Aspergillus fumigatus tryptophan metabolic route differently affects host immunity

Indoleamine 2,3-dioxygenases (IDOs) degrade l-tryptophan to kynurenines and drive the de novo synthesis of nicotinamide adenine dinucleotide. Unsurprisingly, various invertebrates, vertebrates, and even fungi produce IDO. In mammals, IDO1 also serves as a homeostatic regulator, modulating immune response to infection via local tryptophan deprivation, active catabolite production, and non-enzymatic cell signaling. Whether fungal Idos have pleiotropic functions that impact on host-fungal physiology is unclear. Here, we show that Aspergillus fumigatus possesses three ido genes that are expressed under conditions of hypoxia or tryptophan abundance. Loss of these genes results in increased fungal pathogenicity and inflammation in a mouse model of aspergillosis, driven by an alternative tryptophan degradation pathway to indole derivatives and the host aryl hydrocarbon receptor. Fungal tryptophan metabolic pathways thus cooperate with the host xenobiotic response to shape host-microbe interactions in local tissue microenvironments.

Invasive fungal disease misdiagnosed as tumour in association with orbital apex syndrome

Invasive sino-orbital aspergillosis is a rare cause of orbital apex syndrome (OAS) in immunocompetent patients and often misdiagnosed as tumour because of its aggressive nature and invasive patterns. We report a 23-year-old immunocompetent man presenting with painful progressive loss of vision, ophthalmoplegia and proptosis of the right eye suggestive of OAS. MRI with gadolinium contrast showed an enhancing heterogeneous mass filling the paranasal sinuses, extraconal space and extending up to the right orbital apex. A functional endoscopic biopsy reported as invasive sino-orbital aspergillosis. He was started on intravenous voriconazole and maximal surgical debridement was done. He gradually regained his vision to 20/30 in the right eye. A review of literature reported several such cases which were managed medically or surgically but with poor visual recovery. This case highlights the need for awareness among clinicians for early diagnosis and treatment to prevent vision loss and better survival.

Galectin-3 enhances neutrophil motility and extravasation into the airways during Aspergillus fumigatus infection

Aspergillus fumigatus is an opportunistic mold that infects patients who are immunocompromised or have chronic lung disease, causing significant morbidity and mortality in these populations. While the factors governing the host response to A. fumigatus remain poorly defined, neutrophil recruitment to the site of infection is critical to clear the fungus. Galectin-3 is a mammalian β-galactose-binding lectin with both antimicrobial and immunomodulatory activities, however the role of galectin-3 in the defense against molds has not been studied. Here we show that galectin-3 expression is markedly up-regulated in mice and humans with pulmonary aspergillosis. Galectin-3 deficient mice displayed increased fungal burden and higher mortality during pulmonary infection. In contrast to previous reports with pathogenic yeast, galectin-3 exhibited no antifungal activity against A. fumigatus in vitro. Galectin-3 deficient mice exhibited fewer neutrophils in their airways during infection, despite normal numbers of total lung neutrophils. Intravital imaging studies confirmed that galectin-3 was required for normal neutrophil migration to the airspaces during fungal infection. Adoptive transfer experiments demonstrated that stromal rather than neutrophil-intrinsic galectin-3 was necessary for normal neutrophil entry into the airspaces. Live cell imaging studies revealed that extracellular galectin-3 directly increases neutrophil motility. Taken together, these data demonstrate that extracellular galectin-3 facilitates recruitment of neutrophils to the site of A. fumigatus infection, and reveals a novel role for galectin-3 in host defense against fungal infections.

The environmental mold Aspergillus fumigatus commonly causes lung infections in people with impaired immunity or those suffering from a chronic lung disease. While neutrophils are a key cell type necessary for the eradication of this infection, the precise mechanism of their recruitment to the site of infection remains incompletely understood. Here we show that the secreted mammalian protein galectin-3 plays an important role in helping neutrophils reaching the fungus within the airways. We found that both mice and humans produce galectin-3 when infected with A. fumigatus, and mice lacking galectin-3 were more susceptible to infection than normal mice. Galectin-3-deficient mice had impaired neutrophil recruitment to the site of infection. In the absence of galectin-3, neutrophils exhibited reduced motility in mouse lungs and in tissue culture. Our study offers insights into the mechanisms underlying the recruitment of neutrophils to the airways during A. fumigatus infection and reveals a new role for galectin-3 in increasing neutrophil motility.

Labeled quantitative mass spectrometry to study the host response during aspergillosis in the common bottlenose dolphin (Tursiops truncatus)

Aspergillosis is a fungal infection caused by Aspergillus molds that can affect both humans and animals. Despite advances in diagnostics and therapy, medical management of this disease remains difficult. Expansion of the basic knowledge regarding its pathophysiology in animals is critical to aid in the identification of new biomarkers of infection for diagnosis and therapeutic targets. For such a purpose, proteomics can be used by addressing protein changes during various disease processes. In the present study, a mass spectrometry analysis based on isobaric tagging for relative and absolute quantitation (iTRAQ^®) was applied for direct identification and relative quantitation of proteins in blood collected from 32 Aspergillus-diseased common bottlenose dolphins (Tursiops truncatus, 32 samples) in comparison with blood from 55 other dolphins (55 samples from 41 clinically-normal controls and from 14 cetaceans with miscellaneous non-Aspergillus inflammation diseases) and ten convalescent dolphins (28 samples). Sixty-six and 40 proteins were found to be ≥2.0-fold over- and underrepresented versus miscellaneous non-Aspergillus inflammatory dolphins, respectively, and most were confirmed vs. clinically-normal controls and convalescents. Many proteins which play a role in the adaptive immune response were identified, including MHC proteins and others involved in catalytic activity like the NADPH-ubiquinone oxido-reductases. Overall, iTRAQ^® appears to be a convenient proteomic tool greatly suited for exploratory ex vivo studies focusing on pathophysiology. This technique should be considered as a preliminary step before validation of new diagnostic markers.

