from the study demonstrated the use of T. indica L. seed polysaccharides as an effective natural coagulant for removing fluoride from potable water. GC-MS and FTIR analysis of the isolated polysaccharide samples were performed. The FTIR results revealed the functional groups that might attribute to the fluoride removal activity of the isolated polysaccharides. The observations from the study suggested that Tamarindus polysaccharides might be used as an alternative to chemical agent used for fluoride removal in order to preserve the environment and human welfare.

Utility of Galactomannan Screening for Early Detection of Invasive Aspergillosis in High-Risk Hemato-Oncology Patients

INTRODUCTION

Invasive aspergillosis (IA) affects mainly patients with hematological malignancies, and early diagnosis is crucial for timely treatment. Most diagnoses are based on clinical and mycological criteria, mostly galactomannan (GM) test in serum or bronchoalveolar fluid, which is performed in case of clinical suspicion or as routine screening in patients at high risk who are not receiving anti-mold prophylaxis, for early detection of IA. The aim of this study was to assess in a real-world setting the efficacy of biweekly serum GM screening for the early detection of IA.

METHODS

A retrospective cohort that included 80 adult patients treated at the Hematology Department, Hadassah Medical Center, 2016-2020, with a diagnosis of IA. Clinical and laboratory data were collected from patients' medical files and the rate of GM-driven, GM-associated, and non-GM-associated IA was calculated.

RESULTS

There were 58 patients with IA. The rate of GM-driven diagnosis was 6.9%, GM-associated diagnosis was 43.1%, and non-GM-associated diagnosis was 56.9%. The GM test as a screening tool had led to IA diagnosis in only 0.2% of screened serums with a number needed to screen in order to find 1 patient with IA of 490.

CONCLUSION

Clinical suspicion outweighs GM screening as a tool for early diagnosis of IA. Nevertheless, GM has an important role as a diagnostic tool for IA.

A highly branched novel galactofuranan in the cell wall of Clavibacter tesselarius VKM Ac-1406T

The structures of two cell wall glycopolymers were studied in the plant pathogenic bacterium Clavibacter tesselarius VKM Ac-1406^T (family Microbacteriaceae, order Micrococcales, class Actinomycetes). The predominant polymer was a novel (1 → 6)-linked β-d-galactofuranan with a highly branched repeating unit, α-L-Rhap-(1 → 3)-α-D-Galp-(1 → 2)-[α-L-Rhap-(1 → 3)]-α-D-Fucp-(1 →, at O-2 on every second galactofuranose residue. The second polymer present in small amounts was acidic with the repeating unit, →3)-α-D-Galp-(1 → 3)-α-D-[4,6-S-Pyr]-Manp-(1 → 3)-α-D-Manp-[2OAc]_0.2-(1→, and was reported in all Clavibacter species investigated to date. The presented results expand our knowledges of structural diversity of phosphate-free cell wall glycopolymers and provide evidence in support of their taxonomic specificity for bacterial species and genera.

Developments in Fungal Serology

Purpose of Review

The true incidence of fungal disease is hampered by conventionally poor diagnostic tests, limited access to advanced diagnostics, and limited surveillance. The availability of serological testing has been available for over two decades and generally underpins the modern diagnosis of the most common forms of fungal disease. This review will focus on technical developments of serological tests for the diagnosis of fungal disease, describing advances in clinical performance when available.

Recent Findings

Despite their longevity, technical, clinical, and performance limitations remain, and tests specific for fungal pathogens outside the main pathogens are lacking. The availability of LFA and automated systems, capable of running multiple different tests, represents significant developments, but clinical performance data is variable and limited.

Summary

Fungal serology has significantly advanced the diagnosis of the main fungal infections, with LFA availability increasing accessibility to testing. Combination testing has the potential to overcome performance limitations.

Management of pulmonary aspergillosis in children: a systematic review

Invasive pulmonary aspergillosis (IPA) is a severe condition in immunocompromised children, but the optimal management is still under debate. In order to better clarify this issue, a literature search was performed through MEDLINE/PubMed database to describe current risk factors and diagnostic, therapeutic and prophylactic tools for invasive pulmonary aspergillosis (IPA) in the paediatric age. Observational studies and clinical trials regarding diagnosis, treatment and prophylaxis were considered, and results were summarised. Five clinical trials and 25 observational studies (4453 patients) were included.Haematological malignancies, previous organ transplant and other primary or acquired immunodeficiency were identified as risk factors for IPA in children.Current diagnostic criteria distinguish between "proven", "probable" and "possible" disease. Consecutive galactomannan assays have good sensitivity and specificity, especially when performed on broncho-alveolar lavage. At the same time, β-D-glucan should not be used since cut-off in children is unclear. PCR assays cannot currently be recommended for routine use.Voriconazole is the recommended first-line agent for IPA in children older than 2 years of age. Liposomal amphotericin B is preferred in younger patients or cases of intolerance to voriconazole. Its plasma concentrations should be monitored throughout the treatment. The optimal duration of therapy has yet to be determined. Posaconazole is the preferred prophylactic agent in children older than 13 years old, whereas oral voriconazole or itraconazole are the drugs of choice for those between 2-12 years. Further good-quality studies are warranted to improve clinical practice.

