a dichotomous key approach Fungi Identification a dichotomous key approach

Microscopic appearance of colonies: budding cells few or no hyphae hyphae seen

Macroscopic appearance of colonies: colonies black colonies white cream pink red Aureobasidium Chapter 8 Yeast

Hyphal appearance: septate aseptate Mucoraceous moulds

(arthroconidia absent) Conidial appearance: arthroconidia (other forms absent) Other forms (arthroconidia absent) Chapter 3

Conidia formed in chains: present absent

Conidial chains in branches: present absent CHAPTER 6 CHAPTER 7

Conidial chain arrangement: Positive for dermatophyte chains formed singly on sides of hyphae or on short branches Negative for dermatophyte chains formed in succession at the same point, aggregating in masses fruiting bodies present? CHAPTER 4, 5, 6 CHAPTER 8 CHAPTER 10

Neoscytalidium dimidiatum ARTHROSPORIC MOULDS Colony appearance: colony dark brown or black colony white or cream Neoscytalidium dimidiatum

Arthrospore arrangement: ARTHROSPORIC MOULDS Arthrospore arrangement: Arthrospores regularly alternating with empty cells Arthrospores not separated by empty cells

ARTHROSPORIC MOULDS Arthrospore Size: Wider than 2 microns Mostly 1 - 1.5 microns wide Coccidioides spp Malbranchea spp.

Colony with little aerial mycelium ARTHROSPORIC MOULDS Colony morphology Colony with little aerial mycelium Colony floccose Geotrichum spp OR Trichosporon spp

ARTHROSPORIC MOULDS Culture growth speed: Rapid growth (diameter >20mm in 1 week) Slow growth Onychocola canadensis

ARTHROSPORIC MOULDS Arthrospore numbers: abundant, 4-8 microns wide, rounded appearance few, 2-5 microns wide, flat-ended Hyaline variant of Neoscytalidium dimidiatum Basidiomycete moulds

Presence of blastoconidia: ARTHROSPORIC MOULDS Presence of blastoconidia: Present Absent Trichosporon spp Geotrichum spp

DERMATOPHYTIC MOULDS Pattern of conidia: Macroconidia predominant Microconidia predominant Neither macro nor micro conidia present

Surface of macroconidia: DERMATOPHYTIC MOULDS Surface of macroconidia: Rough Smooth

Presence of terminal beak on macroconidia DERMATOPHYTIC MOULDS Presence of terminal beak on macroconidia Present Absent Microsporum gypseum Microsporum fulvum

DERMATOPHYTIC MOULDS Size of Macroconidia Large >50 microns Smaller Microsporum canis Microsporum equinum

DERMATOPHYTIC MOULDS Colony colour: Khaki-brown to greenish-yellow White, cream or yellow Some purple coloration Trichophyton terrestre Trichophyton ajelloi Trichophyton rubrum (granular form) Epidermophyton floccosum

DERMATOPHYTIC MOULDS Colony morphology Colony: OTHERWISE floccose/velvety, white with red-brown reverse, peg-like microconidia velvety/granular, cream with dark brown reverse, round microconidia Colony: OTHERWISE Trichophyton rubrum

DERMATOPHYTIC MOULDS Microconidia number: Spiral hyphae, microconidia rare (foot isolate) brown veins on colony reverse, spiral hyphae, microconidia common Trichophyton interdigitale Trichophyton mentagrophytes

DERMATOPHYTIC MOULDS Microconidia shape small and peg-like small, oval-round with a wide base larger, oval (colony with brown reverse)

DERMATOPHYTIC MOULDS Colony Morphology: flat, white, velvety, bright yellow reverse buff-cream, velvety, brown reverse with yellow edge floccose, white, reverse NOT yellow Trichophyton erinacei Trichophyton equinum

DERMATOPHYTIC MOULDS Colony Growth Rate: Slow-growing Intermediate (<10 mm/wk) Intermediate (10-15mm/wk) Rapid (20-30mm/wk) Trichophyton verrucosum (sporulating variants) Trichophyton rubrum (poorly-pigmented variants) Trichophyton interdigitale (downy form)

DERMATOPHYTIC MOULDS Colony Morphology heaped, pink or yellow tinge, reverse yellow, reflexive branching at colony edge (slow) reverse brownish, broad-based microconidia, formed at end of hyphal side branches Trichophyton soudanense Microsporum persicolor

DERMATOPHYTIC MOULDS Colony Morphology granular/velvety, reddish colour, reverse dark-brown, clear white edge granular/velvety, brown to cream, reverse dark-brown with colourless edge Trichophyton rubrum (granular form) Microsporum tonsurans