Fungal osteomyelitis in a patient with chronic granulomatous disease: Case report and review of the literature

Chronic granulomatous disease (CGD) is the most common of the primary immunodeficiency in children. It is caused by single gene defect resulting in dysfunctional nicotinamide adenine dineucleotide phosphate (NADPH) oxidase complex causing recurrent bacterial and fungal infections. Here we present the case of a 9 year old boy who was a known case of CGD since three years of age. He presented with recent history of fever, left sided pain in the scapular region and difficulty in breathing. Chest imaging revealed developing left upper lobe consolidation and erosion of the 3rd posterior rib. The child underwent video assisted thoracoscopic surgery (VATS) and biopsy of the lesion. Histopathology revealed fungal hyphae which were confirmed to be Aspergillus nidulans on staining. He was successfully treated with voriconazole therapy. We will also review the literature on fungal osteomyelitis in CGD patients.

[NADPH oxidase-induced macrophage autophagy mediated by reactive oxygen species in Aspergillus fumigatus infection]

OBJECTIVE

To investigate whether or not NADPH oxidase (NOX) participates in Aspergillus fumigatus induced macrophage autophagy in RAW264.7 cells and explore the possible mechanism.

METHODS

RAW264.7 cells in the exponential growth phase were randomized into three groups: Aspergillus fumigatus conidia (MOI 5:1) treated group, Aspergillus fumigatus conidia plus NOX inhibitor diphenyleneiodonium chloride (DPI) treated group; negative control group (untreated). The levels of intracellular reactive oxygen species (ROS) were measured with dichiorodihydrofluorescein diacetate (DCFH-DA) staining by fluorescence microscope. The expression of microtubule-associated protein light chain-3 (LC3) protein in RAW264.7 cells was detected by Western blotting. Then the expression and positioning of LC-3 were observed by immunofluorescence staining.

RESULTS

After stimulated with conidia of Aspergillus fumigatus, RAW264.7 cells showed significant increases of ROS and LC3BII. Interestingly, LC3 was recruited to phagosomes which contained Aspergillus fumigatus conidia. After the NOX inhibitor DPI blocked the ROS production, the expressions of ROS and LC3BII had no significant increases as compared with the negative control group, and the distribution of LC3 was diffuse in cytoplasm.

CONCLUSION

NOX induces macrophage autophagy by producing ROS in Aspergillus fumigatus infection.

An unusual case of invasive Aspergillus ulcerative tracheobronchitis without involvement of lung parenchyma in a post-renal transplant patient

We present the case of a 54-year-old male, who presented with respiratory complaints four months after he underwent renal transplantation. Bronchoscopy showed ulcerated mucosa of the left main bronchus and computed tomography (CT) of the thorax showed foci of air within the bronchial wall. A biopsy from the lesion showed septate fungal hyphae, dichotomously branching at acute angles. A locally invasive Aspergillus ulcerative tracheobronchitis with no parenchymal involvement is an important cause of tracheobronchitis in post-renal transplant patients. An early diagnosis and institution of appropriate treatment can improve the outcome. A combination treatment of caspofungin and voriconazole can be considered if patient is not responding to voriconazole alone.

[The aspergillus laryngotracheobronchitis. A case report and literature review]

The patient presented with dry cough, lending, fever and progressive dyspnea for two weeks. The patient had a prior respiratory infection history and the symptoms were not obvious, Early X-ray showed lung infection. Under the fibrolaryngoscope, the lingual surfaces of the epiglottis, epiglottic vallecula, and bilateral vocal cords were covered by yellow pseudomembrane. The motion of vocal cords was normal with poor glottic closure, and no ulcer was noted. Endotracheal mucosa was swelling and congested with an uneven surface, and purulent discharge and pseudomembrane was formed. Pathological examination revealed Aspergillus. The disease was diagnosed as Aspergillus laryngotracheobronchitis.

Lymphoid proliferations of indeterminate malignant potential arising in adults with common variable immunodeficiency disorders: unusual case studies and immunohistological review in the light of possible causative events

Patients with common variable immunodeficiency disorders (CVIDs) who developed B cell lymphoproliferation of indeterminate malignant potential are described in order to raise a discussion of the relationship between infection and lymphoproliferation in infection prone patients. Those with CVID are at risk of developing either polyclonal or monoclonal lymphoproliferation in part due to the dysregulation of their adaptive immune systems. The aetiologies of the lymphoproliferations are unknown but intriguing; the relevance of infection being particularly problematic. The patients described here demonstrate variability in preceding infection, age at presentation, response to antibiotics and other types of therapy as well as outcome. The question of treatment is also controversial; issues include whether antibiotics or chemotherapy are the first line of therapy in all patients and whether transformation to aggressive B cell malignancy is inevitable or depends on other factors and if so, the length of time for such progression.

Calcineurin target CrzA regulates conidial germination, hyphal growth, and pathogenesis of Aspergillus fumigatus

The calcineurin pathway is a critical signal transduction pathway in fungi that mediates growth, morphology, stress responses, and pathogenicity. The importance of the calcineurin pathway in fungal physiology creates an opportunity for the development of new antifungal therapies that target this critical signaling pathway. In this study, we examined the role of the zinc finger transcription factor Crz1 homolog (CrzA) in the physiology and pathogenicity of the opportunistic human fungal pathogen Aspergillus fumigatus. Genetic replacement of the crzA locus in A. fumigatus resulted in a strain with significant defects in conidial germination, polarized hyphal growth, cell wall structure, and asexual development that are similar to but with differences from defects seen in the A. fumigatus DeltacnaA (calcineurin A) strain. Like the DeltacnaA strain, the DeltacrzA strain was incapable of causing disease in an experimental persistently neutropenic inhalational murine model of invasive pulmonary aspergillosis. Our results suggest that CrzA is an important downstream effector of calcineurin that controls morphology in A. fumigatus, but additional downstream effectors that mediate calcineurin signal transduction are likely present in this opportunistic fungal pathogen. In addition, the importance of CrzA to the production of disease is critical, and thus CrzA is an attractive fungus-specific antifungal target for the treatment of invasive aspergillosis.