Evaluation of the EUROIMMUN Aspergillus antigen immunoenzyme assay in serum and bronchoalveolar lavage fluid samples

INTRODUCTION

The most widely used marker for the diagnosis of invasive aspergillosis (IA) is the detection of galactomannan by ELISA. This study describes the evaluation of the results obtained by Euroimmun Aspergillus antigen ELISA (EIA-GM-E) in serum samples and bronchoalveolar lavage fluid (BAL) from patients at risk of IA, and compares these results with those obtained by Bio-Rad Galactomannan EIA (EIA-GM-BR).

METHODS

Anonymous retrospective case-control comparative study in 64 serum samples and 28 BAL from 51 patients.

RESULTS

Overall agreement of the results of the two assays was observed in 72 of 92 samples (78.3%). The sensitivity of EIA-GM-BR and EIA-GM-E in serum samples was 88.9% and 43.2%, respectively, and 100% and 88.9% for BAL. The specificity of EIA-GM-BR and EIA-GM-E in serum samples was 91.9% for both assays, and 68.4% and 84.2% in BAL. There were no statistically significant differences in the results of both assays.

CONCLUSIONS

Both methods show good results for the discrimination of patients with IA when BAL is tested, or serum in case of EIA-GM-BR.

Performance of galactomannan testing from endotracheal aspirate to guide bronchoalveolar lavage in the diagnosis of invasive aspergillosis

PURPOSE

Invasive aspergillosis is a major threat to immunocompromised individuals. Galactomannan (GM) is used as a biomarker for invasive aspergillosis. Investigations recommended in current guidelines include GM testing of bronchoalveolar lavage (BAL) fluids. GM testing of endotracheal aspirate, the sampling of which is less invasive, less resource-intensive and less aerosol-generating, is not validated. We compared the performance of endotracheal aspirate GM as a screening tool to predict BAL fluid GM-positivity in patients with suspected invasive aspergillosis.

METHODS

Of each patient, a pair of corresponding endotracheal aspirate and BAL fluid samples was tested and compared for GM results. Two sample sets were included. The first consisted of 140 consecutive BAL fluid/endotracheal aspirate pairs obtained from 133 patients. The pairs of the second sample set (n = 38) were selected based on the criterion that the BAL tested positive for GM. All specimens were obtained in a German 2,000 bed tertiary care center.

RESULTS

Among BAL fluid GM-positive samples, endotracheal aspirate GM demonstrated poor specificity (72%) but high sensitivity (92% in predicting BAL fluid GM of ≥ 0.50 and 91% for BAL fluid GM of ≥ 1.00) and an excellent negative predictive value (98%). The use of a marginally elevated cutoff of 0.63 resulted in an improved specificity (72-81%), without loss of sensitivity.

CONCLUSIONS

For screening purposes, one might consider testing endotracheal aspirate for GM, which could help avoid unnecessary BAL.

Properties of galactomannans and their textile-related applications-A concise review

Galactomannans are reserve carbohydrates in legume plants and are primarily extracted from their seeds. They contain galactose side chains throughout the mannose backbone and have unique features such as emulsifying, thickening, and gelling together with biodegradability, biocompatibility, and non-toxicity, which make them an appealing material. Guar gum and locust bean gum mainly are used in all galactomannan needed applications. Nonetheless, tara gum and fenugreek gum have also attracted considerable attention in recent decades. Despite the increased usage of galactomannans in the textile-related fields in recent years, there is no review article published yet. To fill this gap and to demonstrate the striking and increasing importance of galactomannans, a concise summary of the properties of common galactomannans and their comparisons is given first, followed by an account of recent developments and applications of galactomannans in the textile-related fields. The associated potential opportunities are also provided at the end of this review.

