Aspergillus Conidia Research Articles

Airborne pollen and spore monitoring for seasonal trends and dynamic interconnection with meteorological parameters in Rawalpindi city, Pakistan

Aerobiological studies are essential to understand the pollen and spore diversity and allergy hazards. Airborne pollen/spore assemblages seasonally and regionally are affected by weather variables. Local vegetation plays an integral role in atmospheric pollen loads. This study identified the pollen taxa families and spore types in conjunction with influencing meteorological parameters e.g. temperature, rainfall, wind speed, relative humidity. Daily airborne pollen and spore were monitored to estimate seasonal diversity and intensity (measured in grains/m3) by using volumetric method throughout the year 2023. Daily weather updates and monthly reports of Pakistan Meteorological Department were assessed to collect meteorological data. Results revealed that pollen and spore concentration were low in the start and end months of the year. First pollen and spore peak were observed on 14 February and 23 April respectively. Maximum pollen concentration was observed in February–April, August–September. Spore concentration was high during March–May, August–October. Total 34 pollen families and 10 spore types were identified on morphological basis with Pinaceae (18%) found abundantly followed by Poaceae (11%) and Betulaceae (8%). Fall season prominent pollen families were Asteraceae and Cannabaceae. Some families with very low concentration were also identified categorized as “others”. Among spores, Alternaria and Aspergillus conidia were found maximum in April and September respectively. Statistical and qualitative investigation of dynamic interrelation between airborne pollen/spore and meteorological parameter explored the significant association with temperature and not-significant with rainfall and relative humidity. Wind speed was highly significant parameter for pollen loads but did not majorly affect the spore counts. It was observed from p-values obtained by single-factor ANOVA test. This study concluded that airborne pollen and spore loads influenced by variations in weather conditions and surrounding flora. Healthcare professionals can utilize findings of such researches for implementation of preventive measures to vulnerable population.

The novel spore-specific regulator SscA controls Aspergillus conidiogenesis.

Filamentous fungi produce myriads of asexual spores, which are the main reproductive particles that act as infectious or allergenic agents. Although the serial of asexual sporogenesis is coordinated by various genetic regulators, there remain uncharacterized transcription factors in Aspergillus. To understand the underlying mechanism of spore formation, integrity, and viability, we have performed comparative transcriptomic analyses on three Aspergillus species and found a spore-specific transcription factor, SscA. SscA has a major role in conidial formation, maturation and dormancy, and germination in Aspergillus nidulans. Functional studies indicate that SscA coordinates conidial wall integrity, amino acid production, and secondary metabolism in A. nidulans conidia. Furthermore, the roles of SscA are conserved in other Aspergillus species. Our findings that the SscA has broad functions in Aspergillus conidia will help to understand the conidiogenesis of Aspergillus species.

Effects of Aspergillus fumigatus Conidia on Apoptosis and Proliferation in an In Vitro Model of the Lung Microenvironment.

Background/Aim: Aspergillus is often detected in respiratory samples from patients with chronic respiratory diseases, including pulmonary fibrosis, suggesting that it can easily colonize the airways. To determine the role of Aspergillus colonization in pulmonary fibrosis, we cultured human lung epithelial A549 cells or murine embryo fibroblast NIH/3T3 cells with Aspergillus conidia in 3D floating culture representing the microenvironment. Materials and Methods: Cells were cultured in two-dimensional (2D) and three-dimensional floating (3DF) culture with heat-inactivated Aspergillus fumigatus (AF) 293 conidia at an effector-to-target cell ratio of 1:10 (early-phase model) and 1:100 (colonization model), and RNA-sequencing and Western blots (WB) were performed. Results: AF293 conidia reduced A549 cell growth in 2D and 3DF cultures and induced apoptosis in A549 spheroids in 3DF culture. RNA-sequencing revealed the increased expression of genes associated with interferon-mediated antiviral responses including MX dymamin-like GTPase 1 (MX1). Interestingly, the decreased expression of genes associated with the cell cycle was observed with a high concentration of AF293 conidia. WB revealed that epithelial-mesenchymal transition was not involved. Notably, AF293 conidia increased NIH/3T3 growth only in 3DF culture without inducing an apoptotic reaction. RNA-sequencing revealed the increased expression of genes associated with interferon signalling, including MX2; however, the decreased expression of genes associated with the cell cycle was not observed. Conclusions: AF affects both apoptosis of epithelial cells and the growth of fibroblasts. A deeper understanding of the detailed mechanisms underlying Aspergillus-mediated signaling pathway in epithelial cells and fibroblasts will help us to understand the lung microenvironment.