Outbreak of severe disseminated aspergillosis in a flock of ostrich (Struthio camelus)

This study was undertaken to describe clinical, mycological and histopathological findings in black neck ostriches affected with severe aspergillosis in a flock including 80 birds, near Tehran, Iran. The signs included anorexia, depression, notable weight loss, diarrhoea, severe respiratory distress and death. Grossly, the lungs showed numerous white to yellow caseous nodules and the walls of the thoracic and abdominal air sacs were thickened with inflammatory exudates containing cellular debris, necrotic masses and green mold colonies. Multiple nodules were observed in the liver, spleen and gastrointestinal tract as well. Histopathologically, there were conidial heads and fungal hyphae in the air sacs and multifocal necrotic and granulomatous lesions with septated and dichotomously branched hyphae in various tissues, which were stained with haematoxylin and eosin and Grocott's methenamine silver nitrate. Aspergillus fumigatus was isolated in various tissues taken from affected ostriches.

Primary aspergillosis of the cheek. A diagnostic dilemma

Primary cutaneous and subcutaneous aspergillosis is a rare entity and usually occurs secondary to systemic or disseminated aspergillosis. We describe a unique case of primary aspergillosis of the cheek in a 45-year-old male without any evidence of disseminated aspergillosis and recognizable trauma or surgical procedure in the area of cheek.

Distinct roles for intra- and extracellular siderophores during Aspergillus fumigatus infection

Siderophore biosynthesis by the highly lethal mould Aspergillus fumigatus is essential for virulence, but non-existent in humans, presenting a rare opportunity to strategize therapeutically against this pathogen. We have previously demonstrated that A. fumigatus excretes fusarinine C and triacetylfusarinine C to capture extracellular iron, and uses ferricrocin for hyphal iron storage. Here, we delineate pathways of intra- and extracellular siderophore biosynthesis and show that A. fumigatus synthesizes a developmentally regulated fourth siderophore, termed hydroxyferricrocin, employed for conidial iron storage. By inactivation of the nonribosomal peptide synthetase SidC, we demonstrate that the intracellular siderophores are required for germ tube formation, asexual sporulation, resistance to oxidative stress, catalase A activity, and virulence. Restoration of the conidial hydroxyferricrocin content partially rescues the virulence of the apathogenic siderophore null mutant Delta sidA, demonstrating an important role for the conidial siderophore during initiation of infection. Abrogation of extracellular siderophore biosynthesis following inactivation of the acyl transferase SidF or the nonribosomal peptide synthetase SidD leads to complete dependence upon reductive iron assimilation for growth under iron-limiting conditions, partial sensitivity to oxidative stress, and significantly reduced virulence, despite normal germ tube formation. Our findings reveal distinct cellular and disease-related roles for intra- and extracellular siderophores during mammalian Aspergillus infection.

Economic evaluation of voriconazole versus caspofungin for the treatment of invasive aspergillosis in Spain

BACKGROUND AND OBJECTIVE

Invasive fungal infections are becoming increasingly prevalent and are more frequently the aetiological agents responsible for nosocomial infections. Since mid-2002, two new antifungal drugs - voriconazole, a third-generation azole, and caspofungin, a member of a new class of drugs called echinocandins - have been marketed in Spain. Both drugs have proven [corrected] efficacy in the treatment of aspergillosis, are better tolerated than amphotericin B and are cheaper [corrected] than liposomal amphotericin B. The objective of this study was to conduct an economic evaluation of voriconazole versus caspofungin for the treatment of invasive aspergillosis in Spain.

METHODS

This was a cost-minimisation analysis (2006 costs) from the hospital perspective. Duration of treatment and bodyweight of patients were obtained from the Fungcost study and the incidence of adverse events was obtained from different published sources. Only direct costs were considered. Mean expected cost and incremental cost were calculated, and univariate and bivariate (bodyweight/treatment duration) sensitivity analyses were conducted.

RESULTS

The mean expected cost per episode was 6041.93 euro (intravenous treatment acquisition cost 5524.75 euro) for voriconazole and 7174.05 euro (intravenous treatment acquisition cost 6672.80 euro) for caspofungin in invasive aspergillosis; the incremental cost was 1132.18 euro. Results were robust for any treatment duration and sensitive to bodyweights <103.42 kg.

CONCLUSION

Voriconazole is a more cost-effective option than caspofungin in invasive aspergillosis in patients with a bodyweight <103.42 kg.

Exploring the non-viral infectious causes of cancer

This article discusses the contribution made by non-viral infections to the global burden of cancer and describes the bacterial, protozoan and fungal organisms that are believed to cause cancer, either directly or indirectly.

Gliotoxin production by clinical and environmental Aspergillus fumigatus strains

The mycotoxin gliotoxin is produced by fungi of the genus Aspergillus, including the important human pathogen Aspergillus fumigatus. Gliotoxin exerts a broad spectrum of immunosuppressive effects in vitro and is detectable in the sera of patients suffering from invasive aspergillosis. In order to correlate the pathogenic potential of A. fumigatus with the ability to produce gliotoxin and to investigate the taxonomic distribution of gliotoxin-producing Aspergillus strains among clinical isolates, a total of 158 Aspergillus isolates comprising four different species (A. fumigatus, n=100; A. terreus, n=27; A. niger, n=16; A. flavus, n=15) were collected from different medical centers (some originating from probable cases of aspergillosis) and from environmental samples in Germany and Austria. Remarkably, gliotoxin was detected in most culture filtrates of A. fumigatus of both clinical (98%) and environmental (96%) origin. The toxin was also detected, with decreasing frequency, in culture filtrates of A. niger (56%), A. terreus (37%), and A. flavus (13%). The highest gliotoxin concentrations were detected in A. fumigatus strains of clinical (max. 21.35 microg/ml, mean 5.75 microg/ml) and environmental (max. 26.25 microg/ml, mean 5.27 microg/ml) origin. Gliotoxin productivity of other Aspergillus species was significantly lower. Culture supernatants of A. fumigatus strains lacking gliotoxin production showed a significantly lower cytotoxicity on macrophage-like cells and T-cells in vitro. In contrast, lack of gliotoxin production in the other Aspergillus species tested had no significant influence on the cytotoxic effect of culture supernatant on these immune cells.