Review: bioavailability and efficacy of 'free' curcuminoids from curcumagalactomannoside (CGM) curcumin formulation

The golden spice turmeric with its main bioactive component curcumin is one of the most popular and extensively studied nutraceuticals. Despite numerous pre-clinical studies reporting positive pharmacodynamics of turmeric extracts and curcumin, the main issues in translating the pharmacological effects to clinical efficacy have been to overcome its poor pharmacokinetics and to deliver significant amounts of the biologically relevant forms of the actives to various tissues. This review is aimed at providing a first critical evaluation of the current published literature with the novel curcumagalactomannoside (CGM) formulation of curcumin using fenugreek galactomannan dietary fibre, specifically designed to address curcumin poor pharmacokinetics. We describe CGM and its technology as a food-grade formulation to deliver 'free' unconjugated curcuminoids with enhanced bioavailability and improved pharmacokinetic properties. The therapeutic relevance of improving bioavailability of 'free' curcuminoids and some of the technical challenges in the measurement of the 'free' form of curcuminoids in plasma and tissues are also discussed. A total of twenty-six manuscripts are reviewed here, including fourteen pre-clinical and twelve clinical studies that have investigated CGM pharmacokinetics, safety and efficacy in various animal models and human conditions. Overall current scientific evidence suggests CGM formulation has improved bioavailability and tissue distribution of the biologically relevant unconjugated forms of turmeric actives called 'free' curcuminoids that may be responsible for the superior clinical outcomes reported with CGM treatments in comparison with unformulated standard curcumin across multiple studies.

Synergistic studies of Cassia tora gum with xanthan and guar gum: Carboxymethyl synthesis of cassia gum-xanthan synergistic blend and characterization

The present study describes the study of synergistic behavior of the Cassia tora (CTG) gum with xanthan gum (XG) and comparison with CTG and guar gum (GG) at varying temperatures. A carboxymethyl derivative of CTG: XG blend, having synergistic activity was synthesized and the reaction conditions were optimized using Taguchi's L'9 statistical design. The effect of solvent medium on the degree of substitution (DS) and the gelling property was also studied. The results reveal that synergistic interaction was found in the CTG: XG mixture whereas CTG: GG blend did not show synergistic behavior. The CTG: XG blend shows a highly viscous solution having 8371.9 cps viscosity at ambient temperature and gel is obtained by heating the blending solution and thereafter lowering the temperature. In continuum, an optimized carboxymethyl derivative (DS 0.16) also exhibits gelling properties. The carboxymethyl derivative was characterized by ¹H NMR, FTIR spectroscopy and FESEM analysis. The synergistic action of gums may be utilized in food, cosmetics and pharmaceutical applications.

The lipid-lowering effects of fenugreek gum, hawthorn pectin, and burdock inulin

Objective

The present study aimed to investigate the lipid-lowering effects and mechanisms of fenugreek gum (FG), hawthorn pectin (HP), and burdock inulin (BI) on high-fat diet (HFD)-induced hyperlipidemic rats.

Methods

In this study, high-fat diet (HFD) together with fat emulsion administration were used to establish hyperlipidemia model. The biochemical indices were assayed after administration of FG, HP, and BI. Their effects were evaluated by factor analysis. Alterations of gut microbiota and short chain fatty acids (SCFAs) in the cecal were assessed to illustrate the mechanism of lipid lowering.

Results

The supplementation of FG, HP, and BI on HFD-fed rats decreased the levels of serum lipid and reduced the HFD-related liver and testicle damage. In the scatter plot of factor analysis, HP and BI were closer to normal fat diet (NFD) group in restoring the severity of hyperlipidemia, while FG and HP enhanced the excretion of cholesterol and bile acids (BAs). The levels of total SCFAs, especially butyric acid reduced by HFD were increased by HP. The ratio of Firmicutes to Bacteroidetes increased by HFD was reduced by HP and BI. FG, HP, and BI enriched intestinal probiotics, which were related to bile acid excretion or lipid-lowering.

Conclusions

FG inhibited the absorption of cholesterol and enhanced the excretion of it, as well as increased the abundance of beneficial bacteria. While BI restored the imbalance of intestinal microbiota. HP enhanced the excretion of cholesterol and BAs, and restored the imbalance of intestinal microbiota. It was also utilized by intestinal microorganisms to yield SCFAs. This study suggested that FG, HP, and BI possessed the potential to be utilized as dietary supplements for obesity management.

Sustainable biopolymer soil stabilisation: the effect of microscale chemical characteristics on macroscale mechanical properties

