Aspergillus Fumigatus Isolates Research Articles

The isolation and identification of a new metabolite from Aspergillus fumigatus related to gliotoxin

Summary Gliotoxin G, the tetrasulphide analogue of gliotoxin has been characterized from a laboratory isolate of Aspergillus fumigatus .

Frequency of Aspergillus fumigatus isolates and antibodies to aspergillus antigens in cystic fibrosis.

The frequency of Aspergillus fumigatus isolates from sputum was assessed prospectively during a 22-month period in 156 patients with cystic fibrosis (CF) from one center, and findings were compared to a cross-sectional evaluation of specific IgG and IgA antibodies, occurrence of chronic Pseudomonas aeruginosa infection, and pulmonary function. The prevalence rate for the 22-month period was 40%. Positive A. fumigatus cultures appeared to be independent of the presence or duration of chronic bronchopulmonary Ps. aeruginosa infection, but isolation of A. fumigatus in patients with pseudomonas infection for more than 5 years was associated with notably decreased pulmonary function. Levels of IgG antibodies to a 470,000 daltons A. fumigatus antigen fraction were higher in patients with positive cultures in the observation period than in those without. IgG antibodies to a 25,000-50,000 daltons antigen fraction were directly correlated to A. fumigatus frequency in patients with positive cultures both prior to and during the survey. On the other hand, levels of IgA antibodies to the 470,000 daltons fraction were inversely related to A. fumigatus frequency, suggesting a role of IgA antibodies in the bronchial clearance of aspergilli. Decreased pulmonary function was found to be associated with elevated levels of A. fumigatus antibodies. It is concluded that immune reactions elicited by A. fumigatus may play a role in clearance of the fungus from the airways but also may contribute to lung morbidity in some patients.

Comparative Pharmacokinetics of Antifungal Drugs in Domestic Turkeys, Red-Tailed Hawks, Broad-Winged Hawks, and Great-Horned Owls

The present research was to test in vitro activity of thiabendazole, 5-fluorocytosine, and amphotericin B against 11 isolates of Aspergillus fumigatus from avian species. Additionally, the plasma concentrations of these drugs were determined in four avian species given a range of dosages by oral, intravenous, and intratracheal routes. Thiabendazole inhibited most isolates in vitro at concentrations between 25 and 50 micrograms/ml; however, there were no detectable inhibitory concentrations in the plasma of any species at any of the doses. The arithmetic mean minimum inhibitory in vitro concentration for 5-fluorocytosine against the 11 Aspergillus isolates was 2.73 micrograms/ml. Inhibitory concentrations of 5-fluorocytosine were found 2 and 6 hours post-administration in all species when given oral doses of 30 or 60 mg/kg as a single dose or when given three divided doses a day totaling 120 mg/kg. No inhibitory concentrations were found 24 hours post-administration. Inhibitory concentrations of amphotericin B were found only 2 and 6 hours post-administration in birds receiving three doses of 1.5 mg/kg at 2-hour intervals. The arithmetic mean minimum inhibitory in vitro concentration for amphotericin B against 11 isolates of A. fumigatus was 0.81 micrograms/ml.

In vitro susceptibility studies with oxiconazole (Ro 13-8996).

Oxiconazole (Ro 13-8996) is a recently described imidazole derivative intended for topical use. 128 isolates of pathogenic fungi were tested in vitro against oxiconazole, miconazole, and ketoconazole using an agar dilution method. Results indicated that miconazole was markedly more active than either oxiconazole or ketoconazole against Candida albicans while ketoconazole was the more active compound against Candida parapsilosis. A species specific difference in the susceptibilities of isolates of Aspergillus fumigatus and Aspergillus flavus to all three imidazoles with A. flavus being more susceptible was noted. Both Mucor and Rhizopus were more susceptible to oxiconazole than to either miconazole or ketoconazole. There were no noticeable differences among the dermatophytes in tests with the three drugs with all geometric mean minimum inhibition concentrations (MIC) being less than 1.0 micromilligram-1. The dematiaceous fungi also demonstrated no major differences in susceptibility to the three drugs. One isolate of Pseudallescheria boydii was relatively resistant to all three drugs (MIC greater than or equal to 16 micromilligrams-1).