Favorable Acute and Long-Term Outcomes after the Resection of Pulmonary Aspergillomas

OBJECTIVE

This retrospective study was designed to examine the acute and long-term outcomes after surgical treatment of patients with pulmonary aspergillomas.

PATIENTS AND METHODS

From 1992 to 2006, 24 patients (21 men, mean age 58.4 years) with pulmonary aspergillomas underwent pulmonary resection. Operative indications were massive or repetitive hemoptysis in 6 patients, medically unmanageable localized infection in 14 patients, and undetermined mass in 4 patients. Eighteen patients (75.0 %) had background pulmonary diseases and four patients (16.7 %) were mildly immunocompromised. Eight patients had simple aspergillomas, while sixteen patients had complex aspergillomas. Two patients with pleural empyema had their pleural spaces sterilized before pulmonary resections. Fungus balls and pulmonary cavities along with the surrounding lung were removed in all patients.

RESULTS

Surgical procedures consisted of 13 lobectomies, 5 pneumonectomies including one completion pneumonectomy, 2 segmentectomies and 4 wedge resections. Postoperative complication occurred in 10 patients (41.6 %) and one patient died from aortic bleeding due to postoperative empyema. Other major complications were prolonged air leaks, bleeding, and chylothorax. In the follow-up period, all but one patient were free from aspergillosis. Hemoptysis was not seen in any patient. Overall survival rates at 2, 5, and 10 years were 86.6 %, 79.4 % and 79.4 %, respectively. Disease-free survival rates from aspergillosis were 86.6 %, 72.6 % and 72.6 % at 2, 5, and 10 years, respectively.

CONCLUSION

Pulmonary resection for aspergilloma showed favorable acute and long-term outcomes when surgical treatment was applied in selected patients.

Torsades de pointes associated with voriconazole use

We describe 2 patients who developed prolonged QTc interval on electrocardiogram while being treated with voriconazole. The first patient had undergone induction chemotherapy for acute myelogenous leukemia, and her course had been complicated by invasive aspergillosis and an acute cardiomyopathy. She developed torsades de pointes 3 weeks after starting voriconazole therapy. She was re-challenged with voriconazole without recurrent QTc prolongation or cardiac dysfunction. The second patient had a significantly prolonged QTc interval while on voriconazole therapy. We recommend careful monitoring for QTc prolongation and arrhythmia in patients who are receiving voriconazole, particularly those who have significant electrolyte disturbances, are on concomitant QT prolonging medications, have heart failure such as from a dilated cardiomyopathy, or have recently received anthracycline-based chemotherapy. The potential for synergistic cardiotoxicity must be carefully considered.

Invasive aspergillosis following hematopoietic cell transplantation: outcomes and prognostic factors associated with mortality

BACKGROUND

Invasive aspergillosis (IA) is a leading cause of infection-related mortality following hematopoietic cell transplantation (HCT). The aim of this study was to determine the probability of survival and prognostic factors associated with outcomes over a long period of time.

METHODS

Cases of proven and probable IA diagnosed in HCT recipients at the Fred Hutchinson Cancer Research Center from 1 January 1990 through 31 December 2004 were included. Patient data were collected from a prospectively maintained database and by retrospective clinical chart review. Survival was estimated using Kaplan-Meier curves, and Cox regression models were used for multivariable analyses.

RESULTS

Four hundred five cases were identified. The probability of survival at 90 days after diagnosis was higher for patients identified as having IA between 2002 and 2004 than for patients whose IA was diagnosed in preceding years (45% vs. 22%; P<.001). Risk factors independently associated with all-cause mortality include impairment in pulmonary function before HCT, receipt of human leukocyte antigen-mismatched stem cells, neutropenia, elevated bilirubin and creatinine levels, receipt of corticosteroids at > or =2 mg/kg per day, disseminated and proven IA, and IA occurring >40 days after HCT. Factors associated with a decreased risk of all-cause mortality included receipt of nonmyeloablative conditioning and peripheral blood stem cells. In a subanalysis of attributable mortality restricted to patients receiving antifungal therapy, receipt of voriconazole was independently associated with protection from IA-related death.

CONCLUSIONS

There has been a significant decrease in mortality in patients with a diagnosis of IA following HCT in recent years, coinciding with multiple changes in transplantation practices, including use of nonmyeloablative conditioning regimens, receipt of peripheral blood stem cells, more prompt diagnosis of IA, and use of voriconazole.

Fungus and chronic rhinosinusitis: from bench to clinical understanding

Although fungus-related sinusitis has been described for at least 2 centuries, a more detailed pathologic description of the problem as it relates to eosinophilic disease was not detailed until 1983, when "allergic fungal sinusitis" was described histopathologically. Until then, most fungal sinus disease was perceived to occur in immunosuppressed diabetic patients with invasive fungus. It is now acknowledged that depending upon the immune status of the host, fungus-related sinus disease can take several forms. Interest in this subject matter was intensified in 1999, when it was suggested that fungi might be an important cause of most cases of chronic rhinosinusitis. This hypothesis remains controversial, and there is mounting evidence to support the multifactorial nature of chronic rhinosinusitis, which may include fungus. In fact, etiologic factors for all forms of fungus-related sinus disease are still poorly understood. The prevalence of the disease and the dominant fungal pathogen appear to vary in different geographic regions and probably are related to individual host conditions. Immunoglobulin E-mediated allergic reactions to mold appear to be associated with disease in some patients, but not in all. Although antifungal therapy is known to be lifesaving for invasive disease, its role in extramucosal disease is less well defined. Preliminary trials suggest that some systemic and topical antifungal agents are of clinical benefit in extramucosal disease. Since sinus fungi are rarely invasive in immunocompetent individuals, it is not clear whether the effects of the antifungal treatments are a result of the antifungal action itself, or due to additional properties these drugs possess. This review summarizes the available data and presents some of our clinical and experimental findings as to the role of fungus in chronic rhinosinusitis.