PS1128 FUNGI INFECTION VERSUS IBRUTINIB TREATMENT: ROLE OF NURSE‐LIKE CELLS DURING ASPERGILLUS FUMIGATUS INFECTION IN CHRONIC LYMPHOCYTIC LEUKEMIA PATIENTS

Background:Fungi are associated with a wide spectrum of diseases in humans ranging from acute pulmonary manifestations and cutaneous lesions in immunocompetent individuals to severe infections in immunocompromised patients. Infections by Aspergillus fumigatus from surrounding environment are common and the immunocompetent population are able to annihilate it. In tumor microenvironments, CLL cells escape immunosurveillance and “pull the strings” of the immune effector cells such as nurse like cells (NLC). NLC express BTK, a cytoplasmic tyrosine kinase belonging to Tec family kinases. The relevance of BTK expression in macrophages is related to regulation of macrophage lineage commitment. BTK is involved in the induction of M1 polarization, but it also functions as a negative regulator of M2‐polarizing signaling pathways mediating host immunity against fungal pathogens. Ibrutinib has significantly revoluzioned the landscape of the therapeutic strategy of CLL. Among the consistent clinical data, in the last years an increasing number of reports describing the occurrence of unexpected opportunistic fungal infections has been reported in patients treated with ibrutinib.Aims:We wondered to determine if ibrutinib may affect the immunological involvement of NLC during A.fumigatus response.Methods:NLC were generated in complete medium: cell surface markers and functional studies were performed after treatment with ibrutinib. Microarray‐based gene expression profiles of NLCs treated or not with ibrutinib were evaluated and data were confirmed by real time PCR and flow cytometry.Results:Ibrutinib reduced the level of phosphorylated BTK in NLC. Analysis of gene expression profiling showed that treatment with ibrutinib modified NLC gene expression profile. The supervised analysis identified 566 differentially expressed genes. The most represented down‐regulated genes were related to immune system process, inflammatory response, immune response, cytokine activity, implying the ability of ibrutinib to modify the expression of genes implicated in immune function of NLC. The down‐regulated profile included several genes belonging to TNF receptor family and IL‐1. The ability of NLC to induce a direct damage to the hyphae of A.fumigatus was significantly reduced by treatment with ibrutinib (P < 0.01). Moreover, ibrutinib reduced the ability of NLC to phagocyte zymosan particles (P < 0.05). We investigated the level of TNF‐α and IL‐1 production after treatment with ibrutinib either in presence or absence of zymogen or A.fumigatus stimulation. Of interest, ibrutinib decreased expression of TNF‐α and IL‐1 after stimulation with zymogen or Aspergillus conidia. We inspected the signaling pathways activated by A.fumigatus or zymosan in NLC. Stimulation with A.fumigatus activated phosphorylation of BTK, STAT1, IKK‐ß that were significantly inhibited by ibrutinib treatment. Moreover stimulation with zymosan induced phosphorylation of AKT and IKK‐ß in NLC that were reduced by ibrutinib. We extended our analysis on samples collected from CLL patients treated with ibrutinib. In a preliminary analysis on 9 samples, we found a significant reduction of TNF‐α secretion from CD14+ population in 5 patients after 3 months of treatment with ibrutinib compared to no treated samples.Summary/Conclusion:These data indicate that treatment with ibrutinib deeply modifies the macrophage population in CLL. These new insights may help to explain how ibrutinib allows invasive pulmonary aspergillosis by suppressing innate immune responses against A.fumigatus.

Genetic Polymorphisms Affecting IDO1 or IDO2 Activity Differently Associate With Aspergillosis in Humans.

