Species

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Aspergillus flavus High power image (1000x) of Aspergillus flavus in hand tissue from a patient at Stanford University Medical Center (GMS stain).
Aspergillus flavus High power image (1000x) of Aspergillus flavus in hand tissue from a patient at Stanford University Medical Center (GMS stain).

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.

Aspergillus flavus Image of Aspergillus flavus hyphae (400x) in hand tissue of same patient stained with Haemotoxylin eosin.
Aspergillus flavus Image of Aspergillus flavus hyphae (400x) in hand tissue of same patient stained with Haemotoxylin eosin.

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.

Aspergillus flavus Aspergillus flavus
Aspergillus flavus Aspergillus flavus

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.

Aspergillus flavus Macroscopic colony appearance
Aspergillus flavus Macroscopic colony appearance

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.

Aspergillus flavus Conidia
Aspergillus flavus Sporing
Aspergillus flavus
Aspergillus flavus Conidiophore
Aspergillus flavus Conidiophore
Aspergillus flavus
Aspergillus flavus

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.

Aspergillus flavus cultures grown from BAL fluid showing formation of sclerotia.
Aspergillus flavus cultures grown from BAL fluid showing formation of sclerotia. <p>These colonies were isolated from a BAL, (also with bacterial qrowth of S.aureus and S.maltophilia) from a patient with a VAP (undergoing corticosteroid treatment). The growth medium used is sabouraud dextrose agar , incubated at 37° C The identification is made by microscopic/macroscopic observation criteria.</p> <p style="font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 12px; line-height: 1.5; color: rgb(0, 0, 0);">Colonies on&nbsp;CYA&nbsp;60-70 mm&nbsp;diam, plane, sparse to moderately dense,&nbsp;velutinous&nbsp;in marginal areas at least, often&nbsp;floccose&nbsp;centrally, sometimes deeply so; mycelium only conspicuous in&nbsp;floccose&nbsp;areas, white;&nbsp;conidial&nbsp;heads usually borne uniformly over the whole colony, but sparse or absent in areas of&nbsp;floccose&nbsp;growth or&nbsp;sclerotial&nbsp;production, characteristically&nbsp;Greyish&nbsp;Green to Olive Yellow (1-2B-E5-7), but sometimes pure Yellow (2-3A7-8), becoming greenish in age;&nbsp;sclerotia&nbsp;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&nbsp;conidial&nbsp;production;&nbsp;exudate&nbsp;sometimes produced, clear, or reddish brown near&nbsp;sclerotia; reverse&nbsp;uncoloured&nbsp;or brown to reddish brown beneath&nbsp;sclerotia. Colonies on MEA 50-70 mm&nbsp;diam, similar to those on&nbsp;CYA&nbsp;although usually less dense. Colonies on&nbsp;G25N&nbsp;25-40 mm&nbsp;diam, similar to those on&nbsp;CYA&nbsp;or more deeply&nbsp;floccose&nbsp;and with little&nbsp;conidial&nbsp;production, reverse pale to orange or salmon. No growth at 5°C. At 37°C, colonies usually 55-65 mm&nbsp;diam, similar to those on&nbsp;CYA&nbsp;at 25°C, but more&nbsp;velutinous, with olive&nbsp;conidia, and sometimes with more abundant&nbsp;sclerotia.</p> <p style="font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 12px; line-height: 1.5; color: rgb(0, 0, 0);">Sclerotia&nbsp;produced by some isolates, at first white, rapidly becoming hard and reddish brown to black, spherical, usually 400- 800 µm&nbsp;diam.&nbsp;Teleomorph&nbsp;not known.&nbsp;Conidiophores&nbsp;borne from subsurface or surface&nbsp;hyphae,&nbsp;stipes&nbsp;400 µm to 1 mm or more long,&nbsp;colourless&nbsp;or pale brown, rough walled; vesicles spherical, 20-45 µm&nbsp;diam, fertile over three quarters of the surface, typically bearing both&nbsp;metulae&nbsp;and&nbsp;phialides, but in some isolates a proportion or even a majority of heads with&nbsp;phialides&nbsp;alone;&nbsp;metulae&nbsp;and&nbsp;phialides&nbsp;of similar size, 7-10 µm long;&nbsp;conidia&nbsp;spherical to&nbsp;subspheroidal, usually 3.5-5.0 µm&nbsp;diam, with relatively thin walls, finely roughened or, rarely, smooth.</p> <h4 style="line-height: normal; font-family: Verdana, Arial, Helvetica, sans-serif; color: rgb(0, 0, 0);">Distinctive features</h4> <p style="font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 12px; line-height: 1.5; color: rgb(0, 0, 0);"><i>Aspergillus&nbsp;flavus</i>&nbsp;is distinguished by rapid growth at both 25°C and 37°C, and a bright yellow green (or less commonly yellow)&nbsp;conidial&nbsp;colour.&nbsp;<i>A.&nbsp;flavus</i>&nbsp;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.</p>
Aspergillus flavus Microscopic morphology of A. flavus. Conidial heads are radiate, splitting to form loose columns, biseriate but having some heads with phialides borne directly on the vesicle.
Aspergillus flavus Microscopic morphology of A. flavus. Conidial heads are radiate, splitting to form loose columns, biseriate but having some heads with phialides borne directly on the vesicle.

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.

Aspergillus flavus
Aspergillus flavus

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.