The mitochondrial protein Bak is pivotal for gliotoxin-induced apoptosis and a critical host factor of Aspergillus fumigatus virulence in mice

Aspergillus fumigatus infections cause high levels of morbidity and mortality in immunocompromised patients. Gliotoxin (GT), a secondary metabolite, is cytotoxic for mammalian cells, but the molecular basis and biological relevance of this toxicity remain speculative. We show that GT induces apoptotic cell death by activating the proapoptotic Bcl-2 family member Bak, but not Bax, to elicit the generation of reactive oxygen species, the mitochondrial release of apoptogenic factors, and caspase-3 activation. Activation of Bak by GT is direct, as GT triggers in vitro a dose-dependent release of cytochrome c from purified mitochondria isolated from wild-type and Bax- but not Bak-deficient cells. Resistance to A. fumigatus of mice lacking Bak compared to wild-type mice demonstrates the in vivo relevance of this GT-induced apoptotic pathway involving Bak and suggests a correlation between GT production and virulence. The elucidation of the molecular basis opens new strategies for the development of therapeutic regimens to combat A. fumigatus and related fungal infections.

Invasive aspergillosis in the recipients of liver retransplantation

Retransplantation is a major risk factor for invasive aspergillosis in liver transplant recipients. However, the risk for invasive aspergillosis with time elapsed since retransplantation, clinical characteristics, and outcome of patients who develop this infection after retransplantation of the liver has not been defined. Patients comprised 17 liver retransplant recipients with invasive aspergillosis between 1990 and 2004. Retransplantation was considered early if it was performed within 30 days and late if performed after 30 days of the first or primary transplant. Retransplant recipients comprised 25% of all cases of invasive aspergillosis after liver transplantation. Fifty-three percent of the Aspergillus infections occurred within 30 days, and 76% within 90 days of retransplantation. In all, 53% (9/17) of the patients were late retransplant recipients. Late compared to early retransplant recipients with invasive aspergillosis were more likely to have central nervous system involvement with invasive aspergillosis (56% vs. 0%, P = 0.03). Mortality rate was 100% for late and 63% for early retransplant recipients with Aspergillus infections. In conclusion, time-varying risk for invasive aspergillosis after retransplantation has implications relevant for guiding antifungal prophylaxis. Given a greater risk for disseminated infection and poor outcome in late retransplant recipients with aspergillosis, potent and aggressive antifungal therapy should be considered upfront in these patients.

Disseminated aspergillosis in two dogs in Israel

Aspergillus terreus, normally a soil or plant saprophyte, causes disseminated systemic infection, involving primarily the skeletal and the cardiopulmonary system in humans and dogs.(1, 2) We describe two cases of German shepherd dogs that were referred to Koret School of Veterinary Medicine Teaching Hospital with a history of anorexia and weakness. Case 1 suffered from neurological deficits, paraparesis and lumbar pain whereas case 2 suffered from unilateral uveitis and exophthalmus. Both dogs were treated symptomatically, but deteriorated progressively despite therapy and were therefore euthanised. Necropsy revealed disseminated aspergillosis, and numerous organs had multiple, miliary, white-yellow foci. Microscopically, these were identified as granulomas, containing fungal hyphae. Affected tissue included brain, heart, kidneys, spleen, lymph nodes and bones (case 2). Aspergillus terreus was isolated from different organs and from urine culture. We suggest that disseminated aspergillosis should be considered as a differential diagnosis in German shepherd dogs presenting with ocular disease, neurological deficits, spinal column pain, urinary system disorders, and radiographic evidence of skeletal and/or respiratory pathology.

Systemic fungal infections caused by Aspergillus species: epidemiology, infection process and virulence determinants

Infections with mould pathogens have emerged as an increasing risk faced by patients under sustained immunosuppression. Species of the Aspergillus family account for most of these infections and in particular Aspergillus fumigatus can be regarded as the most important airborne-pathogenic fungus. The improvement in transplant medicine and the therapy of hematological malignancies is often complicated by the threat of invasive aspergillosis. Specific diagnostics are still limited, as are the possibilities of therapeutic intervention. Hence, invasive aspergillosis is still associated with a high mortality rate that ranges from 30 % to 90 %. In recent years, considerable progress has been made in understanding the genetics of A. fumigatus and molecular techniques for the manipulation of the fungus have been developed. Molecular genetics offers not only approaches for the detailed characterization of gene products that appear to be key components of the infection process but also selection strategies that combine classical genetics and molecular biology to identify virulence determinants of A. fumigatus. The review discusses aspects of the current knowledge of the infection process, mechanisms of protection of the fungus against immune effector cells, and virulence determinants of A. fumigatus.

Pathophysiology of unilateral pulmonary aspergillosis in an experimental rat model

Because little is known about the pathophysiology of invasive pulmonary aspergillosis (IPA), we examined changes in pulmonary and general physiology during this disease in an animal model. In a model of fatal left-sided IPA, 19 persistently neutropenic rats were monitored for clinical signs including body temperature, body weight and respiratory distress. A separate group of nine rats with IPA was used for measurements of arterial blood pressure, arterial O2 and CO2 pressure, lung compliance and surfactant function. Body temperature and body weight decreased, whereas respiratory distress increased during progression of the disease. Compared to uninfected controls, in rats with IPA arterial blood pressure and lung compliance were significantly lower, and left lung minimal surface tension was significantly higher. Right lung surfactant function was not affected. Arterial O2 and CO2 pressures were not different between rats with IPA and uninfected controls. Infection with Aspergillus fumigatus in neutropenic rats resulted in hypothermia, body weight loss and respiratory distress. Loss of left lung function was probably compensated by the uninfected right lung, even in a late stage of the disease. Circulatory failure was a major feature in the terminal phase of the infection.