Aspergillus is the causative agent of human diseases ranging from asthma to invasive infection. Genetic and environmental factors are crucial in regulating the interaction between the host and Aspergillus. The role played by the enzyme indoleamine 2,3-dioxygenase 1 (IDO1), which catalyzes the first and rate-limiting step of tryptophan catabolism along the kynurenine pathway, is increasingly being recognized, but whether and how genetic variation of IDO1 influences the risk of aspergillosis in susceptible patients is incompletely understood. In addition, whether the closely related protein IDO2 plays a similar role remains unexplored. In the present study, we performed genetic association studies in two different cohorts of susceptible patients [cystic fibrosis (CF) patients and recipients of hematopoietic stem cell transplantation (HSCT)], and identified IDO1 polymorphisms that associate with the risk of infection in both cohorts. By using human bronchial epithelial cells and PBMC from CF and HSCT patients, respectively, we could show that the IDO1 polymorphisms appeared to down-modulate IDO1 expression and function in response to IFNγ or Aspergillus conidia, and to associate with an increased inflammatory response. In contrast, IDO2 polymorphisms, including variants known to profoundly affect protein expression and function, were differently associated with the risk of aspergillosis in the two cohorts of patients as no association was found in CF patients as opposed to recipients of HSCT. By resorting to a murine model of bone marrow transplantation, we could show that the absence of IDO2 more severely affected fungal burden and lung pathology upon infection with Aspergillus as compared to IDO1, and this effect appeared to be linked to a deficit in the antifungal effector phagocytic activity. Thus, our study confirms and extends the role of IDO1 in the response to Aspergillus, and shed light on the possible involvement of IDO2 in specific clinical settings.

967. Inhibition of Host Neuraminidase Increases Susceptibility to Invasive Pulmonary Aspergillosis

BackgroundInfluenza-associated aspergillosis (IAA) is an emerging fungal infection with high mortality and morbidity and the pathogenesis of this disease is not well understood. Interestingly, the number of IAA case reports has increased since the widespread use of neuraminidase inhibitors, such as oseltamivir in 2009. We set out to determine whether oseltamivir could contribute to the pathogenesis of IAA by modulating host responses.MethodsFirst, peripheral blood mononuclear cells (PBMCs) and neutrophils from healthy donors were stimulated with neuraminidase (NA)-treated A. fumigatus or were pre-exposed to NA prior to stimulation with Aspergillus conidia. In addition, PBMCs and neutrophils were pretreated with oseltamivir carboxylate prior to stimulation. Cytokines were measured from supernatants after 24 hours of incubation at 37°C. C57BL/6 and BALB/c mice were treated with oseltamivir prior to intranasal challenge with A. fumigatus. Immunosuppression was induced by corticosteroid or cyclophosphamide.ResultsWe demonstrate that Aspergillus treated with NA induced an enhanced immune response. Moreover, PBMCs and neutrophils treated with NA produced increased cytokine responses. Blocking NA in vitro with oseltamivir reduced Aspergillus-induced cytokine responses. Next we investigated the effects of blocking neuraminidase activity with oseltamivir in vivo. Immunocompetent mice and mice treated with corticosteroids showed increased mortality, lung fungal burden, and decreased cytokine production when treated with oseltamivir. These effects were not observed in cyclophosphamide-treated mice, suggesting that the effects of NA activity in anti-Aspergillus host defense acts mainly via myeloid cells.ConclusionOur results provide evidence that host neuraminidase activity is important for protective anti-Aspergillus immune responses. Treatment with oseltamivir, thus blocking host NA activity, in a setting of corticosteroid use might therefore increase susceptibility to Aspergillus infection. These results warrant further study on the role of neuraminidase and the effects of oseltamivir on susceptibility to invasive pulmonary aspergillosis during active influenza infection.Disclosures All authors: No reported disclosures.

Aspergillus fumigatus conidia stimulate lung epithelial cells (TC-1 JHU-1) to produce IL-12, IFNγ, IL-13 and IL-17 cytokines: Modulatory effect of propolis extract

Aspergillus fumigatus conidia are the most prevalent indoors fungal allergens. The interaction between Aspergillus antigens and lung epithelial cells (LECs) result in innate immune functions. The association between Aspergillus conidia and allergic reactions, like allergic bronchopulmonary aspergillosis (ABPA) and asthma have been repeatedly reported. Since conventional therapies for allergy and asthma are limited, finding new promising treatments are inevitable. This study was designed to evaluate the effect of A. fumigatus conidia on IL-12, IFNγ, IL-13 and IL-17 release from mouse LECs and to investigate the effect of propolis on cytokines modulation. Cells were divided to two groups, one was exposed to 3×104 conidia of Aspergillus fumigatus and another group was treated by propolis (25μg/mL) as well as exposed to A. fumigatus conidia. Cytokines IL-13, IL-12, IFNγ and IL-17 were measured at times 0, 6 and 12hours after exposure using ELISA assay. The results indicated that A. fumigatus could increase the release of the cytokines with IL-13 and IL-17 being the most affected ones whilst treatment with propolis decreased the effects of A. fumigatus on IL-13 and IL-17 production. The results showed that propolis has down regulatory effects on Th2 cytokine, IL-13, and IL-17 production, whereas it caused a significant induction of IL-12, as an important Th1 cytokines by LECs. With respect to the obtained results, propolis extract might be contributed to decrease Th2 responses in allergic asthma phenomenon. However more investigations must be done in future to fully understand its efficacy.

