Environmental factors in allergic bronchopulmonary aspergillosis

Many workers have suggested that exposure to an environment rich in Aspergillus spores is aetiologically significant in allergic bronchopulmonary aspergillosis. This hypothesis has been investigated by means of an environmental survey in which eight urban dwelling patients with this disease and five atopic control patients took part. Enquiries were made about contact with known sources of Aspergillus fumigatus and air spora studies were conducted in the home. Findings were similar for both groups. No high spore concentrations were recorded in the homes of either group. Patients with allergic bronchopulmonary aspergillosis had not been more exposed to potentially rich sources of A. fumigatus than the atopic control patients. The view is expressed that specific host susceptibility is more important in the pathogenesis of allergic bronchopulmonary aspergillosis than environmental factors. Once a patient is sensitized however minor increases in spore concentration can cause symptomatic disease producing the recognized winter exacerbations of allergic bronchopulmonary aspergillosis. Possible mechanisms allowing the development of the disease in the presence of low spore concentrations are discussed.     

High fungal spore burden with predominance of Aspergillus in hospital air of a tertiary care hospital in Chandigarh

The prevalence of fungal spores in the hospital air is essential to understand the hospital-acquired fungal infections. Air conditioners (ACs) used in hospitals may either reduce spores in air or be colonised by fungi and aid in its dissemination. The present study was conducted to assess the fungal spore burden in AC and non-AC areas. We found a high fungal spore count in air irrespective of whether the area was AC or non-AC. The most predominant species isolated were Aspergillus flavus and Aspergillus fumigatus. Such high concentrations of pathogenic fungi in air may predispose individuals to develop disease.     

Fungal spores in lung and sputum

A survey of fungal aerospora over a 2-year period was combined with an investigation of the fungi cultured from 295 samples of peripheral human lung and 2466 samples of sputum over the same period. 83% of lung and 88% of sputum samples contained culturable fungi, although in 16% of lung and 31% of sputum samples Candida albicans was the only one. Those fungi of small spore size tended to be found in lung tissue while those with larger spores were more likely to be found in the sputum. While their presence in the respiratory tract was related to their occurrence in the air, differences in their frequencies in the air and lung suggested that the lung had a selective inhibitory effect on the development of different spores. In particular, Aspergillus fumigatus was cultured more frequently than would have been anticipated from its profusion in the air.     

Interaction of Aspergillus fumigatus Spores with Human Leukocytes and Serum

Serum was necessary for optimal phagocytosis of Aspergillus fumigatus spores by human leukocytes, and its opsonic capacity was greatly diminished by heat inactivation (56 C, 30 min). A germination assay, described in this report, was developed to study the fate of phagocytized spores. After incubation for 3 hr with normal leukocytes and serum, spores ingested by peripheral blood neutrophils and monocytes remained viable. Since we had previously found that myeloperoxidase (MPO), a lysosomal enzyme of human neutrophils and monocytes, exerted fungicidal activity against Candida albicans when combined with H₂O₂ and chloride or iodide, the effects of these substances on A. fumigatus spores were examined. Spore viability was not impaired by MPO alone, H₂O₂ alone, or KI alone, but high concentrations of KI and H₂O₂ in combination caused marked inhibition of subsequent germination. MPO imparted fungicidal activity to concentrations of KI and H₂O₂ that lacked any effect in its absence. NaCl, in combination with MPO and H₂O₂, was far less effective than the iodide salt against A. fumigatus. The relative ineffectiveness of chloride in this system could underly the apparent inability of human neutrophils to kill ingested A. fumigatus spores, despite their competence to kill C. albicans.     

Purified Recombinant A. fumigatus Allergens Induce Different Responses in Mice

Aspergillus fumigatus an opportunistic fungus is associated with a number of diseases in humans. Allergy resulting from exposure to the A. fumigatus allergens has been recognized frequently. The damage caused by the disease is very striking in patients with atopy and those with cystic fibrosis. Avoidance to exposure is not feasible because A. fumigatus spores are ubiquitously distributed in the environment. Hence, immunotherapeutic regimens in severe forms of A. fumigatus allergy may have a high potential. However, before such forms of therapy can be envisaged, it is essential to understand the immunopathogenesis. In the present study, we investigated the role of purified A. fumigatus allergens in the development of allergic asthma in mice. We have used four major recombinant A. fumigatus allergens in the murine model. Mice exposed to Asp f 1, f 3, and f 4 showed inflammatory changes in the lungs and airway hyperreactivity. The immune responses, including elevated serum IgE, enhanced eosinophils, recruitment in the peripheral blood and lungs, and expression of regulatory cytokines, are characteristic of a Th2 response. Asp f 6 demonstrated only a reduced response in these animals. The results suggest that the pathology induced by crude A. fumigatus extract results from the cumulative effects of the allergens and the individual responses varied considerably with different purified antigens.     

