fungi identification a dichotomous key approach. budding cells few or no hyphae hyphae seen...
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Fungi Identificationa dichotomous key approach
budding cellsfew or no hyphae
hyphae seen
Microscopic appearance of colonies:
colonies black
colonieswhitecreampinkred
Macroscopic appearance of colonies:
Aureobasidium
Chapter 8Yeas
t
septate aseptate
Hyphal appearance:
Mucoraceous moulds
arthroconidia(other forms
absent)
Other forms(arthroconidia
absent)
Conidial appearance:
Chapter 3
present absent
Conidia formed in chains:
present absent
Conidial chains in branches:
CHAPTER 6
CHAPTER 7
chains formed singly
on sides of hyphae or on
short branches
chains formed in
succession at the same
point, aggregating in masses
Conidial chain arrangement:
CHAPTER 4, 5, 6
CHAPTER 8
fruiting bodies
present?
CHAPTER 10
Positive for dermatophyt
e
Negative for dermatophyt
e
ARTHROSPORIC MOULDS
colony dark brown
or blackcolony white
or cream
Colony appearance:
Neoscytalidium dimidiatum
ARTHROSPORIC MOULDS
Arthrospores regularly
alternating with empty
cells
Arthrospores not separated
by empty cells
Arthrospore arrangement:
ARTHROSPORIC MOULDS
Wider than 2 microns
Mostly 1 - 1.5 microns wide
Arthrospore Size:
Coccidioides spp
Malbranchea spp.
ARTHROSPORIC MOULDS
Colony with little aerial mycelium
Colony floccose
Colony morphology
Geotrichum spp OR
Trichosporon spp
ARTHROSPORIC MOULDS
Rapid growth (diameter
>20mm in 1 week)
Slow growth
Culture growth speed:
Onychocola canadensis
ARTHROSPORIC MOULDS
abundant, 4-8 microns wide,
rounded appearance
few, 2-5 microns wide,
flat-ended
Arthrospore numbers:
Basidiomycete moulds
Hyaline variant of Neoscytalidium
dimidiatum
ARTHROSPORIC MOULDS
Present Absent
Presence of blastoconidia:
Geotrichum spp
Trichosporon spp
DERMATOPHYTIC MOULDS
Macroconidia predominant
Neither macro nor
micro conidia present
Pattern of conidia:
Microconidia predominant
DERMATOPHYTIC MOULDS
Rough
Surface of macroconidia:
Smooth
DERMATOPHYTIC MOULDS
Present
Presence of terminal beak on macroconidia
Absent
Microsporum gypseum
Microsporum fulvum
DERMATOPHYTIC MOULDS
Large>50 microns
Size of Macroconidia
Smaller <50 microns
Microsporum equinum
Microsporum canis
DERMATOPHYTIC MOULDS
Khaki-brown to greenish-
yellowSome purple coloration
Colony colour:
White, cream or yellow
Epidermophyton floccosum
Trichophyton terrestre
Trichophyton ajelloi
Trichophyton rubrum
(granular form)
DERMATOPHYTIC MOULDS
floccose/velvety, white with red-brown reverse,
peg-like microconidia
Colony: OTHERWISE
Colony morphology
velvety/granular, cream with dark brown reverse,
round microconidia
Trichophyton rubrum
DERMATOPHYTIC MOULDS
Spiral hyphae, microconidia rare
(foot isolate)
Microconidia number:
brown veins on colony reverse, spiral hyphae, microconidia
common
Trichophyton interdigitale
Trichophyton mentagrophytes
DERMATOPHYTIC MOULDS
small and peg-like
larger, oval(colony with
brown reverse)
Microconidia shape
small, oval-round with a wide base
DERMATOPHYTIC MOULDS
flat, white, velvety,
bright yellow reverse
floccose, white,
reverse NOT yellow
Colony Morphology:
buff-cream, velvety, brown
reverse with yellow edge
Trichophyton erinacei
Trichophyton equinum
DERMATOPHYTIC MOULDS
Slow-growing(<10 mm/wk)
Rapid(20-30mm/wk)
Colony Growth Rate:
Intermediate (10-15mm/wk)
Trichophyton verrucosum
(sporulating variants)
Trichophyton rubrum(poorly-pigmented
variants)
Trichophyton interdigitale
(downy form)
DERMATOPHYTIC MOULDS
heaped, pink or yellow tinge,
reverse yellow, reflexive
branching at colony edge
(slow)
Colony Morphology
reverse brownish, broad-
based microconidia,
formed at end of hyphal side branches
Trichophyton soudanense