DERMATOPHYTIC MOULDS Growth Rate: Moderately Rapid (>15mm/wk) Slow (<15mm/wk)

Loosely floccose or velvet DERMATOPHYTIC MOULDS Colony Morphology: Densely floccose Loosely floccose or velvet Trichophyton rubrum

DERMATOPHYTIC MOULDS Colony Colour: Reverse pale pinkish-brown, pectinate hyphae seen Reverse yellow Microsporum audouinii

DERMATOPHYTIC MOULDS Colony Colour: Reverse intense orange-yellow, mostly no aerial hyphae Reverse clear-yellow, mostly floccose Trichophyton interdigitale (nodular form) Microsporum canis

DERMATOPHYTIC MOULDS Colony Colour: dark purple-brown, little or no aerial growth white, grey or cream, floccose or folded Trichophyton violaceum

DERMATOPHYTIC MOULDS Colony Morphology: colony strongly folded colony almost microscopic, floccose Trichophyton verrucosum

Microscopic appearance: DERMATOPHYTIC MOULDS Microscopic appearance: Nail-head hyphae and favic chandeliers present, grows without thiamine Nail-head hyphae and favic chandeliers absent, thiamine dependent Trichophyton schoenleinii Trichophyton concentricum

Paracoccidioides brasiliensis Order onygenales Presence of conidia: absent present Paracoccidioides brasiliensis

Order onygenales Conidia morphology: conidia large, spherical, rough-walled or tuberculate Not as described Histoplasma capsulatum

Order onygenales Conidia size: small <4 microns long longer than

Order onygenales Conidia arrangement: broad-based on acutely angled conidiophores very narrow based, on sides of hyphae or on short stalks Geomyces pannorum Blastomyces dermatitidis

Order onygenales Colony morphology: cinnamon-brown in centre, some conidia on swollen hyphal cells white to cream in centre, conidia NOT on swollen hyphal cells Myceliopthora thermophila Chrysosporium keratinophilum

dematiaceous hyphomycetes Conidial forms: Single-celled conidia Multi-celled conidia

dematiaceous hyphomycetes Colony morphology: mucoid, white or pale pink turning dark later floccose or velvety, brown-olive colour

dematiaceous hyphomycetes Conidia morphology: conidia produced in clusters on the sides of the hyphae conidia produced in terminal rosettes on denticles Aureobasidium pullulans Sporothrix schenkii

dematiaceous hyphomycetes Conidia morphology: conidia produced in chains conidia NOT in chains

dematiaceous hyphomycetes Conidia chain length and form: conidia chains long and rarely branching conidial chains short and heavily branched

dematiaceous hyphomycetes Growth requirements: no growth or very poor growth at 37 C good growth at 37 C and 40 C Cladeophialophora carrionii Cladeophialophora bantiana

dematiaceous hyphomycetes Conidial wall texture conidia rough-walled conidia smooth-walled Cladiosporium herbarum

dematiaceous hyphomycetes Conidial shape: Most conidia round Most conidia oval or lemon shaped Cladosporium sphaerospermum

dematiaceous hyphomycetes Conidial chain length: conidial chains very short and compact conidial chains longer, more divergent Fonsecaea pedrosi Cladosporium cladosporioides

dematiaceous hyphomycetes Conidia morphology: conidia elongate, less than 2 microns wide conidia broadly oval, more than 2 microns wide Rhinocladiella atrovirens Rhinocladiella mackenziei

dematiaceous hyphomycetes Conidia cellularity: conidia all two-celled and thin-walled conidia with more than two cells Ochroconis gallopava

dematiaceous hyphomycetes Conidia septa: some conidia with oblique or longitudinal septa in addition to transverse septa conidia with transverse septa only

dematiaceous hyphomycetes Conidia morphology: conidia in chains, most often > 3, most conidia with apical beak conidia formed singly or in chains of 2-3, mostly without a beak Alternaria alternata Ulocladium chartarum

dematiaceous hyphomycetes Conidia morphology: Conidia oval or asymmetrical Conidia symmetrical Curvularia lunata

dematiaceous hyphomycetes Conidial septa and hila: conidia oval with many septa and strongly protruding hila conidia oval with few septa and hila not protruding

dematiaceous hyphomycetes Number of septa: conidia mostly with three septa conidia mostly with five septa Bipolaris hawaiiensis Bipolaris australiensis

dematiaceous hyphomycetes Conidia morphology: conidia NOT widest near the base, some worth projections on conidia walls conidia widest near the base Exserohilum mcginisii