Pneumonectomy for complex aspergilloma: is it still dangerous?☆

OBJECTIVE

Pneumonectomy for complex aspergilloma is associated with high morbidity rates. This study aimed to improve the outcomes of this high-risk procedure by preventing postoperative complications.

METHODS

Between April 1999 and December 2004, 25 patients underwent pulmonary resection for complex aspergilloma at our institution. Of these patients, 11 (44%) patients (9 males and 2 females) undergoing a pneumonectomy were reviewed in this study. Median age was 63 years (range, 36-71 years). Associated pulmonary diseases were cavities secondary to tuberculosis (n=6) and a post-lobectomy destroyed lung (n=5). All patients presented with symptoms, including hemoptysis (n=10) and purulent sputum (n=1). To minimize the risk of empyema and bronchopleural fistula, careful extrapleural dissection and bronchial stump reinforcement with a latissimus dorsi muscle flap were employed in all patients. Follow-up was completed on March 31, 2005.

RESULTS

We performed six pneumonectomies (two right and four left) and five completion pneumonectomies (one right and four left). Operating time ranged from 361 to 781 min (median, 432 min). The median intraoperative blood loss was 1050 ml (range, 200-2910 ml). There was no operative mortality. No patient required re-exploration for postoperative hemorrhage. The major complications were empyema caused by anaerobic bacteria (n=1) and chylothorax (n=1). The treatment of both complications was successful. All patients were free from aspergillosis at the time of follow-up.

CONCLUSIONS

Pneumonectomy for symptomatic complex aspergilloma can be performed with no mortality and low morbidity. The favorable results of this potentially deleterious procedure hinge on the efforts to prevent postoperative complications.

Invasive aspergillosis in an immunocompetent host

Invasive aspergillosis is an uncommon opportunistic infection usually seen in immunocompromised patients. Despite extensive therapeutic measures the outcome is usually unfavourable. We report a case of invasive aspergillosis in an immunocompetent individual.

The invasive and saprophytic syndromes due to Aspergillus spp

Aspergillus spp. produce a wide range of invasive and sapropytic syndromes which may involve any tissue. Within a given tissue or organ the pathology and pathogenesis varies enormously, ranging from angioinvasive disease to noninvasive saprophytic disease. The individual invasive and saprophytic syndromes in which a causative role can be attributed to Aspergillus spp. are detailed specifically with reference to the underlying pathology and pathogenesis, the clinical setting and features, and the manner in which a diagnosis can be established.

The contribution of animal models of aspergillosis to understanding pathogenesis, therapy and virulence

Animal models of aspergillosis have been used extensively to study various aspects of pathogenesis, innate and acquired host-response, disease transmission and therapy. Several different animal models of aspergillosis have been developed. Because aspergillosis is an important pulmonary disease in birds, avian models have been used successfully to study preventative vaccines. Studies done to emulate human disease have relied on models using common laboratory animal species. Guinea pig models have primarily been used in therapy studies of invasive pulmonary aspergillosis (IPA). Rabbits have been used to study IPA and systemic disease, as well as fungal keratitis. Rodent, particularly mouse, models of aspergillosis predominate as the choice for most investigators. The availability of genetically defined strains of mice, immunological reagents, cost and ease of handling are factors. Both normal and immunosuppressed animals are used routinely. These models have been used to determine efficacy of experimental therapeutics, comparative virulence of different isolates of Aspergillus, genes involved in virulence, and susceptibility to infection with Aspergillus. Mice with genetic immunological deficiency and cytokine gene-specific knockout mice facilitate studies of the roles cells, and cytokines and chemokines, play in host-resistance to Aspergillus. Overall, these models have been critical to the advancement of therapy, and our current understanding of pathogenesis and host-resistance.

Taf1: a class II transposon of Aspergillus fumigatus

Aspergillus fumigatus is an important medical pathogen that lacks a known sexual cycle. Transposons may provide an important mechanism for the generation of genetic diversity in this organism. Here, we describe Taf1, the first class II transposon to be identified in A. fumigatus. Taf1, a member of the mariner superfamily and pogo family of transposons, is distinguished by the presence of extremely long (89 bp) inverted repeats that flank the transposase coding sequence. Taf1 is present in different locations and copy number among clinical strains of A. fumigatus and is transcribed. Analysis of multiple insertion sequences within a single strain suggests that Taf1 elements undergo inactivation by a repeat induced polymorphism-like mechanism. Taf1 insertion patterns were extremely stable despite multiple stressors including heat shock, serial passage, and infection in mice. Thus Taf1 may be useful for strain identification and molecular typing.

[Invasive pulmonary aspergillosis as a complication of prolonged antibiotic therapy]

In this study we present the case of 53 year old woman hospitalized in the Department of Lung Diseases and Tuberculosis in Zabrze, Silesian Medical University in Katowice, due to chronic cough and infiltration in the chest radiogram. Prior to the admission, the patient received long-lasting antibiotic ambulatory treatment leveled at laryngobronchitis. After admission the patient underwent bronchofiberoscopy during which a sample for mycological examination of bronchoalveolar lavage was taken. The result of the examination made possible to give the diagnosis--invasive pulmonary aspergillosis. Proper antifungal treatment was used and in consequence considerable improvement in both clinical and radiological state was achieved. Invasive pulmonary aspergillosis is mostly diagnosed in immunocompromised patients. The patient described in this case had none risk factors. Based on that particular case we may state a hypothesis that a prolonged antibiotic therapy is an important risk factor of invasive pulmonary aspergillosis incidence.