Human MAITcells are rapidly activated by Aspergillus spp. in an APC-dependent manner.

Mucosal associated invariant Tcells (MAITcells) are innate-like Tcells (TC) which are known to be activated by several bacteria and viruses. However, activation of MAITcells by moulds, such as the opportunistic human pathogen Aspergillus, is not well described. Stimulation of human PBMC with A. fumigatus, A. flavus, or A. terreus conidia revealed that in contrast to conventional CD4+ and CD8+ TC, MAITcells responded already after 4 h of coincubation with upregulation of CD69. Furthermore, concurrent increase of CD107a expression and reduced intracellular expression of cytolytic proteins like perforin and granzyme indicated degranulation of intracellular vesicles. MAITcell activation only occurred in the presence of APC and was dependent on cell-cell contact as separation of TC and APC abrogated MAITcell activation. Furthermore, we observed that MAITcell activation by moulds requires presentation of riboflavin metabolites and depends on TCR engagement as antibody blocking of MR1, the antigen presenting molecule for MAITcells, prevented upregulation of CD69 and CD107a. In summary, we could demonstrate that MAITcells are activated by Aspergillus conidia in a TCR-dependent manner by APC. These findings reveal MAITcells as an interesting new target in antifungal defense.

Can Aspergillus fumigatus conidia cause false-positive results in the galactomannan enzyme immunoassay test?

Several factors can cause false-positive results in the galactomannan (GM) test; however, others remain unknown. Presently, the impact of airborne contamination by Aspergillus conidia during enzyme-linked immunosorbent assay (ELISA) remains uninvestigated. We studied 12 A. fumigatus isolates. Fungal conidia were serially diluted and tested for GM detection using the Platelia® Aspergillus enzyme immunoassay (EIA). The conidia concentration required for an EIA-positive result was 4.8 × 103 (median). This is the first study to evaluate the impact of environmental contamination on the Platelia® Aspergillus EIA assay. Only massive contamination can interfere with GM optical readings, suggesting that environmental contamination does not cause false-positive test results.