Microsporum persicolor
DERMATOPHYTIC MOULDS
granular/velvety, reddish colour, reverse dark-brown, clear white edge
Colony Morphology
granular/velvety, brown to cream,
reverse dark-brown with
colourless edge
Trichophyton rubrum
(granular form)
Microsporum tonsurans
DERMATOPHYTIC MOULDS
Moderately Rapid(>15mm/wk)
Growth Rate:
Slow (<15mm/wk)
DERMATOPHYTIC MOULDS
Densely floccose
Colony Morphology:
Loosely floccose or velvet
Trichophyton rubrum
DERMATOPHYTIC MOULDS
Reverse pale pinkish-brown,
pectinate hyphae seen
Colony Colour:
Reverse yellow
Microsporum audouinii
DERMATOPHYTIC MOULDS
Reverse intense orange-yellow,
mostly no aerial hyphae
Colony Colour:
Reverse clear-yellow, mostly
floccose
Trichophyton interdigitale
(nodular form)
Microsporum canis
DERMATOPHYTIC MOULDS
dark purple-brown,
little or no aerial growth
Colony Colour:
white, grey or cream,
floccose or folded
Trichophyton violaceum
DERMATOPHYTIC MOULDS
colony strongly folded
Colony Morphology:
colony almost microscopic,
floccose
Trichophyton verrucosum
DERMATOPHYTIC MOULDS
Nail-head hyphae and favic
chandeliers present, grows
without thiamine
Microscopic appearance:
Nail-head hyphae and favic
chandeliers absent, thiamine
dependent
Trichophyton concentricum
Trichophyton schoenleinii
Order onygenales
absent
Presence of conidia:
present
Paracoccidioides brasiliensis
Order onygenales
conidia large, spherical,
rough-walled or
tuberculate
Conidia morphology:
Not as described
Histoplasma capsulatum
Order onygenales
small <4 microns
long
Conidia size:
longer than 4 microns
Order onygenales
broad-based on acutely
angled conidiophores
Conidia arrangement:
very narrow based, on sides of
hyphae or on short stalks
Geomyces pannorum
Blastomyces dermatitidis
Order onygenales
cinnamon-brown in centre, some
conidia on swollen hyphal
cells
Colony morphology:
white to cream in centre, conidia NOT on swollen
hyphal cells
Myceliopthora thermophila
Chrysosporium keratinophilum
dematiaceous hyphomycetes
Single-celled conidia
Conidial forms:
Multi-celled conidia
dematiaceous hyphomycetes
mucoid, white or pale pink turning dark
later
Colony morphology:
floccose or velvety,
brown-olive colour
dematiaceous hyphomycetes
conidia produced in clusters on the sides of the hyphae
Conidia morphology:
conidia produced in
terminal rosettes on denticles
Aureobasidium pullulans
Sporothrix schenkii
dematiaceous hyphomycetes
conidia produced in
chains
Conidia morphology:
conidia NOT in chains
dematiaceous hyphomycetes
conidia chains long and rarely branching
Conidia chain length and form:
conidial chains short and heavily branched
dematiaceous hyphomycetes
no growth or very poor
growth at 37 C
Growth requirements:
good growth at 37 C and
40 C
Cladeophialophora carrionii
Cladeophialophora bantiana
dematiaceous hyphomycetes
conidia rough-walled
Conidial wall texture
conidia smooth-walled
Cladiosporium herbarum
dematiaceous hyphomycetes
Most conidia round
Conidial shape:
Most conidia oval or lemon
shaped
Cladosporium sphaerospermum
dematiaceous hyphomycetes
conidial chains very short and compact
Conidial chain length:
conidial chains longer,
more divergent
Fonsecaea pedrosi
Cladosporium cladosporioides
dematiaceous hyphomycetes
conidia elongate, less
than 2 microns wide
Conidia morphology:
conidia broadly oval, more than 2 microns wide
Rhinocladiella atrovirens
Rhinocladiella mackenziei
dematiaceous hyphomycetes
conidia all two-celled and thin-walled
Conidia cellularity:
conidia with more than two cells
Ochroconis gallopava
dematiaceous hyphomycetes
some conidia with oblique or
longitudinal septa in addition
to transverse septa
Conidia septa:
conidia with transverse septa only
dematiaceous hyphomycetes
conidia in chains, most often > 3,