Predictors of pulmonary zygomycosis versus invasive pulmonary aspergillosis in patients with cancer

BACKGROUND

Pulmonary zygomycosis (PZ), an emerging mycosis among patients with cancer, has a clinical manifestation similar to that of invasive pulmonary aspergillosis (IPA). Most cases of PZ in such patients develop as breakthrough infections if treatment with antifungal agents effective against Aspergillus species is administered. However, clinical criteria to differentiate PZ from IPA are lacking.

METHODS

We retrospectively reviewed the clinical characteristics and computed tomography (CT) findings for 16 patients with cancer and PZ and for 29 contemporaneous patients with cancer and IPA at the time of infection onset (2002-2004). Patients with mixed infections were excluded. Parameters predictive of PZ by univariate analysis were included in a logistic regression model.

RESULTS

Almost all patients with PZ (15 of 16) and IPA (28 of 29) had underlying hematological malignancies and typical risk factors for invasive mold infections. In logistic regression analysis of clinical characteristics, concomitant sinusitis (odds ratio [OR], 25.7; 95% confidence interval [CI], 1.47-448.15; P = .026) and voriconazole prophylaxis (OR, 7.76; 95% CI, 1.32-45.53; P = .023) were significantly associated with PZ. The presence of multiple (> or = 10) nodules (OR, 19.8; 95% CI, 1.94-202.29; P = .012) and pleural effusion (OR, 5.07; 95% CI, 1.06-24.23; P = .042) at the time that the patient underwent the initial CT were both independent predictors of PZ in the logistic regression analysis of radiological parameters. No difference occurred in the frequency of other CT findings suggestive of pulmonary mold infections (e.g., masses, cavities, halo sign, or air-crescent sign) between the 2 patient groups.

CONCLUSIONS

PZ in immunocompromised patients with cancer could potentially be distinguished from IPA on the basis of clinical and radiological parameters; prospective validation is needed.

Patulin produced by an Aspergillus clavatus isolated from feed containing malting residues associated with a lethal neurotoxicosis in cattle

A severe neurotoxicosis, comprising tremors, ataxia, paresis, recumbency and death, occurred simultaneously among several herds of beef cattle in the region of Flanders (Belgium). After a first multi-toxin screening of some suspected diet elements, verruculogen was detected in a sample of a common feed ingredient. However, when the first animal necropsies revealed serious nervous lesions, including neuronal degeneration of the central nervous system and axonal degeneration in the peripheral nervous system, further investigations focused on fungal isolation. As expected from the pathological lesions, Aspergillus clavatus was found to be the dominant fungal species in a sample of compacted fodder, containing malting residues, consumed by all the affected herds. The isolated fungus appeared to produce patulin in culture medium. Traces of patulin were also detected in the fodder. These findings and their possible role in the intoxication are discussed.

Invasive Tracheobronchial Aspergillosis in an Immunocompetent Person

Tracheobronchial involvement is an uncommon form of invasive pulmonary aspergillosis and is found mainly in immunocompromised individuals such as patients with leukemia and prolonged granulocytopenia due to cytotoxic therapy, organ transplant recipients receiving high-dose corticosteroids, or patients with chronic granulomatous diseases. Rarely, such a pattern can also be seen in immunocompetent persons or can involve atypical sites such as the paranasal sinuses, skin, and the tracheobronchial tree. Occasionally, these patients require a prolonged course of antifungal agents. We report a case of aspergillosis involving the tracheobronchial tree in an immunocompetent young male that presented a diagnostic dilemma.

Correlations between clinical and laboratory findings in patients investigated for aspergillosis

We investigated 120 patients suspected clinically to have pulmonary aspergillosis with different clinical manifestations "aspergilloma (Subgroup A), allergic bronchopulmonary aspergillosis (Subgroup B) and invasive pulmonary aspergillosis (Subgroup C)" and correlated between their clinical and laboratory findings and endogenous specific aflatoxin production. They were subjected to isolation of Aspergillus strains, measurement of serum total IgE and specific Aspergillus IgG by ELISA and identification of aflatoxin producing Aspergillus strains using fluorescence analysis of spectroline. Aspergillus was isolated from 45 patients (37.5%). Subgroup A had a negative statistically non-significant correlation between clinical and laboratory findings as regard total IgE and for Aspergillus IgG (only haemoptysis &weight loss had significant correlation with aspergillus IgG). Subgroup B & Subgroup C had positive, statistically significant correlation &negative statistically non significant correlation respectively as regard all clinical findings and both total IgE & serum IgG. This study also showed that 6 Aspergillus strains out of 45(13.3%) produced endogenous aflatoxin. It is concluded that a significant correlation that exists between clinical and serological findings in allergic pulmonary aspergillosis. Aflatoxins may be produced in vivo by strains of Aspergillus and may result in manifestations similar to those caused by ingestion of aflatoxin in food.

Retinal Function Assessed by ERG Before and After Induction of Ocular Aspergillosis and Treatment by the Anti-fungal, Micafungin, in Rabbits

This study was conducted to evaluate the effectiveness of a new antifungal drug, micafungin, and standard antifungal drugs against endophthalmitis induced in a rabbit by intravitreal injection of Aspergillus fumigatus, an important fungal pathogen. Effectiveness was evaluated by the preservation of b-wave amplitude at 72 h after injection of the fungus relative to the b-wave amplitude at baseline before any intravitreal injections. A 0.06 ml inoculum of 10(6) conidia of A. fumigatus was injected into the vitreous of the right eye of all rabbits; and, 12 h later, a 0.06 ml solution containing one of 3 antifungal drugs or saline was injected into the vitreous of both eyes. All three antifungal drugs produced significant b-wave preservation at 72 h in infected eyes compared to that in infected eyes receiving saline injections. There was no statistically significant difference between the effects of micafungin and amphotericin B in the right eyes with fungal endophthalmitis, and both produced significantly more preservation of b-wave amplitude than voriconazole. Amphotericin B, but neither micafungin nor voriconazole produced significant reduction of the b-wave amplitude in the left eyes.