Epidemiology of Pathogenic Fungi from Private Hospital of Jabalpur, India

Fungi are ubiquitous in our environment, only a few people realize how intimately our lives are related to these fungi. Mycotic diseases of men are an emerging public health problem which receives growing alternate from the health authorities. The inter-human, mananimal and manenvironment relationship constitute the prime factors that explain the presence or absence of the infection. Special human activities and changes in human behavior are responsible for different susceptibilities in individual populations. Noscomial infections are transmitted in hospital through three main environmental routes-air, surface contact and water. This study reports the result of environmental surveillance of fungi in specific areas of Private Hospital of Jabalpur (M.P.). The air samples in the hospital yielded Aspergillus, Alternaria, Candida, Fusarium, Rhizopus, Penicillium, Tricophyton, and Microsporum. The dust samples were positive for Aspergillus, Alternaria and Fusarium. The sample of drinking water of the hospital no fungi was isolated. Key-wordsUbiquitous, Susceptibilities, Nosocomial infection, Surveillance -------------------------------------------------IJLSSR----------------------------------------------INTRODUCTION Pathogenic fungi are fungi that cause disease in human or other organism. Fungi are ubiquitous in our environment. Fungal infections of hospital origin are gaining importance in recent years due to their progressive increase into the high rates of mortality and morbility with which they are associated [1-2]. Hospital–acquired infection or nosocomial infections are one of leading cause of death in the world and typically affect patients whose immune systems are compromised. This paper reports the result of environmental surveillance of fungi in specific areas of Private hospital of Jabalpur (M.P.) Air, dust and drinking water samples were collected from hospital. Many of these infections are endogenous in nature, but others can be acquired by exogenous roots, through the hands of healthcare workers,contaminated infusion products and bioAccess this article online Quick Response Code: Website: www.ijlssr.com DOI: 10.21276/ijlssr.2016.2.6.12 materials and abiotic environmental sources [3]. Candida species remain a major cause of nosocomial infection. Candida albicans was the main agent for causing Fungemia and Funguria [4]. [1] Reported that many of fungal infections arise from an endogenous source. Outdoor air markedly influences the prevalence of fungal spore levels in indoor air and thus, is the major source of fungal infections in indoor environments especially in hospitalized individuals [5]. Mycotic diseases of man are an emerging public health problem which receives growing alternation from the health authorities. Aspergillus species are the common cause of hospital acquired fungal infection. Airborne spores probably also infect tissues exposed during surgery. Conidia of Aspergillus may gain entry, susceptible patient by contaminated hospital supplies [6-7]. [8] Isolated Aspergillus fumigates and A. Niger from the soil of various potted indoor plant kept in the room at the patient suffering from Aspergillosis. Aspergillums species were isolated in a multi centre hospital study from water mycoflora from the hospital environment [9]. In the hospital environment, the airborne micro biota is formed mainly by filamentous fungi, especially those belonging to the genera, Aspergillus, Cladosporium, Paecilomyces, Scopu Cariopsis [10]. Yeast has been found at the genera Candida, Rhodofforula, Uraptococeus and Trichosporon [11-13]. To identify the Research Article (Open access) Int. J. Life. Sci. Scienti. Res., VOL 2, ISSUE 6 http://ijlssr.com Copyright © 2015-2016 International Journal of Life-Sciences Scientific Research Page 730 source of fungal infection the environment of the patient, viz. air, water and dust of the hospitalized room were investigated for the presence of pathogen. The pathogen were isolated in culture and identified on the basis of culture, micro and macro morphology. MATERIALS AND METHODS Sampling Site: To explain the possible source of infection of deep mycoses, air, dust and water sample were screened from the environment of hospitalized patient were investigated. The air samples were collected from the General ward(G.W.), Private wards(P.W.), Deluxe room, Minor operation theater (MOT), Operation theater (OT), Intensive care unit (ICU). Dust sample were collected from the floor of passage of hospital and water sample was collected from the drinking water source of the hospital. At each location samples were taken at the time periods between 12:00 pm to 1:00pm which are visiting hours of the hospital. All the samples were taken during year 2015.

An Adenoviral Vector Encoding Full-Length Dectin-1 Promotes Aspergillus-Induced Innate Immune Response in Macrophages

The incidence of invasive pulmonary aspergillosis (IPA) has increased significantly over the last two decades. Alveolar macrophages (AMs) represent the first line of pulmonary host response to Aspergillus conidia. Recognition of conidia by AMs involves Dectin-1 (CLEC7A), which is a conserved structure to combine β-glucans. The deficiency of Dectin-1 results in impaired fungal killing and uncontrolled growth of Aspergillus fumigatus. Thus, we hypothesized that high expression of Dectin-1 would enhance the host recognition and fungal killing. We set out to develop an adenoviral vector encoding full-length Dectin-1 (Ad-Dectin-1-EGFP) and then transfect it to MH-S cells. Transfect cell model was verified by using real-time RT-PCR, Western blot, flow cytometric, and confocal microscopic assays. And also, the function of Dectin-1 was explored by measuring cytokine release and killing ability during the course of A. fumigatus infection. We constructed a recombinant adenovirus which could upregulate the expression of Dectin-1 and verified that Dectin-1 was expressed on cell membrane. The function of Dectin-1 was also demonstrated by its ability in promoting the production of cytokines and increasing the killing ability during the course of A. fumigatus infection. An adenoviral vector was successfully applied to the production of a recombinant adenovirus encoding full-length Dectin-1, and also, its function in Aspergillus-induced innate immune response was demonstrated.

Identification of Aspergillus fumigatus Surface Components That Mediate Interaction of Conidia and Hyphae With Human Platelets.