Longitudinal study ofAspergillus fumigatus strains isolated from cystic fibrosis patients

The colonization over time of cystic fibrosis patients byAspergillus fumigatus was investigated using a DNA fingerprinting method.Aspergillus fumigatus isolates collected sequentially for more than one year from six patients with cystic fibrosis were typed by Southern blot hybridization with a repetitive DNA sequence. Each cystic fibrosis patient harbored several strains ofAspergillus fumigatus that were isolated recurrently over time. Isolates collected from a cystic fibrosis patient with aspergilloma displayed the same genotype, suggesting that the infection was due to a single strain. Continuous isolation of the same genotype in another cystic fibrosis patient, however, was not correlated clinically with anAspergillus infection.     

Protease-dependent activation of epithelial cells by fungal allergens leads to morphologic changes and cytokine production

Background: Proteases in extracts of Aspergillus fumigatus cause epithelial cell desquamation and release of proinflammatory cytokines. Objective: We sought to assess protease activity in Alternaria alternata , Cladosporium herbarum , and Aspergillus fumigatus extracts and study the ability of these extracts to cause desquamation and release of proinflammatory cytokines from epithelial cells. Methods: Protease activities of the fungal extracts were quantified. Changes with respect to cell morphology, cell desquamation, and cytokine production (IL-6 and IL-8) were measured in the absence and presence of the fungal extracts in an airway-derived epithelial cell line (A549) and primary epithelial nasal cells. Results: Fungal proteases differentially induced morphologic changes, cell desquamation, and production of IL-6 and IL-8 in a dose- and time-dependent fashion. Alternaria alternata extracts induced cell shrinking and cell desquamation and strongly enhanced the production of IL-6 and IL-8 at higher concentrations. Aspergillus fumigatus extracts caused cell shrinking, cell desquamation, and production of IL-6 and IL-8, even at low concentrations. The Aspergillus fumigatus –derived extract grown on collagen medium induced a strong dose-dependent decline in cytokine production at higher concentrations. Cladosporium herbarum extracts did not induce morphologic changes or cell desquamation but enhanced IL-6 and IL-8 productions at higher concentrations. The dependence of these effects on intact protease activity was shown by their abrogation by protease inhibitors. Conclusion: Proteases present in fungal extracts interact with epithelial cells, leading to morphologic changes, cell desquamation, and induction of proinflammatory cytokines. It is proposed that these fungal proteases may activate epithelial cells through a protease-activated receptor type 2–driven mechanism. (J Allergy Clin Immunol 2000;105:1185-93.)     

Prevalence of precipitins in groups at risk of developing hypersensitivity pneumonitis

A study was made of the prevalence of serum precipitins to Micropolyspora faeni, Thermoactinomyces vulgaris, Aspergillus fumigatus, and pigeon serum in population groups suspected to be at high risk for the development of hypersensitivity pneumonitis. Pigeon breeders' sera contained precipitins mainly to pigeon serum (38%) and A. fumigatus (18%). Occupants of homes in which forced air heating systems were investigated for the presence of microorganisms reacted mostly with M. faeni (13%) and A. fumigatus (8%). Individuals from environments where several cases of hypersensitivity pneumonitis were discovered reacted largely with M. faeni (28%) and T. vulgaris (21%). Sera supplied by physicians from patients with respiratory symptoms reacted primarily to A. fumigatus (24%) and to a lesser extent to M. faeni (16%) and T. vulgaris (9%). The results indicate that the prevalence of precipitins to the tested antigens is not uniform and may be influenced by the environment. Furthermore, the prevalence of precipitins in groups at risk is greater than previously reported for the normal population.     