Sustainable biopolymer additives offer a promising soil stabilisation methodology, with a strong potential to be tuned to soil's specific nature, allowing the tailoring of mechanical properties for a range of geotechnical applications. However, the biopolymer chemical characteristics driving soil mechanical property modifications have yet to be fully established. Within this study we employ a cross-scale approach, utilising the differing galactose:mannose (G:M) ratios of various Galactomannan biopolymers (Guar Gum G:M 1:2, Locust Bean Gum G:M 1:4, Cassia Gum G:M 1:5) to investigate the effect of microscale chemical functionality upon macroscale soil mechanical properties. Molecular weight effects are also investigated, utilising Carboxy Methyl Cellulose (CMC). Soil systems comprising of SiO2 (100%) (SiO2) and a Mine Tailing (MT) exemplar composed of SiO2 (90%) + Fe2O3 (10%) (SiO2 + Fe) are investigated. The critical importance of biopolymer additive chemical functionality for the resultant soil mechanical properties, is demonstrated..For Galactomannan G:M 1:5 stabilised soils the 'high-affinity, high-strength', mannose-Fe interactions at the microscale (confirmed by mineral binding characterisation) are attributed to the 297% increase in the SiO2 + Fe systems Unconfined Compressive Strength (UCS), relative to SiO2 only. Conversely for SiO2 Galactomannan-stabilised soils, when increasing the G:M ratio from 1:2 to 1:5, a 85% reduction in UCS is observed, attributed to mannose's inability to interact with SiO2. UCS variations of up to a factor of 12 were observed across the biopolymer-soil mixes studied, in line with theoretically and experimentally expected values, due to the differences in the G:M ratios. The limited impact of molecular weight upon soil strength properties is also shown in CMC-stabilised soils. When considering a soil's stiffness and energy absorbance, the importance of biopolymer-biopolymer interaction strength and quantity is discussed, further deciphering biopolymer characteristics driving soil property modifications. This study highlights the importance of biopolymer chemistry for biopolymer stabilisation studies, illustrating the use of simple low-cost, accessible chemistry-based instrumental tools and outlining key design principles for the tailoring of biopolymer-soil composites for specific geotechnical applications.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s11440-022-01732-0.

Impact of revised EORTC/MSGERC 2020 criteria on diagnosis and prognosis of invasive pulmonary aspergillosis in patients with hematological malignancies undergoing bronchoscopy

INTRODUCTION

The first consensus definitions for invasive fungal diseases (IFD) were published in 2002. Advances in diagnostic tests and a clear need for improvement in certain areas led to a revision of these definitions in 2008. However, growing data on Aspergillus galactomannan (GM) thresholds and the introduction of new polymerase chain reaction-based diagnostic tests resulted in a further update by EORTC and Mycoses Study Group Education and Research Consortium (MSGERC) in 2020. Compared to the 2008 version, the 2020 EORTC/MSGERC criteria have stricter definitions, especially regarding GM levels, which should lead to improved specificity. Thus, our study aimed to evaluate diagnostic changes, based on GM levels, resulting from these new definitions and ascertain the impact of the new classification on mortality rates.

METHOD

Patients hospitalized in a single tertiary care center with hematologic malignancies and undergoing bronchoscopy for suspected IPA between April 2004 and December 2019 were included in this retrospective study.

RESULTS

The study population consisted of 327 patients with 31 patients (nine patients with proven IPA and 22 patients with no IPA) excluded from the study. 194 patients were classified as probable IPA cases according to 2008 EORTC/MSG criteria. However, 53 (27.3%) of these patients were re-classified as possible IPA according to 2020 EORTC/MSGERC criteria, due to novel galactomannan cut-off levels. Compared to re-classified possible IPA patients, those remaining in the probable IPA category experienced a higher incidence of septic shock (34.0% vs 16.9%, p=0.02), and required more non-invasive (12.0% vs 0.0%, p=0.004) and invasive (44.6 vs 24.5%, p=0.01) mechanical ventilation. There was a higher in-hospital mortality rate in probable IPA patients than in the re-classified possible IPA group (42.5% vs 22.6%, p=0.01). Patients reassigned to possible IPA had similar underlying diseases, radiological features and prognosis to patients already classified as possible IPA. Independent risk factors for mortality were classification as probable IPA according to 2020 EORTC/MSGERC criteria, lack of remission from hematologic malignancy, and number of nodules in Thorax CT.

CONCLUSION

The use of 2020 EORTC/MSGERC criteria resulted in a 27.3% significant reduction in probable IPA diagnoses and created a more homogeneous category of patients with respect to treatment response, prognosis and mortality. Therefore, 2020 EORTC/MSGERC criteria afford more reliable mortality prediction than 2008 EORTC/MSG criteria.

modulate galectin-8-mediated bioactivity

Polysaccharides from fungi have many bioactivities. Previous studies showed that galactomannans from Penicillium oxalicum antagonize galectin-8-mediated activity. Here, two intracellular and two extracellular galactomannans were purified and their structures were comparatively characterized by NMR, partial acid hydrolysis and methylation. All four of them were identified to be galactomannans with similar mannan backbones having 1,2-/1,6-linkages (~3:1) and various amounts of galactofuranan side chains. The interaction of those polysaccharides with galectin-8 was assessed by hemagglutination and biolayer interferometry. These results show that side chains are important for the interaction, and the more the side chains, the stronger the interaction. But the side chains alone did not show act on galectin-8, which indicated that the cooperation between backbone and side chains is another necessary factor for this interaction. Our findings provide important information about structure-activity relationships and the galactofuranose-containing galactomannans might be as potential therapeutic of galectin-8 related diseases.