most conidia with apical beak
Conidia morphology:
conidia formed singly or in
chains of 2-3, mostly without a
beak
Alternaria alternata
Ulocladium chartarum
dematiaceous hyphomycetes
Conidia symmetrical
Conidia morphology:
Conidia oval or
asymmetrical
Curvularia lunata
dematiaceous hyphomycetes
conidia oval with few
septa and hila not
protruding
Conidial septa and hila:
conidia oval with many septa and strongly
protruding hila
dematiaceous hyphomycetes
conidia mostly with five septa
Number of septa:
conidia mostly with three septa
Bipolaris hawaiiensis
Bipolaris australiensis
dematiaceous hyphomycetes
conidia widest near
the base
Conidia morphology:
conidia NOT widest near the
base, some worth projections on conidia walls
Exserohilum mcginisii
dematiaceous hyphomycetes
conidia with both the
basal septum and apical
septum dark
Conidia morphology:
conidia with basal septum
only darker than the others
Exserohilum longistratum
Exserohilum rostratum
moulds with chains of dry conidia arising from phialides
Present
Presence of vesicles at the tip of
conidiophore stalk
Absent
aspergillus species complexes
Some shade of green
Colony colour:
Not green
aspergillus species complexes
elongated vesicle
(>100 microns long)
Vesicle shape:
vesicles rounded
Aspergillus clavatus
aspergillus species complexes
colony uniformly
yellow-green, stalks rough
Colony morphology:
Colony dark green,
sometimes with yellow areas, stalks smooth
Aspergillus flavus
aspergillus species complexes
absent
Presence of metulae (cell layer between vesicle and spore-forming
phialides)
present
aspergillus species complexes
Over upper two-thirds of
small flattened vesicle
Distribution of phialides
Over entire surface of
large, round vesicle
Aspergillus fumigatus
Aspergillus glaucus
aspergillus species complexes
stalks pale brown, heads columnar in old cultures
Colony morphology
Stalks colourless,
heads globose or irregular
Aspergillus nidulans
Aspergillus versicolor
aspergillus species complexes
Stalks rough, colony
orange brown
Colony morphology
Stalks brown or yellow
Aspergillus ochraceus
Stalks colourless
aspergillus species complexes
dull grey to charcoal
Colony colour
yellow to buff
Aspergillus ustus
Aspergillus flavipes
aspergillus species complexes
black or dark brown
Colony colour:
cinnamon-brown to
sand-coloured
Aspergillus niger
white or pale cream
Aspergillus terreus
Aspergillus candidus
other chain-forming enteroblastic moulds
colony green
Colony colour:
colony not green
Penicillium spp
other chain-forming enteroblastic moulds
conidia large, round, with a
flat scar
Conidia morphology:
conidia small, oval, with a minute scar
Scopulariopsis brevicaulis
other chain-forming enteroblastic moulds
colony pale purple
Conidia colour:
colony greenish-buff
Purpureocillium lilacinum
Paecilomyces variotti
moulds with wet conidia adhering in masses
white, grey,
pink OR red colonies
Colony colour:
brown OR
black colonies
moulds with wet conidia adhering in masses
remain white or pink without brown
pigment
Colour of old colonies:
develop dark pigment
moulds with wet conidia adhering in masses
present
Presence of macroconidia:
absent (only unicellular
microconidia present)
moulds with wet conidia adhering in masses
macroconidia straight with round ends
Macroconidia morphology:
macroconidia curved with
pointed ends
Fusarium lichenicola
moulds with wet conidia adhering in masses
macroconidia mostly two-
celled
Macroconidia morphology:
macroconidia on
polyphialides
Fusarium dimerum
Fusarium semitectum
moulds with wet conidia adhering in masses
microconidia on short phialides
Microconidia arrangement:
microconidia on long
phialides
moulds with wet conidia adhering in masses