Susceptibility of adult pigeons and hybrid falcons to experimental aspergillosis

Aspergillosis caused by Aspergillus fumigatus seems to be more prevalent in some avian species than in others. We compared the development of aspergillosis in 8-month-old Gyr-Saker hybrid falcons and 8-month-old pigeons after a single intratracheal inoculation of different dosages of A. fumigatus conidia (10⁷, 10⁵ and 10³). Clinical signs, including vomiting, discoloration of the urates, loss of appetite and dyspnoea, were observed in four out of five falcons and in four out of five pigeons inoculated with 10⁷ A. fumigatus conidia. Necropsy revealed the presence of granulomas in the air sacs and/or lungs in four out of five falcons and in four out of five pigeons in the high dosage group. A. fumigatus was isolated from these granulomas in three falcons and in three pigeons. The presence of fungal hyphae was detected with Periodic acid Shiff reagent staining in three out of five falcons and in three out of five pigeons in the high dosage group. Avian respiratory macrophages were clearly present in and around the fungal granulomas. In the other dosage groups, no granulomas, positive A. fumigatus cultures or fungal hyphae were present, except for one falcon in the middle dosage group in which a sterile granuloma without fungal hyphae was noticed. In conclusion, the study shows that adult falcons and pigeons are susceptible to aspergillosis after inoculation of a single dose of conidia intratracheally.     

Aspergillus pleural empyema in a chronic smoker – A case report and review of literature

Aspergillus species are ubiquitous saprophytic fungi that are present in the air, water, soil, and decaying vegetables. Clinical features of Aspergillus infection largely depend on the interplay between the fungi and the host immune status.We present a case of a chronic smoker with shortness of breath who was found to have diffuse bronchiectatic changes and empyema of the right lung. Emphysema was also noticed in the left lung. Rare Aspergillus fumigatus was identified in the pleural fluid, while the acid-fast stain and bacterial cultures were negative. The patient's serum Aspergillus fumigatus IgG antibody and galactomannan antigen were negative; however, the pleural galactomannan antigen was elevated. He was treated with video-assisted thoracoscopic surgery (VATS) and partial decortication of the right lung, along with intravenous voriconazole. Despite aggressive therapeutic measures, he died after a prolonged hospital stay.Aspergillus pleural empyema is rare but can be fatal; however, it is not included in the classification for pulmonary aspergillosis. Clinicians should be vigilant to evaluate for fungal empyema in patients with chronic obstructive pulmonary diseases, even without profound immunosuppression.     

Aspergillus fumigatus spore concentration in outside air: Cardiff and St Louis compared

Intermittent sampling of the atmosphere 3 days/week over a 12-month period using Andersen samplers in Cardiff, Wales, U.K. and St Louis, Missouri, U.S.A., indicated average A. fumigatus spore concentrations of 13.5/m³ in St Louis and 11.3/m³ in Cardiff. Both sites showed seasonal variations with highest concentrations during winter.     

Thermotolerant mycobiota of Israeli soils

Composition of thermotolerant mycobiota in the soil of Israeli deserts and northern territories was examined in spatiotemporal dynamics. A total of 165 species from 82 genera were isolated at 37 °C using the soil dilution plate method. Aspergilli (Aspergillus fumigatus and A. niger) and teleomorphic ascomycetes (Canariomyces notabilis, Chaetomium nigricolor, and Ch. strumarium) comprised the basic part of the thermotolerant communities. The desert communities remarkably differed from the northern communities by a much higher abundance of A. fumigatus and teleomorphic species, as well as by a lower abundance of A. niger and Rhizopus arrhyzus. Seasonal dynamics revealed for the southern Negev was expressed mainly in the variations of species richness (substantially lower in the winter), and abundances of A. fumigatus (dominant in the summer) and A. niger (dominant in the winter). The composition of thermotolerant mycobiota was almost entirely different from the composition of mesophilic mycobiota at 25 °C. Melanin‐containing fungi with many‐celled conidia that dominated mesophilic communities in the deserts did not grow at 37 °C, while prevailing aspergilli accompanied by teleomorphic species with perithecial fruit bodies were apparently able not only to survive but also to germinate at this temperature and be active during a long hot period in the desert.     