Platelets were recently identified as a part of innate immunity. They are activated by contact with Aspergillus fumigatus; putative consequences include antifungal defense but also thrombosis, excessive inflammation, and thrombocytopenia. We aimed to identify those fungal surface structures that mediate interaction with platelets. Human platelets were incubated with Aspergillus conidia and hyphae, isolated wall components, or fungal surface mutants. Interaction was visualized microscopically; activation was quantified by flow cytometry of specific markers. The capacity of A. fumigatus conidia to activate platelets is at least partly due to melanin, because this effect can be mimicked with "melanin ghosts"; a mutant lacking melanin showed reduced platelet stimulating potency. In contrast, conidial hydrophobin masks relevant structures, because an A. fumigatus mutant lacking the hydrophobin protein induced stronger platelet activation than wild-type conidia. A. fumigatus hyphae also contain surface structures that interact with platelets. Wall proteins, galactomannan, chitin, and β-glucan are not the relevant hyphal components; instead, the recently identified fungal polysaccharide galactosaminogalactan potently triggered platelet activation. Conidial melanin and hydrophobin as well as hyphal galactosaminogalactan represent important pathogenicity factors that modulate platelet activity and thus might influence immune responses, inflammation, and thrombosis in infected patients.

Establishment and application of loop-mediated isothermal amplification for detecting clinical isolates of Aspergillus spp

Objective To establish a method for detecting Aspergillus spp.by Loop-mediated isothermal amplification. Methods Aspergillus spp.specific primers were designed from the relative conservation region of the published sequence of 28S rRNA genes of A.fumigatus (GenBank accession number AY660917),A.terreus (GenBank accession number AF454183),A.flavus (GenBank accession number AF454158),and A.niger (GenBank accession number AF454169).Genomic DNA were extracted from Aspergillus standard strains,clinical control strains and clinical samples,and amplified by LAMP.The amplified results could be read with the naked eye by the coloring effect of fluorescent nucleotide dye without the DNA electrophoresis.Approximately 103 each Aspergillus conidia suspension was added to the serum from healthy volunteers,and detected these simulative clinical samples by LAMP assay. Results The LAMP and PCR assays obtained positive results for all four Aspergillus species and 8 simulative clinical samples (double samples for each Aspergillus species) including 103 conidia,but negative in the remaining 15 non-Aspergillus species,human total blood genomic DNA,30 clinical serum samples infected with non-Aspergillus and 10 healthy volunteers.The LAMP assay had a minimum detection of 0.05-0.5pg,by means of detect different levels of 500,50,5,0.5,0.05 pg template in each reaction tube. Conclusion The results confirm that LAMP is a simple,rapid,sensitive and specific method,and can be used for detection of Aspergillus strains in clinical and environmental specimens.（Chin J Lab Med,2014,37:140-143） Key words: Aspergillus; Nucleic acid amplification techniques; Sensitivity and specificity

