fungi identification a dichotomous key approach. budding cells few or no hyphae hyphae seen...

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


Rough

Surface of macroconidia:

Smooth


Present

Presence of terminal beak on macroconidia

Absent

Microsporum gypseum

Microsporum fulvum


Large>50 microns

Size of Macroconidia

Smaller <50 microns

Microsporum equinum

Microsporum canis


Khaki-brown to greenish-

yellowSome purple coloration

Colony colour:

White, cream or yellow

Epidermophyton floccosum

Trichophyton terrestre

Trichophyton ajelloi

Trichophyton rubrum

(granular form)


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


Spiral hyphae, microconidia rare

(foot isolate)

Microconidia number:

brown veins on colony reverse, spiral hyphae, microconidia

common

Trichophyton interdigitale

Trichophyton mentagrophytes


small and peg-like

larger, oval(colony with

brown reverse)

Microconidia shape

small, oval-round with a wide base


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


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)


(downy form)


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


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


Moderately Rapid(>15mm/wk)

Growth Rate:

Slow (<15mm/wk)


Densely floccose

Colony Morphology:

Loosely floccose or velvet

Trichophyton rubrum


Reverse pale pinkish-brown,

pectinate hyphae seen

Colony Colour:

Reverse yellow

Microsporum audouinii


Reverse intense orange-yellow,

mostly no aerial hyphae

Colony Colour:

Reverse clear-yellow, mostly

floccose


(nodular form)

Microsporum canis


dark purple-brown,

little or no aerial growth

Colony Colour:

white, grey or cream,

floccose or folded

Trichophyton violaceum


colony strongly folded

Colony Morphology:

colony almost microscopic,

floccose

Trichophyton verrucosum


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


mucoid, white or pale pink turning dark

later

Colony morphology:

floccose or velvety,

brown-olive colour


conidia produced in clusters on the sides of the hyphae

Conidia morphology:

conidia produced in

terminal rosettes on denticles

Aureobasidium pullulans

Sporothrix schenkii


conidia produced in

chains

Conidia morphology:

conidia NOT in chains


conidia chains long and rarely branching

Conidia chain length and form:

conidial chains short and heavily branched


no growth or very poor

growth at 37 C

Growth requirements:

good growth at 37 C and

40 C

Cladeophialophora carrionii

Cladeophialophora bantiana


conidia rough-walled

Conidial wall texture

conidia smooth-walled

Cladiosporium herbarum


Most conidia round

Conidial shape:

Most conidia oval or lemon

shaped

Cladosporium sphaerospermum


conidial chains very short and compact

Conidial chain length:

conidial chains longer,

more divergent

Fonsecaea pedrosi

Cladosporium cladosporioides


conidia elongate, less

than 2 microns wide

Conidia morphology:

conidia broadly oval, more than 2 microns wide

Rhinocladiella atrovirens

Rhinocladiella mackenziei


conidia all two-celled and thin-walled

Conidia cellularity:

conidia with more than two cells

Ochroconis gallopava


some conidia with oblique or

longitudinal septa in addition

to transverse septa

Conidia septa:

conidia with transverse septa only


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


Conidia symmetrical

Conidia morphology:

Conidia oval or

asymmetrical

Curvularia lunata


conidia oval with few

septa and hila not

protruding

Conidial septa and hila:

conidia oval with many septa and strongly

protruding hila


conidia mostly with five septa

Number of septa:

conidia mostly with three septa

Bipolaris hawaiiensis

Bipolaris australiensis


conidia widest near

the base

Conidia morphology:

conidia NOT widest near the

base, some worth projections on conidia walls

Exserohilum mcginisii


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


elongated vesicle

(>100 microns long)

Vesicle shape:

vesicles rounded

Aspergillus clavatus


colony uniformly

yellow-green, stalks rough

Colony morphology:

Colony dark green,

sometimes with yellow areas, stalks smooth

Aspergillus flavus


absent

Presence of metulae (cell layer between vesicle and spore-forming

phialides)

present


Over upper two-thirds of

small flattened vesicle

Distribution of phialides

Over entire surface of

large, round vesicle

Aspergillus fumigatus

Aspergillus glaucus


stalks pale brown, heads columnar in old cultures

Colony morphology

Stalks colourless,

heads globose or irregular

Aspergillus nidulans

Aspergillus versicolor


Stalks rough, colony

orange brown

Colony morphology

Stalks brown or yellow

Aspergillus ochraceus

Stalks colourless


dull grey to charcoal

Colony colour

yellow to buff

Aspergillus ustus

Aspergillus flavipes


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


conidia large, round, with a

flat scar

Conidia morphology:

conidia small, oval, with a minute scar

Scopulariopsis brevicaulis


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


remain white or pink without brown

pigment

Colour of old colonies:

develop dark pigment


present

Presence of macroconidia:

absent (only unicellular

microconidia present)


macroconidia straight with round ends

Macroconidia morphology:

macroconidia curved with

pointed ends

Fusarium lichenicola


macroconidia mostly two-

celled

Macroconidia morphology:

macroconidia on

polyphialides

Fusarium dimerum

Fusarium semitectum


microconidia on short phialides

Microconidia arrangement:

microconidia on long

phialides


microconidia elongated,

some forming chains

Microconidia morphology:

microconidia ovoid to kidney-

shaped, not in chains

Fusarium proliferatum or

Fusarium verticilloides

Fusarium oxysporum


conidia mostly wider

than 2 microns

Conidia size:

conidia narrower

than 2 microns

Fusarium solani

Acremonium strictum


colonies mostly

glabrous(at least near the

edge)

Colony morphology:

colonies mostly

floccose


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


conidia large, 6 - 12

microns long

Conidia size:

conidia smaller, 3 - 7 microns long

Scedosporium apiospermum



distinct collarettes

present

Presence of collarettes on

conidiogenous cells:

collarettes absent


minute and cylindrical

Collarette morphology:

flared or reflexed

cup-shaped or funnel-shaped


Pleurostomophora richardsiae

Phialophora verrucosa


two-celled yeasts

abundant; large

annellidic pegs

Presence of two-celled yeasts:

two-celled yeasts absent, minute

annellidic pegs

Hortaea werneckii


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


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



pale-walled fruiting bodies

Fruiting body morphology:

dark-walled fruiting bodies



colonies white to buff

coloured

Colony colour:

colonies dark purple

Aphanoascus fulvescens

Monascus ruber



thick-walled ascocarps, covered in long brown

hyphae


Pycnidia, with thin smooth

walls

Chaetomium spp.

Phoma herbarum



loose network of dark hyphae


flattened, pale-coloured

with gillsblack, with a definite wall

Myxotrichum deflexum

Schizophyllum commune



thick-walled ascocarps, containing

asci


Pycnidia, with thin smooth

walls



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



conidia large, two-celled

when mature

Conidia morphology:

conidia small, one-celled,

pycnidia with spines

Lasiodiplodia theobromae

Pyrenochaeta romeroi



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


Germ Tube test:

positive negative

Candida albicansCandida

dubliniensisCandida africana


Presence of capsule:

present absent

presumptiveCryptococcus

spp.


Urease test:

positive negative

presumptiveCryptococcus spp.

OR Trichosporon sppOR Malassezia pachydermatis


Presence of chlamydospores

on cornmeal agar:

present negative

Candia albicansCandida

dubliniensis


Presence of arthrospores

on cornmeal agar:

present negative


Presence of budding cells

on cornmeal agar:

presentnegative

dichotomously branching

hyphae present

presumptive Trichosporon spp

OR Saprochaete capitata

Geotrichum candidum


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)

fungi identification a dichotomous key approach. budding cells few or no hyphae hyphae seen...

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