microconidia elongated,
some forming chains
Microconidia morphology:
microconidia ovoid to kidney-
shaped, not in chains
Fusarium proliferatum or
Fusarium verticilloides
Fusarium oxysporum
moulds with wet conidia adhering in masses
conidia mostly wider
than 2 microns
Conidia size:
conidia narrower
than 2 microns
Fusarium solani
Acremonium strictum
moulds with wet conidia adhering in masses
colonies mostly
glabrous(at least near the
edge)
Colony morphology:
colonies mostly
floccose
moulds with wet conidia adhering in masses
long and tapering
Phialide morphology:
reduced to short
outgrowths of hyphal cells
short annelids with swollen bases
Acremonium kiliense or
Phaeoacremonium parasiticum
Lecythophora mutabilis
Scedosporium prolificans
moulds with wet conidia adhering in masses
conidia large, 6 - 12
microns long
Conidia size:
conidia smaller, 3 - 7 microns long
Scedosporium apiospermum
Phaeoacremonium parasiticum
moulds with wet conidia adhering in masses
distinct collarettes
present
Presence of collarettes on
conidiogenous cells:
collarettes absent
moulds with wet conidia adhering in masses
minute and cylindrical
Collarette morphology:
flared or reflexed
cup-shaped or funnel-shaped
Phaeoacremonium parasiticum
Pleurostomophora richardsiae
Phialophora verrucosa
moulds with wet conidia adhering in masses
two-celled yeasts
abundant; large
annellidic pegs
Presence of two-celled yeasts:
two-celled yeasts absent, minute
annellidic pegs
Hortaea werneckii
moulds with wet conidia adhering in masses
branched conidiophores
of thick-walled
segments
Conidia arrangement:
conidia borne on sides of
hyphae, or on simple
branches
conidia borne on short
annelids with swollen bases
Exophalia spinifera
Scedosporium prolificans
moulds with wet conidia adhering in masses
grows at 40C; nitrate test negative (some conidia
formed without obvious annellidic
pegs)
Growth features:
no growth at 40C, nitrate
test negative (annellidic pegs
visible)
Exophalia dermatitidis
Exophalia jeanselmei
mucoraceous moulds
Yes
Sporulation on Sabouraud’s Dextrose Agar
No
mucoraceous moulds
colonies floccose,
rapid growth at 37C
Colony morphology and growth:
colonies floccose, no growth at
37C
colonies membranous
and waxy, slow growing
mucoraceous moulds
spores produced outside a vesicle
Spore formation:
spores produced inside a
sporangia
Cunninghamella bertholletiae
mucoraceous moulds
sporangia with funnel-
shaped bases
Sporangia morphology:
sporangial base
narrowing abruptly to a
stalk
Lichtheimia corymbifera
mucoraceous moulds
stalks with a few side branches
Stalk morphology:
stalks unbranched
mucoraceous moulds
one or two small
sporangia just under
main sporangia
Branching of sporangia
branches more widely
spaced, often curved
Rhizomucos pusillus
Mucor circinelloides
mucoraceous moulds
colony 3-5mm deep, sporangia
grey
Colony morphology:
colony filling the plate air
space, sporangia
black
Rhizomucos pusillus
mucoraceous moulds
stalks about 500 microns long, spores 4-6 microns
Stalk and spore morphology:
stalks over 1000 microns long, spores 6-8 microns
Rhizopus microsporus
Rhizopus arrhizus
mucoraceous moulds
sporangia black,
rhizoids prominent at base of stalk
Sporangia morphology and
Presence of Rhizoids:
sporangia pale or
brownish, rhizoids absent
Rhizopus stolonifer
mucoraceous moulds
colonies pale yellow
Colony colour
colonies pale brown,
some stalks with chlamydospores
Mucor hiemalis
Mucor racemosus
mucoraceous moulds
spores without conical papillae
Spore morphology:
spores with conical papillae
Basidiobolus ranarum
Conidiobolus coronatus
mucoraceous moulds
motile zoospores
produced in liquid culture
Nature of spores:
mucoraceous sporangia
produced on special media
Pythium spp.