Serodiagnostic value of culture filtrate antigens from aspergilli with septate phialides.

Culture filtrate antigens from 6 typical isolates of Aspergillus fumigatus, 6 isolates with septate phialides, and isolates of A. fumigatus var. ellipticus, A. fishceri, A. flavus and A. niger were studied in tests with 2,100 samples of serum originating from 1,452 patients suffering from miscellaneous diseases, including 60 cases of aspergillosis, 850 samples of serum from apparently healthy blood donors and 522 sera referred to us as positive for C-reactive protein. The culture filtrate antigen prepared from a septate-phialide-strain proved to be most useful in detecting precipitating antibodies in the sera of patients suffering from aspergillosis caused by A. fumigatus. The antigen from this strain not only gave sharper and a larger number of precipitin bands than others but also proved to be an invaluable tool in the serodiagnosis of 5 to 56 (8.9%) A. fumigatus cases in which all other antigens repeatedly failed to give a positive result. The serological data also suggest that the septate-phialide strains are mutants of A. fumigatus and should not be classified as a separate species.

Survey of human pathogenic actinomycetes and fungi in soil from Rome and other Italian areas.

As part of a study sponsored by the Ministry of Health of Italy, a research program on pathogenic actinomycetes, keratinophilic and pathogenic fungi in soil was carried out. Two hundred soil samples, collected from different areas of the city of Rome, Calabria, Emilia Romagna, Latium, Apulia, Sardinia, Sicily, Tuscany and Umbria, were examined by several techniques to detect the widest possible variety of pathogenic actinomycetes and fungi. Seven isolates of Nocardia asteroides, four of Actinomadura madurae and one of Nocardiopsis dassonvillei were isolated for the first time from soil in Italy. In addition, numerous isolates of Petriellidium boydii, Aspergillus fumigatus, A. flavus, A. niger and keratinophilic fungi of the genera Microsporum, Trichophyton and Chrysosporium were also recovered.

Detection of antibodies to Aspergillus fumigatus in agar gel with different antigens and immunodiffusion patterns

A comparison was made of antigens prepared in various ways in the Mycological Reference Laboratory (MRL) and obtained commercially from Bencard, London; and the Institut Pasteur, Paris, France. The standard well pattern in use in the MRL was also compared with the Bencard pattern and the Institut Pasteur pattern, using all the antigens. It was found that the use of antigens from two isolates of Aspergillus fumigatus gave the maximum number of positive results. Antigens prepared in other ways, and the commercial antigens, did not give a significantly higher number of additional positive reactions. There was little difference between the results obtained with the three patterns. Choice of antigens and the patterns of wells depend upon the resources available to the laboratory engaged in serological testing.

Polyene sensitivity during germination of conidia of Aspergillus fumigatus.

A system for the rapid and relatively synchromous germination of conidia from a clinical isolate of Aspergillus fumigatus is described. The polyene-mediated release of K plus from germinating conidia has been determined. Ungerminated conidia were insensitive to amphotericin B methyl ester (AME) at concentrations greater than 50 mug/ml, but rapidly became sensitive to 1 to 2 mug AME/ml during the intitial stages of germination. These findings have been correlated with minimum inhibitory concentration values obtained in studies of conidial germination and hyphal outgrowth using a variety of growth tests.

In vitro susceptibility of isolates of Aspergillus fumigatus and Sporothrix schenckii to amphotericin B.

The in vitro susceptibility of 21 isolates of Aspergillus fumigatus and 12 isolates of Sporothrix schenckii to amphotericin B was determined. The minimal inhibitory concentration (MIC) for the A. fumigatus isolates ranged from 0.14 to 0.6 mug of drug per ml. The mean MIC for the 21 isolates was 0.33 mug per ml. The MIC for the 12 S. schenckii isolates ranged from 0.68 to 2.12 mug of drug per ml, with a mean MIC of 1.38 mug per ml.