The future of animal models of invasive aspergillosis

The diagnosis of invasive aspergillosis remains very difficult, coupled with limited treatment options. Animal models have been utilized to evaluate both the diagnosis and treatment of infection and to assess the pathogenicity and virulence of the organism. However, animal models have not been standardized and have been used in only a limited fashion for genomic evaluation in this disease. Extensive efforts are underway to expand significantly the Aspergillus genomic information. Thus, the standardization of animal models of invasive aspergillosis is critical to create a unified platform to enhance evaluation of newer genomic information and allow assessment of pathogenicity and virulence factors. Proposed models, supported by a recently awarded National Institutes of Health/National Institute of Allergy and Infectious Diseases contract, will be developed in close interaction with the extended Aspergillus community (including academia and industry) to answer key questions in this disease. The goal of this work is to provide the framework to evaluate genomic targets in animal models in order to improve the diagnosis and treatment of invasive aspergillosis that will ultimately result in improved outcomes of patients with this frequently fatal infection.

Aspergillous sinusitis

Chronic invasive aspergillous sinusitis is an uncommon disease that usually occurs in healthy individuals. Chronic invasive aspergillus sinusitis is inadequately characterized entity. Despite its rarity, it is going to be recognized increasingly. We report a neglected patient who received several courses of antibiotics before definite diagnosis. Clinical manifestations, differential diagnosis and treatment are discussed. A high degree of awareness for an early diagnosis may participate to improve the poor prognosis.

Pathophysiology of pulmonary aspergillosis

A description of the pathophysiology of aspergillosis is followed by a review of investigational considerations of animal models. Because a large body of invasive Aspergillus infection occurs as opportunistic infection, there is a large spectrum of the histopathological feature of lesions demonstrated at the site of infection. Histopathology of the lesions can be understood as a phenotypical representation of interaction between lowered defense mechanisms in the host and the virulence of invading fungi. Detailed observations with a consideration of previous pathological knowledge of infection and inflammation provide much important information useful in predicting the pathophysiology of the patient. Moreover, experimental studies can also provide much insight to elucidate pathogenesis of the infection that emerges from the clinical and pathological investigations. The importance of pathophysiology should be emphasized to understand the implications of radiographic images, clinical symptoms, and laboratory dates. By reviewing these, especially computed tomography (CT) images, we can see that they accurately mirror the histological features of the lesion that can be recognized as a phenotypical representation of pathophysiology of Aspergillus infection. This is also confirmed by the reports emphasizing the importance of CT scans to identify hallmark clinical signs and symptoms of the disease.

Aspergillose pulmonaire invasive chez les enfants immunodeṕrimés méthodes diagnostiques et classification

Invasive aspergillosis is an opportunistic infection, with frequent lung involvement. High-risk children are allogenic bone marrow recipients, and those with hematological malignancies, aplastic anemia or chronic granulomatous disease. Profound and prolonged neutropenia, and corticosteroid therapy are the most important predisposing factors. Building and demolition works represent the major environmental risk factor. The diagnosis of invasive aspergillosis remains difficult to establish. Clinical manifestations are non-specific. Early thoracic computed tomographic scan shows halo sign in most cases. Subsequently appears the air crescent sign. Galactomannan research by sandwich ELISA can be useful in serum and in bronchoalveolar lavage fluid. Aspergillus DNA detection by PCR is still not standardized. Culture of the organism allows species identification. Aspergillus hyphae can be found at cytological examination, but a biopsy specimen is usually required to affirm tissue damage. A new classification of invasive fungal infections in immunocompromised patients was recently proposed by experts from the European Organization for Research and Treatment of Cancer and from the Mycoses Study Group of the National Institute of Allergy and Infectious Diseases. On the basis of host linked criteria, microbiological, clinical and radiological features, invasive aspergillosis is classified as proven, probable or possible. These definitions should not be used to guide clinical practice in therapy, but they will improve the quality of epidemiological data, and help the comparison of clinical trial results.

[Early description of a pulmonary aspergillosis 1847 from Greifswald]

In 1847 the student of medicine Theodor Sluyter (1817-1895) from Greifswald published his thesis in Berlin including the first well-documented case of human pulmonary aspergillosis. In 1856 Rudolf Virchow (1821-1902) classified the depicted fungi as an Aspergillus species. Possibly Carl Ferdinand Eichstedt (1816-1892) carried out the autopsy. He is known by the first description of a fungus as the cause of pityriasis versicolor in 1846. Further involved scientists from Greifswald were Wilhelm Baum (1799-1883), Theodor Litzmann (1815-1890) and the botanist Johann Konrad Schauer (1813-1848). Their curricula vitae are given in further details as well the curriculum of T. Sluyter.

Invasive aspergillosis in the setting of cardiac transplantation

Among patients undergoing heart transplantation, Aspergillus is the opportunistic pathogen with the highest attributable mortality. The median time of onset from transplantation for invasive pulmonary aspergillosis (IPA) was 46 days, but the median time to first positive culture result was 104 days among patients with Aspergillus colonization but no invasive disease. Most patients with IPA presented with fever and cough within the first 90 days of transplantation and with single or multiple pulmonary nodules. None of the heart transplant recipients with either IPA or invasive extrapulmonary aspergillosis (IEPA) had associated neutropenia. Human leukocyte antigen A1 locus was found significantly more frequently among patients colonized with Aspergillus than among patients with IPA (P<.006) or IEPA (P<.001). Even in the absence of neutropenia, IPA should be suspected for heart transplant recipients who have fever and respiratory symptoms within the first 3 months of transplantation, have a positive result of culture of respiratory secretions, and have abnormal radiological findings (particularly nodules).