Enhancing Angiogenesis in Invasive Aspergillosis: A Novel Therapeutic Approach

Invasive aspergillosis is one of the most devastating opportunistic infections in immunocompromised hosts, such as those with hematologic malignancies and those undergoing hematologic cell transplantation (HCT). Despite the recent availability of potent antifungal agents, mortality rates remain unacceptably high for invasive aspergillosis in these 2 patient groups, at 42% and 58%–72%, respectively [1–3]. One of the reasons for this lack of improvement in outcomes with current therapeutic regimens may lie in the pathogenesis of invasive aspergillosis. The major risk factors for invasive aspergillosis are neutropenia (ie, chemotherapy-induced neutropenia in patients with hematologic malignancies and HCT recipients in the early, preengraftment phase) and corticosteroid treatment (ie, for graft-versus-host disease during the postengraftment phase of HCT). The immunosuppression induced by these agents and the resulting pathogenesis of invasive aspergillosis may differ between these 2 immunosuppressive states. Aspergillus conidia are inhaled through the sinopulmonary tract and land in the pulmonary alveoli. In the immunocompetent host, the first lines of defense are the alveolar macrophage and the neutrophil. If the patient is immunosuppressed, either with cytotoxic agents (inducing neutropenia) or corticosteroids (impairing macrophage function), conidia survive and go on to germinate into hyphae. These hyphae then proceed to invade the alveolar endothelial cells and extend into the pulmonary arterioles, the final act of angioinvasion. Penetration of endothelial cells results in endothelial cell damage, proinflammatory cytokine release, activation of the coagulation cascade, and intravascular coagulation [4]. These events, in turn, lead to tissue hypoperfusion and tissue necrosis. Intravascular coagulation, tissue hypoperfusion, and necrosis lead to an ideal state for the survival and progression of Aspergillus hyphae, a sequestered infection in a privileged site without access to fungicidal macrophages or neutrophils or antifungal agents. There are differences, however, between the responses in neutropenic and corticosteroid-treated hosts. While the pulmonary lesions in neutropenic patients consist predominantly of angioinvasion and intravascular hemorrhage, the lesions in corticosteroid-treated patients consist mainly of neutrophilic and monocytic infiltrates and inflammatory necrosis [5]. Thus, although the result, tissue necrosis, is the same in both types of immunosuppression, the mechanisms, coagulative vs inflammatory necrosis, differ. Angiogenesis, the formation of new blood vessels from existing blood vessels, is a physiologic response to tissue inflammation and ischemia [6]. Thus, it is not surprising that Aspergillus infection induces angiogenesis. It was demonstrated that Aspergillus fumigatus hyphae stimulate the production of the proinflammatory cytokines tumor necrosis factor α (TNF-α) and interleukin 8 (IL-8) by endothelial cells [7] and that these are potent inducers of proangiogenic signaling pathways involving vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) [8]. A. fumigatus, however, produces many metabolites, including fumagillin and gliotoxin, that demonstrate antiangiogenic activity [9–12]. Thus, to determine the balance between proangiogenic and antiangiogenic factors in invasive aspergillosis, Ben-Ami et al [13] studied angiogenesis in a neutropenic model of cutaneous invasive aspergillosis. They noted that angiogenesis was suppressed by Aspergillus-infected mice, when compared to uninfected mice. The antiangiogenic effect was completely abolished Received and accepted 10 December 2012; electronically published 9 January 2013. Correspondence: James I. Ito, MD, Division of Infectious Diseases, City of Hope Comprehensive Cancer Center, 1500 E Duarte Rd, Duarte, CA 91010 ( jito@coh.org). The Journal of Infectious Diseases 2013;207:1031–3 © The Author 2013. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals. permissions@oup.com. DOI: 10.1093/infdis/jis944

Dectin-1 is inducible and plays a crucial role in Aspergillus-induced innate immune responses in human bronchial epithelial cells

Airway epithelial cells are the first cells to be challenged upon contact with the conidia of Aspergillus. In response, they express pattern-recognition receptors that play fundamental roles as sentinels and mediators of pulmonary innate immunity. The C-type lectin Dectin-1 is expressed predominantly on the surface of myeloid lineage cells. We examined the induction, regulation, and functions of Dectin-1 in pulmonary epithelial cells by challenging human bronchial epithelial (HBE) cells with A. fumigatus. Inflammatory, antimicrobial peptide genes and reactive oxygen species (ROS) were quantified, with and without knockdown of Dectin-1. We found that A. fumigatus induced the expression of Dectin-1 mRNA and protein in HBE cells in a toll-like receptor (TLR) 2-dependent manner. In addition, A. fumigatus-mediated generation of ROS was dependent on the upregulation of Dectin-1. Moreover, A. fumigatus actively induced the expression of TNFα, GM-CSF, IL8, HBD2, and HBD9. Knockdown of Dectin-1 inhibited TNFα, IL8, HBD2, and HBD9 expression. Hence, Dectin-1 was required for the upregulation of pro-inflammatory cytokines and antimicrobial peptides. Finally, knockdown of TLR2 significantly inhibited Dectin-1 upregulation. Our results demonstrate the novel induction of Dectin-1 in human bronchial epithelial cells and its critical role in the innate immune response against A. fumigatus in non-phagocytic cells.

Phagocytosis of melanized Aspergillus conidia by macrophages exerts cytoprotective effects by sustained PI3K/Akt signalling

Host cell death is a critical component of innate immunity and often determines the progression and outcome of infections. The opportunistic human pathogen Aspergillus fumigatus can manipulate the immune system either by inducing or by inhibiting host cell apoptosis dependent on its distinct morphological form. Here, we show that conidia of Aspergillus ssp. inhibit apoptosis of macrophages induced via the intrinsic (staurosporine) and extrinsic (Fas ligand) pathway. Hence, mitochondrial cytochrome c release and caspase activation were prevented. We further found that the anti-apoptotic effect depends on both host cell de novo protein synthesis and phagocytosis of conidia by macrophages. Moreover, sustained PI3K/Akt signalling in infected cells is an important determinant to resist apoptosis. We demonstrate that pigmentless pksP mutant conidia of A. fumigatus failed to trigger protection against apoptosis and provide evidence that the sustained survival of infected macrophages depends on the presence of the grey-green conidial pigment consisting of dihydroxynaphthalene-melanin. In conclusion, we revealed a novel potential function of melanin in the pathogenesis of A. fumigatus. For the first time, we show that melanin itself is a crucial component to inhibit macrophage apoptosis which may contribute to dissemination of the fungus within the host.