Interpretation, pitfalls of biomarkers in diagnosis of invasive fungal diseases

BACKGROUND

Invasive Fungal Diseases (IFD), account for high morbidity and mortality in immunocompromised and seriously ill patients worldwide. Early, faster and accurate diagnosis with timely and appropriate patient management is critical for improved patient outcome and antifungal stewardship. Clinical/radiological presentations in IFD are non-specific and microscopy/culture based tests have low sensitivity and long turnaround time. Biomarkers have clinical utility for diagnosing IFD but their interpretation is not straight forward.

OBJECTIVES

This review discusses the salient characteristics, clinical usefulness and limitations of common biomarkers such as Galactomannan (GM), 1-3, β D glucan (βDG), mannan, anti-mannan antibody (Mn/antiMn), Cryptococcal antigen test (CrAg), Nucleic Acid Amplification (NAA) tests and next generation sequencing for diagnosing IFD.

CONTENTS

Fungal biomarkers are useful adjuncts as screening and diagnostic tools for IFD and are much more suited for 'ruling out' rather than 'ruling in' disease. GM, NAA tests are promising biomarkers for screening of invasive Aspergillosis in high risk asymptomatic patients who are not on antifungal therapy and for diagnosis of breakthrough infections in symptomatic patients. 1-3, β D glucan has limitations both as a 'rule in' and 'rule out' test and is useful in only specific clinical settings. Two consecutive positive 1-3-βDG tests or combined positivity with GM increases its specificity. Mn/antiMn, T2Candida nano diagnostic panel are promising candidates for diagnosing invasive candidiasis. Combining two or more biomarkers improves the sensitivity for prompt initiation of antifungal therapy and the negative predictive value for suspension of empirical treatment. Serum CrAg test is a good 'rule in' rather than a 'rule out' test in immunocompetent patients but has good diagnostic accuracy in immunocompromised patients. Detection of single nucleotide polymorphisms by next generation sequencing is useful for fungal characterization and identification of host determinants responsible for increased susceptibility to fungal infections but is still in experimental stages.

Serum galactomannan in histoplasmosis in HIV

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

Combinatorial assembly and optimisation of designer cellulosomes: a galactomannan case study

BACKGROUND

Designer cellulosomes are self-assembled chimeric enzyme complexes that can be used to improve lignocellulosic biomass degradation. They are composed of a synthetic multimodular backbone protein, termed the scaffoldin, and a range of different chimeric docking enzymes that degrade polysaccharides. Over the years, several functional designer cellulosomes have been constructed. Since many parameters influence the efficiency of these multi-enzyme complexes, there is a need to optimise designer cellulosome architecture by testing combinatorial arrangements of docking enzyme and scaffoldin variants. However, the modular cloning procedures are tedious and cumbersome.

RESULTS

VersaTile is a combinatorial DNA assembly method, allowing the rapid construction and thus comparison of a range of modular proteins. Here, we present the extension of the VersaTile platform to facilitate the construction of designer cellulosomes. We have constructed a tile repository, composed of dockerins, cohesins, linkers, tags and enzymatically active modules. The developed toolbox allows us to efficiently create and optimise designer cellulosomes at an unprecedented speed. As a proof of concept, a trivalent designer cellulosome able to degrade the specific hemicellulose substrate, galactomannan, was constructed and optimised. The main factors influencing cellulosome efficiency were found to be the selected dockerins and linkers and the docking enzyme ratio on the scaffoldin. The optimised designer cellulosome was able to hydrolyse the galactomannan polysaccharide and release mannose and galactose monomers.

CONCLUSION

We have eliminated one of the main technical hurdles in the designer cellulosome field and anticipate the VersaTile platform to be a starting point in the development of more elaborate multi-enzyme complexes.

Evaluation of the diagnostic accuracy of galactomannan from the bronchoalveolar lavage fluid of patients with suspected invasive pulmonary aspergillosis

BACKGROUND

Several studies to evaluate the accuracy of galactomannan (GM) in bronchoalveolar lavage fluid (BALF) as a diagnostic tool have been carried out; however, there are still controversies about the optimal cut-off point of BALF GM.

AIMS

The objective of this study was to determine the diagnostic accuracy and the optimal cut-off point on BALF GM from patients with suspected invasive pulmonary aspergillosis (IPA) in a tertiary care hospital.

METHODS

A cross-sectional study with 188 patients (≥18 years) that had undergone a bronchoscopy with BAL due to suspected IPA was carried out. IPA was diagnosed according to the EORTC/MSG guidelines.

RESULTS

The optimal optical density cut-off point for BALF GM was 0.67, with sensitivity, specificity, positive predictive value, and negative predictive value of 100%, 70%, 32.3%, and 100%, respectively.