Aspergillus infections in birds: a review

Aspergillosis is an infectious, non-contagious fungal disease caused by species in the ubiquitous opportunistic saprophytic genus Aspergillus, in particular Aspergillus fumigatus. This mycosis was described many years ago, but continues to be a major cause of mortality in captive birds and, less frequently, in free-living birds. Although aspergillosis is predominantly a disease of the respiratory tract, all organs can be involved, leading to a variety of manifestations ranging from acute to chronic infections. It is believed that impaired immunity and the inhalation of a considerable amount of spores are important causative factors. The pathogenesis, early diagnostic methods and antifungal treatment schedules need to be further studied in order to control this disease. The aim of the present review is to present the current knowledge on aspergillosis with the main emphasis on A. fumigatus infections in captive and free-living birds rather than domestic poultry. The review covers aetiology, epidemiology, pathogenesis, clinical signs and lesions, diagnosis, treatment and prevention.     

Modelling Aspergillus fumigatus infections in racing pigeons (Columba livia domestica)

In vivo modelling of aspergillosis in birds allows the evaluation of control measures and the study of host–pathogen interactions. In this study the impact of the use of different inoculation routes and immunosuppression on the course of an infection with Aspergillus fumigatus in racing pigeons (Columba livia domestica) was examined. A. fumigatus conidia were inoculated in the thoracic air sac, lung or trachea in immunocompetent or immunosuppressed pigeon squabs. Immunosuppression was induced by three dexamethasone injections before inoculation. Mortality in the A. fumigatus-inoculated groups varied between 1/4 and 4/4. The highest and more acute mortality was seen in immunocompetent pigeons inoculated in the thoracic air sac and in pigeons inoculated in the thoracic air sac or lung after immunosuppression. Pigeons inoculated in the lung or inoculated intratracheally after immunosuppression developed an aspergillosis infection with a slower course of disease and more prominent clinical symptoms. Using microsatellite length polymorphism, it was confirmed that all mycoses were caused by the inoculated strain except for one isolate in a dexamethasone-treated pigeon. In conclusion, inoculation in the lung is selected as the preferred model for chronic aspergillosis in pigeons, and inoculation in the thoracic air sac as the preferred model for acute aspergillosis. The use of immunosuppressed birds seems to be contra-indicated due to the risk of opportunistic infections.     

Clinical Significance of Scedosporium apiospermum in Patients with Cystic Fibrosis

 The incidence of airway colonization by Scedosporium apiospermum and of related sensitization was investigated prospectively in 128 patients with cystic fibrosis over a 5-year period, and results were compared with clinical data. Scedosporium apiospermum, recovered from sputum samples in 11 of 128 (8.6%) patients, was the most frequent filamentous fungus after Aspergillus fumigatus. Counterimmunoelectrophoresis, used to detect scedosporiosis serologically, was positive in 27 of 128 (21.1%) patients. The discrepancy between the mycological and serological results may be related to immune cross-reactions between Scedosporium apiospermum and Aspergillus fumigatus. However, symptoms of allergic bronchopulmonary disease were observed in two patients chronically colonized by Scedosporium apiospermum. The results clearly demonstrate that the frequency of this fungus is largely underestimated and that it may trigger an inflammatory response, thus suggesting a pathogenic role in patients with cystic fibrosis.     

Allergic broncho-pulmonary aspergillosis

In IU out of 143 U.K. patients with pulmonary eosinophilia evidence of allergic broncho-pulmonary aspergillosis was present, consisting of transitory pulmonary shadows, eosinophilia of blood and sputum. Type I and Type HI reactions to prick and intracutaneous tests respectively with A. fumigatus. Precipitins were present in 92% of sera tested with and without concentration. Sputum plugs usually with pulmonary shadows were present in 56% and contained fungal mycelium, and the sputum gave positive cultures in 58%. Characteristic proximal bronchiectasis was present and fibrosis, mainly of the upper lobes, was found in chronic cases. These features were absent in the patients with no evidence of allergy to A. fumigatus. Patients with early onset of symptoms had a higher atopic status and a much longer interval before pulmonary eosinophilia appeared than those with late onset symptoms. Episodes of pulmonary eosinophilia with aggravation of all symptoms, with fever and positive cultures in 83% for A. fumigatus, were common in the winter months, when there are more spores in the air. Precipitins to one or more of H. influenzae, Str. pneumoniae and Staph. aureus were present in 60% of sputa examined and positive cultures were obtained in 45%, indicating a high incidence of secondary infection. Increasing airways obstruction with decreasing reversibility was common and some had reduction of CO gas transfer factor. Pulmonary hypertension was uncommon. Corticosteroids reduced sputum plugs, positive cultures and hastened resolution of pulmonary shadows. Diagnoses such as pneumonia, tuberculosis, bronchiectasis and carcinoma were not uncommonly made before that of allergic broncho-pulmonary aspergillosis.     

