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)

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