dematiaceous hyphomycetes Conidia morphology: conidia with basal septum only darker than the others conidia with both the basal septum and apical septum dark Exserohilum rostratum Exserohilum longistratum

moulds with chains of dry conidia arising from phialides Presence of vesicles at the tip of conidiophore stalk Absent Present

aspergillus species complexes Colony colour: Not green Some shade of green

aspergillus species complexes Vesicle shape: vesicles rounded elongated vesicle (>100 microns long) Aspergillus clavatus

aspergillus species complexes Colony morphology: Colony dark green, sometimes with yellow areas, stalks smooth colony uniformly yellow-green, stalks rough Aspergillus flavus

aspergillus species complexes Presence of metulae (cell layer between vesicle and spore-forming phialides) present absent

aspergillus species complexes Distribution of phialides Over entire surface of large, round vesicle Over upper two-thirds of small flattened vesicle Aspergillus fumigatus Aspergillus glaucus

aspergillus species complexes Colony morphology Stalks colourless, heads globose or irregular stalks pale brown, heads columnar in old cultures Aspergillus nidulans Aspergillus versicolor

aspergillus species complexes Colony morphology Stalks rough, colony orange brown Stalks brown or yellow Stalks colourless Aspergillus ochraceus

aspergillus species complexes Colony colour yellow to buff dull grey to charcoal Aspergillus ustus Aspergillus flavipes

aspergillus species complexes Colony colour: black or dark brown cinnamon-brown to sand-coloured white or pale cream Aspergillus niger Aspergillus terreus Aspergillus candidus

other chain-forming enteroblastic moulds Colony colour: colony green colony not green Penicillium spp

other chain-forming enteroblastic moulds Conidia morphology: conidia large, round, with a flat scar conidia small, oval, with a minute scar Scopulariopsis brevicaulis

other chain-forming enteroblastic moulds Conidia colour: colony pale purple colony greenish-buff Purpureocillium lilacinum Paecilomyces variotti

moulds with wet conidia adhering in masses Colony colour: white, grey, pink OR red colonies brown OR black colonies

moulds with wet conidia adhering in masses Colour of old colonies: remain white or pink without brown pigment develop dark pigment

moulds with wet conidia adhering in masses Presence of macroconidia: present absent (only unicellular microconidia present)

moulds with wet conidia adhering in masses Macroconidia morphology: macroconidia straight with round ends macroconidia curved with pointed ends Fusarium lichenicola

moulds with wet conidia adhering in masses Macroconidia morphology: macroconidia mostly two-celled macroconidia on polyphialides Fusarium dimerum Fusarium semitectum

moulds with wet conidia adhering in masses Microconidia arrangement: microconidia on short phialides microconidia on long phialides

moulds with wet conidia adhering in masses Microconidia morphology: microconidia elongated, some forming chains microconidia ovoid to kidney-shaped, not in chains Fusarium proliferatum or Fusarium verticilloides Fusarium oxysporum

moulds with wet conidia adhering in masses Conidia size: conidia mostly wider than 2 microns conidia narrower than 2 microns Fusarium solani Acremonium strictum

moulds with wet conidia adhering in masses Colony morphology: colonies mostly glabrous (at least near the edge) colonies mostly floccose

moulds with wet conidia adhering in masses Phialide morphology: long and tapering 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 size: conidia large, 6 - 12 microns long conidia smaller, 3 - 7 microns long Scedosporium apiospermum Phaeoacremonium parasiticum

moulds with wet conidia adhering in masses Presence of collarettes on conidiogenous cells: distinct collarettes present collarettes absent

moulds with wet conidia adhering in masses Collarette morphology: minute and cylindrical flared or reflexed cup-shaped or funnel-shaped Phaeoacremonium parasiticum Pleurostomophora richardsiae Phialophora verrucosa

moulds with wet conidia adhering in masses Presence of two-celled yeasts: two-celled yeasts abundant; large annellidic pegs two-celled yeasts absent, minute annellidic pegs Hortaea werneckii

moulds with wet conidia adhering in masses Conidia arrangement: branched conidiophores of thick-walled segments 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 Growth features: grows at 40C; nitrate test negative (some conidia formed without obvious annellidic pegs) no growth at 40C, nitrate test negative (annellidic pegs visible) Exophalia dermatitidis Exophalia jeanselmei

Sporulation on Sabouraud’s Dextrose Agar mucoraceous moulds Sporulation on Sabouraud’s Dextrose Agar Yes No

Colony morphology and growth: mucoraceous moulds Colony morphology and growth: colonies floccose, rapid growth at 37C colonies floccose, no growth at 37C colonies membranous and waxy, slow growing

mucoraceous moulds Spore formation: spores produced outside a vesicle spores produced inside a sporangia Cunninghamella bertholletiae