Aspergillus flavus cultures grown from BAL fluid showing formation of sclerotia.
Aspergillus flavus cultures grown from BAL fluid showing formation of sclerotia. <p>These colonies were isolated from a BAL, (also with bacterial qrowth of S.aureus and S.maltophilia) from a patient with a VAP (undergoing corticosteroid treatment). The growth medium used is sabouraud dextrose agar , incubated at 37° C The identification is made by microscopic/macroscopic observation criteria.</p> <p style="font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 12px; line-height: 1.5; color: rgb(0, 0, 0);">Colonies on&nbsp;CYA&nbsp;60-70 mm&nbsp;diam, plane, sparse to moderately dense,&nbsp;velutinous&nbsp;in marginal areas at least, often&nbsp;floccose&nbsp;centrally, sometimes deeply so; mycelium only conspicuous in&nbsp;floccose&nbsp;areas, white;&nbsp;conidial&nbsp;heads usually borne uniformly over the whole colony, but sparse or absent in areas of&nbsp;floccose&nbsp;growth or&nbsp;sclerotial&nbsp;production, characteristically&nbsp;Greyish&nbsp;Green to Olive Yellow (1-2B-E5-7), but sometimes pure Yellow (2-3A7-8), becoming greenish in age;&nbsp;sclerotia&nbsp;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&nbsp;conidial&nbsp;production;&nbsp;exudate&nbsp;sometimes produced, clear, or reddish brown near&nbsp;sclerotia; reverse&nbsp;uncoloured&nbsp;or brown to reddish brown beneath&nbsp;sclerotia. Colonies on MEA 50-70 mm&nbsp;diam, similar to those on&nbsp;CYA&nbsp;although usually less dense. Colonies on&nbsp;G25N&nbsp;25-40 mm&nbsp;diam, similar to those on&nbsp;CYA&nbsp;or more deeply&nbsp;floccose&nbsp;and with little&nbsp;conidial&nbsp;production, reverse pale to orange or salmon. No growth at 5°C. At 37°C, colonies usually 55-65 mm&nbsp;diam, similar to those on&nbsp;CYA&nbsp;at 25°C, but more&nbsp;velutinous, with olive&nbsp;conidia, and sometimes with more abundant&nbsp;sclerotia.</p> <p style="font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 12px; line-height: 1.5; color: rgb(0, 0, 0);">Sclerotia&nbsp;produced by some isolates, at first white, rapidly becoming hard and reddish brown to black, spherical, usually 400- 800 µm&nbsp;diam.&nbsp;Teleomorph&nbsp;not known.&nbsp;Conidiophores&nbsp;borne from subsurface or surface&nbsp;hyphae,&nbsp;stipes&nbsp;400 µm to 1 mm or more long,&nbsp;colourless&nbsp;or pale brown, rough walled; vesicles spherical, 20-45 µm&nbsp;diam, fertile over three quarters of the surface, typically bearing both&nbsp;metulae&nbsp;and&nbsp;phialides, but in some isolates a proportion or even a majority of heads with&nbsp;phialides&nbsp;alone;&nbsp;metulae&nbsp;and&nbsp;phialides&nbsp;of similar size, 7-10 µm long;&nbsp;conidia&nbsp;spherical to&nbsp;subspheroidal, usually 3.5-5.0 µm&nbsp;diam, with relatively thin walls, finely roughened or, rarely, smooth.</p> <h4 style="line-height: normal; font-family: Verdana, Arial, Helvetica, sans-serif; color: rgb(0, 0, 0);">Distinctive features</h4> <p style="font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 12px; line-height: 1.5; color: rgb(0, 0, 0);"><i>Aspergillus&nbsp;flavus</i>&nbsp;is distinguished by rapid growth at both 25°C and 37°C, and a bright yellow green (or less commonly yellow)&nbsp;conidial&nbsp;colour.&nbsp;<i>A.&nbsp;flavus</i>&nbsp;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.</p>
Aspergillus fumigatus These colonies were isolated from a BAL, (also with bacterial qrowth of S.aureus and S.maltophilia) from a patient with a VAP (undergoing corticosteroid treatment). The growth medium used is sabouraud dextrose agar , incubated at 37° C The read more...
Aspergillus fumigatus These colonies were isolated from a BAL, (also with bacterial qrowth of S.aureus and S.maltophilia) from a patient with a VAP (undergoing corticosteroid treatment). The growth medium used is sabouraud dextrose agar , incubated at 37° C The read more...
Aspergillus flavus cultures grown from BAL fluid showing formation of sclerotia.
Aspergillus flavus cultures grown from BAL fluid showing formation of sclerotia. <p>These colonies were isolated from a BAL, (also with bacterial qrowth of S.aureus and S.maltophilia) from a patient with a VAP (undergoing corticosteroid treatment). The growth medium used is sabouraud dextrose agar , incubated at 37° C The identification is made by microscopic/macroscopic observation criteria.</p> <p style="font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 12px; line-height: 1.5; color: rgb(0, 0, 0);">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.</p> <p style="font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 12px; line-height: 1.5; color: rgb(0, 0, 0);">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.</p> <h4 style="font-family: Verdana, Arial, Helvetica, sans-serif; color: rgb(0, 0, 0); line-height: normal;">Distinctive features</h4> <p style="font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 12px; line-height: 1.5; color: rgb(0, 0, 0);"><i>Aspergillus flavus</i>&nbsp;is distinguished by rapid growth at both 25°C and 37°C, and a bright yellow green (or less commonly yellow) conidial colour.&nbsp;<i>A. flavus</i>&nbsp;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.</p>

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