Date: 26 November 2013
Aspergillus flavus
Copyright:
© Fungal Research Trust
Notes:
Colonies on CYA 60-70 mm diam, plane, sparse to moderately dense, velutinous in marginal areas at least, often floccose centrally, sometimes deeply so; mycelium only conspicuous in floccose areas, white; conidial heads usually borne uniformly over the whole colony, but sparse or absent in areas of floccose growth or sclerotial production, characteristically Greyish Green to Olive Yellow (1-2B-E5-7), but sometimes pure Yellow (2-3A7-8), becoming greenish in age; sclerotia produced by about 50% of isolates, at first white, becoming deep reddish brown, density varying from inconspicuous to dominating colony appearance and almost entirely suppressing conidial production; exudate sometimes produced, clear, or reddish brown near sclerotia; reverse uncoloured or brown to reddish brown beneath sclerotia. Colonies on MEA 50-70 mm diam, similar to those on CYA although usually less dense. Colonies on G25N 25-40 mm diam, similar to those on CYA or more deeply floccose and with little conidial production, reverse pale to orange or salmon. No growth at 5°C. At 37°C, colonies usually 55-65 mm diam, similar to those on CYA at 25°C, but more velutinous, with olive conidia, and sometimes with more abundant sclerotia.
Sclerotia produced by some isolates, at first white, rapidly becoming hard and reddish brown to black, spherical, usually 400- 800 µm diam. Teleomorph not known. Conidiophores borne from subsurface or surface hyphae, stipes 400 µm to 1 mm or more long, colourless or pale brown, rough walled; vesicles spherical, 20-45 µm diam, fertile over three quarters of the surface, typically bearing both metulae and phialides, but in some isolates a proportion or even a majority of heads with phialides alone; metulae and phialides of similar size, 7-10 µm long; conidia spherical to subspheroidal, usually 3.5-5.0 µm diam, with relatively thin walls, finely roughened or, rarely, smooth.
Distinctive features
Aspergillus flavus is distinguished by rapid growth at both 25°C and 37°C, and a bright yellow green (or less commonly yellow) conidial colour. A. flavus produces conidia which are rather variable in shape and size, have relatively thin walls, and range from smooth to moderately rough, the majority being finely rough.
Images library
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Patient MB X rays and CT scans. Chronic calcified maxillary sinusitis, patient had a palate defect.A. fumigatus cultured.
Images A&B Plain X rays antero-posterior and lateral, pre-operatively of Pt MB aged 76 who presented with unilateral nasal stuffiness and difficulty getting dentures fitted. She had hda these symptoms for many years. A large irregular calcified mass can be seen replacing the right maxillary sinus.
Images C D & E Coronal CT scan images of Pt MB showing a completely obstructed nasal cavity bilaterally and loss of internal nasal architecture. On the right side is large lamellar calcified lesion embedded in the extensive inflammatory material. Loss of bony margins is seen in numerous locations. This material was all removed surgically and showed mostly necrotic debris with Charcot-Leyden crystals and a few eosinophils and degenerate fungal hyphae. Aspergillus fumigatus was cultured from the material, especially infero-laterally on the right.
Image F Photograph through the mouth post-operatively showing the palate and a large defect in its right side. Through the defect can be seen the interior of the right maxillary sinus and nasal cavity with the inferior turbinate just visible.
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Aspergillus keratitis. Severe aspergillus infection with large area of corneal ulceration and deep stromal involvement
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Sequence of images showing ocular surface change which unusually predisposed to severe fusarium keratitis in an elderly woman. Successful treatment involved full thickness corneal transplantation shown 2 weeks and then 2 years after surgery.
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Sequence of images showing ocular surface change which unusually predisposed to severe fusarium keratitis in an elderly woman. Successful treatment involved full thickness corneal transplantation shown 2 weeks and then 2 years after surgery.
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Sequence of images showing ocular surface change which unusually predisposed to severe fusarium keratitis in an elderly woman. Successful treatment involved full thickness corneal transplantation shown 2 weeks and then 2 years after surgery.
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Sequence of images showing ocular surface change which unusually predisposed to severe fusarium keratitis in an elderly woman. Successful treatment involved full thickness corneal transplantation shown 2 weeks and then 2 years after surgery
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Aspergillus keratitis. Shrunken eye as a consequence of this infection