CONCLUSIONS

BALF GM detection proved to be a useful supplementary technique in the early diagnosis of IPA in both neutropenic and non-neutropenic patients.

The immunomodulatory activity of degradation products of Sesbania cannabina galactomannan with different molecular weights

Galactomannan (GM) is widely recognized as an immune enhancer; however, the underlying molecular mechanism is still unknown. Herein, four products with molecular weights in descending order, namely GM40, GM50, GM65, and GMOS, were separated from incomplete degradation products of Sesbania cannabina GM by ethanol precipitation, followed by their immunomodulatory activity. Through FTIR and XPS spectra, the amount of free hydroxyl groups was shown to decrease in the following order: GM > GM50 > GMOS > GM40 > GM65. Moreover, the immunomodulatory activity of different products decreased in abovementioned order. The TNF-α, IL-6 and TLR4 content in RAW 264.7 cells treated with different GM products in the presence or absence of TAK-242 (TLR4 inhibitor) suggested that the immunomodulatory activity of GM and its degradation products is TLR4-dependent. Overall, the preliminary relationship indicated here between the hydroxyl groups or the possible deeper structural changes of GM and the immunomodulatory activity need to be further investigated.

Polysaccharide-based formulations as potential carriers for pulmonary delivery - A review of their properties and fates

Polysaccharides can be elite carriers for therapeutic molecules due to their versatility and low probability to trigger toxicity and immunogenic responses. Local and systemic therapies can be achieved through particle pulmonary delivery, a promising non-invasive alternative. Successful pulmonary delivery requires particles with appropriate flowability to reach alveoli and avoid premature clearance mechanisms. Polysaccharides can form micro-, nano-in-micro-, and large porous particles, aerogels, and hydrogels. Herein, the characteristics of polysaccharides used in drug formulations for pulmonary delivery are reviewed, providing insights into structure-function relationships. Charged polysaccharides can confer mucoadhesion, whereas the ability for specific sugar recognition may confer targeting capacity for alveolar macrophages. The method of particle preparation must be chosen considering the properties of the components and the delivery device to be utilized. The fate of polysaccharide-based carriers is dependent on enzyme-triggered hydrolytic and/or oxidative mechanisms, allowing their complete degradation and elimination through urine or reutilization of released monosaccharides.

COVID-19-associated pulmonary aspergillosis in a tertiary care center in Shenzhen City

Objectives

The severe coronavirus disease 2019 (COVID-19) is characterized by acute respiratory distress syndrome (ARDS) and risk of fungal co-infection, pulmonary aspergillosis in particular. However, COVID-19 associated pulmonary aspergillosis (CAPA) cases remain limited due to the difficulty in diagnosis.

Methods

We describe presumptive invasive aspergillosis in eight patients diagnosed with COVID-19 in a single center in Shenzhen, China. Data collected include underlying conditions, mycological findings, immunodetection results, therapies and outcomes.

Results

Four of the eight patients had tested positive for Aspergillus by either culture or Next-generation sequencing analysis of sputum or bronchoalveolar lavage fluid (BALF), while the rest of patients had only positive results in antigen or antibody detection. Although all patients received antifungal therapies, six of these eight patients (66.7%) died.

Conclusion

Due to the high mortality rate of CAPA, clinical care in patients with CAPA deserves more attention.

The role of pentraxin3 in plasma and bronchoalveolar lavage fluid in COPD patients with invasive pulmonary aspergillosis

Background

The use of galactomannan (GM) testing in plasma and bronchoalveolar lavage fluid (BALF) has improved the diagnosis of invasive pulmonary aspergillosis (IPA) in patients with chronic obstructive pulmonary disease (COPD); however, the high false-positive rate leads to overdiagnosis. Pentraxin 3 (PTX3) as an indicator of inflammation plays an important role in resistance to Aspergillus infections. This study aimed to investigate the diagnostic value of PTX3 for diagnosing IPA with COPD.

Methods

We retrospectively collected data on patients with suspected COPD and IPA who had been hospitalized in the Third Affiliated Hospital of Soochow University between September 2017 and November 2020. PTX3 and GM were measured using enzyme-linked immunosorbent assays.

Results

A total of 165 patients were included in the study, of whom 35 had confirmed or probable IPA. The remaining 130 patients served as controls. The median plasma and BALF PTX3 levels were significantly higher in patients with IPA than in control patients (3.74 ng/mL vs. 1.29 ng/mL, P < 0.001; and 3.88 ng/mL vs. 1.58 ng/mL, P < 0.001 in plasma and BALF, respectively). The plasma GM, plasma PTX3, BALF GM, and BALF PTX3 assays had sensitivities of 60.0%, 77.1%, 78.6%, and 89.3%, respectively, and specificities of 73.8%, 69.2%, 80.7%, and 77.1%, respectively. The sensitivity of PTX3 in plasma and BALF was higher than that of GM. However, the specificity of PTX3 and GM did not differ significantly between the IPA group and the control group. The specificity of the assays for the diagnosis of IPA was > 90% in patients who were PTX3-positive and GM-positive in plasma and BALF.