Significance of<Emphasis Type="Italic"> Aspergillus fumigatus</Emphasis> Isolation from Respiratory Specimens of Nongranulocytopenic Patients

The aim of this study was to determine the significance of isolation of Aspergillus fumigatus from cultures of respiratory specimens in nongranulocytopenic patients. The medical records of patients with respiratory specimens positive for Aspergillus fumigatus who were admitted to an adult pneumology ward were reviewed during a 2-year period. A total of 80 respiratory specimens from 76 patients yielded Aspergillus fumigatus. Forty-eight patients were colonized with Aspergillus fumigatus, whereas the 28 (37%) remaining patients had pulmonary aspergillosis, manifest as aspergilloma (n=19 patients), chronic necrotizing pulmonary aspergillosis (n=7 patients), and bronchial aspergillosis (n=2 patients). The presence of typical hyphae in direct examination of bronchoscopic specimens was more likely to be found in infected than in colonized patients (P=0.04). No immunological test was positive in colonized patients, whereas anti-Aspergillus antibodies were detected in 55% of infected patients (P<0.001). Pulmonary tuberculosis was the most common underlying lung disease in patients with aspergilloma, but it was not found in any patient with chronic necrotizing pulmonary aspergillosis (P=0.006). Anti-Aspergillus antibodies were more likely to be detected in patients with aspergilloma (78%) than in patients with chronic necrotizing pulmonary aspergillosis (14%) (P=0.007). The analysis of predisposing factors, in conjunction with immunological tests and examination of bronchoscopic specimens, is helpful in distinguishing between colonization and infection with Aspergillus fumigatus, as well as for differentiating between aspergilloma and chronic necrotizing pulmonary aspergillosis.This work was presented in part at the 5^th Congress of the European Confederation of Medical Mycology, Dresden, Germany, 1999     

Genetic susceptibility to infections with Aspergillus fumigatus

Infections with the opportunistic mold Aspergillus fumigatus show high morbidity and mortality. Risk factors for the development of invasive aspergillosis are neutropenia, T-cell depletion, CD34-selected stem cell products, corticosteroid therapy, and cytomegalovirus infections.

Recently, a growing number of defined single nucleotide polymorphisms have been described that genetically determine susceptibility to A. fumigatus. This includes genes encoding for cytokines or chemokines and their receptors, toll-like receptor genes, and other genes involved in innate immunity.

This review summarizes the current knowledge about the growing number of genetic markers and their relevance for the course and outcome of infections with A. fumigatus.     

Saprophytic fungi and the deterioration of malting grains of Sorghum guineense Stapf

The ability of Humicola insolens Cooney & Emerson and Aspergillus fumigatus Fres. to cause biochemical changes in the components of milled Sorghum guineense grains and the factors necessary for these activities were studied. Significant losses (at p = <0.01) in the cellulose, hemicellulose, diastase and ethanol soluble fractions of the malted grains were recorded on inoculation with asexual spores of A. fumigatus and H. insolens and 21 days of incubation at 35 °C and 45 °C, respectively. This was accompanied by a corresponding rise in the total nitrogen components of the medium with period of incubation. None of the microbes was able to degrade the lignin components of the malted grains. While A. fumigatus was most active on the grains at 35 °C and pH 6.2, H. insolens grew best at 45 °C and pH 5.4. When both fungi were grown on varying sources of carbon and nitrogen good results were obtained on most of them with optimal growth recorded on starch and dextrin and the organic nitrogen sources l-asparagine, l-glutamic acid and l-alanine. Both fungi also produced extracelluearly amylase, cellulases, pectate lyase, xylanase, protease, lipase, DNase and RNase. The potential health risks which the presence of these fungi on malted Sorghum grains pose to the consumers of the end products are discussed.