Guidelines for the prevention of invasive mould diseases caused by filamentous fungi by the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC)

Invasive fungal infections (IFIs) caused by filamentous fungi still have high rates of mortality, associated with difficulties in early detection of the infection and therapeutic limitations. Consequently, a useful approach is to prevent patients at risk of fungal infection from coming into contact with conidia of Aspergillus and other mould species. This document describes the recommendations for preventing IFI caused by filamentous fungi worked out by Spanish experts from different medical and professional fields. The article reviews the incidence of IFI in different risk populations, and questions related to environmental measures for prevention, control of hospital infections, additional procedures for prevention, prevention of IFI outside of hospital facilities and antifungal prophylaxis are also analysed.

Invasive aspergillosis promotes tumor growth and severity in a tumor-bearing mouse model

Invasive aspergillosis increases in chronic immunosuppressive diseases such as cancer. There is little information about the mechanisms by which Aspergillus infection affects the immune regulation and microenvironment of cancer cells. Hence, this study was aimed at investigating the effect of invasive aspergillosis on immunosurveillance, metastasis, and prognosis of cancer in tumor-bearing mice. After implantation of mouse mammary tumor in BALB/c mice, they were infected with Aspergillus conidia intravenously. For comparison, groups of mice were experimentally infected with Aspergillus conidia or implanted with tumor cells separately. Seven days after Aspergillus infection, the serum levels of tissue inhibitor of metalloproteinase-1 (TIMP-1) were measured by ELISA, and subsequently regulatory T lymphocytes were analyzed by flow cytometry. The survival of animals and mean tumor size were then determined. Our results indicated that tumor sizes in mice increased significantly after infection with Aspergillus conidia. Moreover, invasive aspergillosis enhanced the population of regulatory lymphocytes and level of TIMP-1. This study supports the idea that massive Aspergillus infection could stimulate tumor growth and increases the possibility of a bad prognosis. As a result, treatment of Aspergillus infection could be considered an important issue for efficient cancer therapy.

Recomendaciones sobre la prevención de la infección fúngica invasora por hongos filamentosos de la Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica (SEIMC)

Invasive fungal infections (IFI) due to filamentous fungi still have high rates of mortality associated with the difficulties of early detection of the infection and their therapeutic limitations. Consequently, a useful approach is to prevent patients at risk of fungal infection from getting in contact with conidia of Aspergillus and other mould species. This document describes the recommendations to prevent IFI due to filamentous fungi, prepared by Spanish experts from different medical and professional fields. The paper reviews the incidence of the IFI in different risk populations and the questions related to environmental measures of prevention, control of hospital infections, additional procedures for prevention, prevention of IFI outside hospitals, as well as antifungal prophylaxis.

Adsorption of zearalenone by Aspergillus japonicus conidia: new trends for biological decontamination in animal feed

Zearalenone (ZEA) is an oestrogenic mycotoxin produced by Fusarium spp. on a wide variety of grains. The presence of ZEA impairs farm animal health. In this study, the ability to remove ZEA by conidia of Aspergilli was evaluated in vitro. This mycotoxin was successfully eliminated in vitro by living and heat-treated conidia just after conidial inoculation, especially by Aspergillus japonicus Mu541 (IMI389204) conidia. Consequently, components involved in adsorption are not affected by heat-treatment. The influence of pH on ZEA removal was also determined. Results have shown that ZEA removal was 53% at pH 2 while 2% removal was observed at pH 11. Then, the adsorption capacity was evaluated in vitro in porcine gastrointestinal tract conditions. We observed that there was better adsorption in acidic stomach conditions. Finally, the phenomenon has been modelled using Hill's equation. This model was very suitable and confirmed better adsorption at acidic pH. Aspergilli section Nigri conidia were able to adsorb ZEA instantaneously especially in acidic conditions as in the stomach. The use of heat-treated conidia could be a very interesting means of decreasing ZEA levels in animal feed. It must now be assessed directly on naturally contaminated feed and on animals.