Conclusions

BALF and plasma PTX3 levels were significantly higher in COPD patients with IPA. The sensitivity of PTX3 was superior to that of GM for diagnosing IPA in patients with COPD. The combination of GM and PTX3 is useful for the diagnosis of IPA in patients with COPD.

Cerebral aspergillosis in the era of new antifungals: The CEREALS national cohort study Nationwide CEREbral Aspergillosis Lesional study (CEREALS)

BACKGROUND

Cerebral aspergillosis (CA) is a life-threatening disease for which diagnosis and management remain challenging. Detailed analyses from large cohorts are lacking.

METHODS

We included 119 cases of proven (n = 54) or probable (n = 65) CA diagnosed between 2006 and 2018 at 20 French hospitals. Data were collected at baseline and during follow-up. Cerebral imaging was reviewed centrally by two neuroradiologists.

RESULTS

The most frequent underlying conditions were hematological malignancy (40%) and solid organ transplantation (29%). Galactomannan was detected in the serum of 64% of patients. In 75% of cases, at least one of galactomannan, Aspergillus PCR, and β-d-glucan was positive in the cerebrospinal fluid. Six-week mortality was 45%. Two distinct patterns of disease were identified according to presumed route of dissemination. Presumed haematogenous dissemination (n = 88) was associated with a higher frequency of impaired consciousness (64%), shorter time to diagnosis, the presence of multiple abscesses (70%), microangiopathy (52%), detection of serum galactomannan (69%) and Aspergillus PCR (68%), and higher six-week mortality (54%). By contrast, contiguous dissemination from the paranasal sinuses (n = 31) was associated with a higher frequency of cranial nerve palsy (65%), evidence of meningitis on cerebral imaging (83%), macrovascular lesions (61%), delayed diagnosis, and lower six-week mortality (30%). In multivariate analysis and in a risk prediction model, haematogenous dissemination, hematological malignancy and the detection of serum galactomannan were associated with higher six-week mortality.

CONCLUSION

Distinguishing between hematogenous and contiguous dissemination patterns appears to be critical in the workup for CA, as they are associated with significant differences in clinical presentation and outcome.

Guar (Cyamopsis tetragonoloba L.) plant gum: From biological applications to advanced nanomedicine

Natural polymers are an efficient class of eco-friendly and biodegradable polymers, because they are readily available, come from natural sources, inexpensive and can be chemically modified with the correct reagents. Guar gum (GG) is a natural polymer with great potential to be used in pharmaceutical formulations due to its unique composition and lack of toxicity. GG can be designed to suit the needs of the biological and medical engineering sectors. In the development of innovative drug delivery systems, GG is commonly utilized as a rate-controlling excipient. In this review, different properties of GG including chemical composition, extraction methods and its usefulness in diabetes, cholesterol lowering, weight control, tablet formulations as well as its food application were discussed. The other purpose of this study is to evaluate potential use of GG and its derivatives for advanced nanomedicine such as drug delivery, tissue engineering and nanosensing. It should be noted that some applicable patents in medical area have also been included in the rest of this survey to extend knowledge about guar gum and its polymeric nature.

Cell wall galactofuranan and pyruvate-containing galactomannan in the cell walls of Clavibacter strains

The cell wall glycopolymer structures of plant-associated strains Clavibacter sp. VKM Ac-1371, Clavibacter sp. VKM Ac-1372 and Clavibacter sp. VKM Ac-1374, members of three putative new species (family Microbacteriaceae, class Actinobacteria) were studied. Each strain was found to contain two glycopolymers, neutral and acidic ones. The main chain of neutral polymer, identical in all three strains, is (1 → 6)-linked β-d-galactofuranan with every second galactofuranose residue substituted at position 2 by side disaccharide, α-d-Manp-(1 → 2)-α-d-Ribf-(1 → . The second, acidic polymer, is pyruvate-containing galactomannan with the repeating unit, →3)-α-d-Galp-(1 → 3)-α-d-[4,6-S-Pyr]-Manp-(1 → 3)-α-d-Manp-(1 → . Reducing mannopyranose residues of the acidic polysaccharides repeating unit from strains VKM Ac-1372 and VKM Ac-1374 bear O-acetyl residues additionally. The cell wall glycopolymer structures were established by chemical and NMR spectroscopic methods with using one- and two-dimensional techniques ¹H,¹H COSY, TOCSY, ROESY and ¹H,¹³C HSQC, HMBC. The results obtained provide new data on diversity of the bacterial cell wall glycopolymers and may prove valuable for microbial taxonomy and insight into the molecular mechanisms of interactions between bacteria and plants and also of bacterial adaptation to survival in desert systems.