mucoraceous moulds
sporangia on funnel-
shaped bases
Sporangia morphology:
sporangia with apical
tubular extensions
sporangia round,
rupturing without leaving a columella
Apophysomyces elegans
Saksenaea vasiformis
Mortierella wolfii
moulds that produce macroscopic fruiting bodies
and miscellaneous moulds
within 2 weeks
Production of fruiting bodies:
after 2 weeks fruiting bodies absent
moulds that produce macroscopic fruiting bodies
and miscellaneous moulds
pale-walled fruiting bodies
Fruiting body morphology:
dark-walled fruiting bodies
moulds that produce macroscopic fruiting bodies
and miscellaneous moulds
colonies white to buff
coloured
Colony colour:
colonies dark purple
Aphanoascus fulvescens
Monascus ruber
moulds that produce macroscopic fruiting bodies
and miscellaneous moulds
thick-walled ascocarps, covered in long brown
hyphae
Fruiting body morphology:
Pycnidia, with thin smooth
walls
Chaetomium spp.
Phoma herbarum
moulds that produce macroscopic fruiting bodies
and miscellaneous moulds
loose network of dark hyphae
Fruiting body morphology:
flattened, pale-coloured
with gillsblack, with a definite wall
Myxotrichum deflexum
Schizophyllum commune
moulds that produce macroscopic fruiting bodies
and miscellaneous moulds
thick-walled ascocarps, containing
asci
Fruiting body morphology:
Pycnidia, with thin smooth
walls
moulds that produce macroscopic fruiting bodies
and miscellaneous moulds
large, mostly five-celled
Ascospore morphology:
small, two-celled,
ascocarp wall of
interlocking plates
long, flexuous, with tapered ends
Leptosphaeria senegalensis
Neotestudina rosatii
Piedraia hortae
moulds that produce macroscopic fruiting bodies
and miscellaneous moulds
conidia large, two-celled
when mature
Conidia morphology:
conidia small, one-celled,
pycnidia with spines
Lasiodiplodia theobromae
Pyrenochaeta romeroi
moulds that produce macroscopic fruiting bodies
and miscellaneous moulds
colony flat or folded,
velvety, with diffusing brown
pigment
Colony morphology:
colony domed, densely floccose, without diffusing
pigment
Madurella mycetomatis
Madurella grisea group
identification of yeasts
minute colonies on
glucose peptone agar
Colony morphology:
pink or red colonies on
glucose peptone agar
white or cream
colonies on glucose
peptone agar
presumptive Malassezia
furfur
presumptive Rhodotorula spp
OR Sporobolomyces
spp
identification of yeasts
Germ Tube test:
positive negative
Candida albicansCandida
dubliniensisCandida africana
identification of yeasts
Presence of capsule:
present absent
presumptiveCryptococcus
spp.
identification of yeasts
Urease test:
positive negative
presumptiveCryptococcus spp.
OR Trichosporon sppOR Malassezia pachydermatis
identification of yeasts
Presence of chlamydospores
on cornmeal agar:
present negative
Candia albicansCandida
dubliniensis
identification of yeasts
Presence of arthrospores
on cornmeal agar:
present negative
identification of yeasts
Presence of budding cells
on cornmeal agar:
presentnegative
dichotomously branching
hyphae present
presumptive Trichosporon spp
OR Saprochaete capitata
Geotrichum candidum
identification of yeasts
Pseudohyphae present:
present negative
presumptive
Candida spp
dy/dx:
Macroscopic Features
Neoscatylidium dimidiatum
Microscopic Features
clinicalsignificance
skin and nail infections amongimmigrants from the tropics and sub-tropics.Not contagious (unlike dermatophytosis)