Sporangia morphology: mucoraceous moulds Sporangia morphology: sporangia with funnel-shaped bases sporangial base narrowing abruptly to a stalk Lichtheimia corymbifera

stalks with a few side branches mucoraceous moulds Stalk morphology: stalks with a few side branches stalks unbranched

Branching of sporangia mucoraceous moulds Branching of sporangia one or two small sporangia just under main sporangia branches more widely spaced, often curved Rhizomucos pusillus Mucor circinelloides

mucoraceous moulds Colony morphology: colony 3-5mm deep, sporangia grey colony filling the plate air space, sporangia black Rhizomucos pusillus

Stalk and spore morphology: mucoraceous moulds Stalk and spore morphology: stalks about 500 microns long, spores 4-6 microns stalks over 1000 microns long, spores 6-8 microns Rhizopus microsporus Rhizopus arrhizus

Sporangia morphology and Presence of Rhizoids: mucoraceous moulds Sporangia morphology and Presence of Rhizoids: sporangia black, rhizoids prominent at base of stalk sporangia pale or brownish, rhizoids absent Rhizopus stolonifer

some stalks with chlamydospores mucoraceous moulds Colony colour colonies pale yellow colonies pale brown, some stalks with chlamydospores Mucor hiemalis Mucor racemosus

mucoraceous moulds Spore morphology: spores without conical papillae spores with conical papillae Basidiobolus ranarum Conidiobolus coronatus

mucoraceous moulds Nature of spores: motile zoospores produced in liquid culture mucoraceous sporangia produced on special media Pythium spp.

Sporangia morphology: mucoraceous moulds Sporangia morphology: sporangia on funnel-shaped bases 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 Production of fruiting bodies: within 2 weeks after 2 weeks fruiting bodies absent

moulds that produce macroscopic fruiting bodies and miscellaneous moulds Fruiting body morphology: pale-walled fruiting bodies dark-walled fruiting bodies

moulds that produce macroscopic fruiting bodies and miscellaneous moulds Colony colour: colonies white to buff coloured colonies dark purple Aphanoascus fulvescens Monascus ruber

moulds that produce macroscopic fruiting bodies and miscellaneous moulds Fruiting body morphology: thick-walled ascocarps, covered in long brown hyphae Pycnidia, with thin smooth walls Chaetomium spp. Phoma herbarum

moulds that produce macroscopic fruiting bodies and miscellaneous moulds Fruiting body morphology: loose network of dark hyphae flattened, pale-coloured with gills black, with a definite wall Myxotrichum deflexum Schizophyllum commune

moulds that produce macroscopic fruiting bodies and miscellaneous moulds Fruiting body morphology: thick-walled ascocarps, containing asci Pycnidia, with thin smooth walls

moulds that produce macroscopic fruiting bodies and miscellaneous moulds Ascospore morphology: large, mostly five-celled 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 morphology: conidia large, two-celled when mature conidia small, one-celled, pycnidia with spines Lasiodiplodia theobromae Pyrenochaeta romeroi

moulds that produce macroscopic fruiting bodies and miscellaneous moulds Colony morphology: colony flat or folded, velvety, with diffusing brown pigment colony domed, densely floccose, without diffusing pigment Madurella mycetomatis Madurella grisea group

identification of yeasts Colony morphology: minute colonies on glucose peptone agar pink or red colonies on glucose peptone agar white or cream colonies on glucose peptone agar presumptive Rhodotorula spp OR Sporobolomyces spp presumptive Malassezia furfur

identification of yeasts Germ Tube test: positive negative Candida albicans Candida dubliniensis Candida africana

identification of yeasts Presence of capsule: present absent presumptive Cryptococcus spp.

identification of yeasts Urease test: positive negative presumptive Cryptococcus spp. OR Trichosporon spp OR Malassezia pachydermatis

identification of yeasts Presence of chlamydospores on cornmeal agar: present negative Candia albicans Candida dubliniensis

identification of yeasts Presence of arthrospores on cornmeal agar: present negative

identification of yeasts Presence of budding cells on cornmeal agar: present negative dichotomously branching hyphae present presumptive Trichosporon spp OR Saprochaete capitata Geotrichum candidum

identification of yeasts Pseudohyphae present: present negative presumptive Candida spp

Neoscatylidium dimidiatum Microscopic Features Macroscopic Features dy/dx: clinical significance skin and nail infections among immigrants from the tropics and sub-tropics. Not contagious (unlike dermatophytosis)