Temozolomide is a risk factor for invasive pulmonary aspergillosis: A case report and literature review

BACKGROUND

Temozolomide is an oral alkylating agent incorporated in the treatment of glioblastoma multiforme (GBM) that can lead to lymphopenia. The standard treatment of GBM involves temozolomide chemotherapy with radiation, often with addition of corticosteroids for symptomatic management of cerebral edema. Some studies have reported an increased risk of opportunistic infections.

CASE PRESENTATION

A 72-year-old man receiving Temozolomide for treatment of newly diagnosed GBM associated with radiotherapy and corticosteroids was admitted in an intensive care unit because a rapid deterioration of consciousness associated with acute respiratory failure. The diagnosis of invasive pulmonary aspergillosis (IPA) was made. The patient was successfully treated with voriconazole alone.

CONCLUSIONS

This case shows that Temozolomide can be associated with severe invasive aspergillosis, which is in all likelihood associated with T lymphocyte immune dysfunction. Physicians should be aware of possible opportunistic infections when managing patients with glioblastoma, and patients exposed to this agent should be carefully monitored.

Invasive aspergillosis in critically ill patients: Review of definitions and diagnostic approaches

Invasive aspergillosis (IA) is an increasingly recognised phenomenon in critically ill patients in the intensive care unit, including in patients with severe influenza and severe coronavirus disease 2019 (COVID-19) infection. To date, there are no consensus criteria on how to define IA in the ICU population, although several criteria are used, including the AspICU criteria and new consensus criteria to categorise COVID-19-associated pulmonary aspergillosis (CAPA). In this review, we describe the epidemiology of IA in critically ill patients, most common definitions used to define IA in this population, and most common clinical specimens obtained for establishing a mycological diagnosis of IA in the critically ill. We also review the most common diagnostic tests used to diagnose IA in this population, and lastly discuss the most common clinical presentation and imaging findings of IA in the critically ill and discuss areas of further needed investigation.

Selective extraction of galactomannan from fenugreek (Trigonella foenum-graecum L.) seed husk and its enzyme inhibitory potential associated with hyperglycaemia

BACKGROUND

Fenugreek seeds host various bioactive compounds, and galactomannan (GM) is a significant soluble fibre. In this study, selective extraction is adapted to extract fenugreek seed GM to improvise the yield recovery. The seeds are fractionated, separated and classified as husk and cotyledons. Comparative studies have been performed to evaluate the crude and pure GM yield between different groups such as the whole seed, and the classified fractions. Characterization is done using Fourier transform infrared, differential scanning calorimetry, scanning electron microscopy, monosaccharide composition and optical density, and the structure is elucidated through nuclear magnetic resonance. The GM obtained through extraction is used to study its enzyme inhibitory property associated with hyperglycaemia.

RESULTS

GM yield extracted from the husk is highly significant compared to other groups. Crude GM and pure GM yield was 2 and 3.25 times higher than that obtained through whole seed samples. The characterization of the pure GM is on a par with the existing reports. The purified GM inhibited α-amylase and α-glucosidase enzymes in vitro, with an IC50 of 21.08 ± 0.085 and 67.17 ± 5.15 μg mL^-1 , respectively.

CONCLUSION

Selective extraction prompts enhancement in the recovery of the bioactive compound, minimal use of resources, and promotes industrial viability. Characterization of the compound confirms the structure. Its enzyme inhibitory property makes GM a valuable compound in diabetic prevention/treatment. © 2021 Society of Chemical Industry.

Effects of the Hofmeister anion series salts on the rheological properties of Sesbania cannabina galactomannan

Sesbania cannabina galactomannan (2%) solutions added with strongly hydrated ions (Na₂CO₃, NaH₂PO₄, NaCl) and weakly hydrated ions (NaNO₃) at different ionic strengths were rheologically characterized. The four selected salts dramatically decreased the intrinsic viscosity of galactomannan solution in the following order of effectiveness: Na₂CO₃ < NaH₂PO₄ < NaCl < NaNO₃. This conforms effectively to the Hofmeister anion series. Moreover, salt addition increased the viscosity of galactomannan solution when the ionic strength was 1 mmol/kg, which related to an increased occurrence of intermolecular interactions. As increasing ionic strength, galactomannan chains may tend to contract or expand due to the presence of strongly or weakly hydrated ions, thereby decreasing the viscosity. These phenomena were demonstrated by zeta potential measurement and again observed in dynamic viscoelasticity measurement. Overall, this property can be used to manipulate the rheological properties of galactomannan in food gums to obtain gums of high quality for enhancing consumer goods.