�ݺ�ߣ

A REVIEW OF IMPORTANT
MYCOTIC AGENTS
ASSOCIATED WITH DISEASE
CONDITIONS IN ANIMALS
BY
OKOROAFOR O.N
OF THE COLLEGE OF VETERINARY SURGEONS
MICROBIOLOGY OPTION
PMC 841
MARCH,2024

MYCOSIS- MYCOSES?
Infections caused by any fungus that
invades the tissues causing superficial,
subcutaneous or systemic disease.
Mycoses can be classified according to;
 the site of infection,
 route of acquisition,
 and type of virulence.
When classified according to the site of infection, fungal
infections are designated as superficial, cutaneous,
subcutaneous, and deep mycoses

Superficial-Cutaneous mycoses
Superficial mycoses
limited to the stratum corneum and essentially elicit no
inflammation.
Cutaneous infections
involves the integument and its appendages, including hair and
nails.
Infection may involve the stratum corneum and deeper layers of the
epidermis.
Cutaneous mycoses involves inflammatory responses that leads to
redness and itching

Subcutaneous Mycoses
Involves the subcutaneous tissues.
Due to fungal invasion of a cut or wound, usually through injury
which leads to rashes, ulcers and other symptoms on your skin.
Deep mycoses
 involves the lungs, abdominal viscera, bones and or central
nervous system.
The most common portals of entry are the respiratory tract,
gastrointestinal tract, and blood vessels.

Mycotic agents vs Superficial
mycoses
Superficial mycoses of greatest importance in companion and
farm animals Includes;
Black piedra (Piedraia hortae),
White piedra (Trichosporon asahii),
Otits and pruritic dermatitis, pityriasis versicolor (Malassezia
spp)

CLINICAL FEATURES
Black piedra:
asymptomatic black and hard nodules, strongly adhered to the
hair shaft of primates and humans.
White piedra:
It appears as lightly pigmented, white to brown nodules with a
soft texture, loosely attached to the hair shaft.
Otits and pruritic dermatitis, pityriasis versicolor:
caused by Malassezia spp
involves only the superficial keratin layer.
 Pruritus,erthyma,scaling and crusting,papulocrustous dermatitis
waxy or greasy exudation,lichenfication and excoriations.

Macroscopic features Piedraia
hortae
• Colonies of Piedraia hortae are slow growing, small, folded, velvety
and dark brown to black in color.
• They may remain glabrous or covered with short aerial hyphae.
Piedraia hortae may produce a reddish brown diffusable pigment.
• From the reverse, the colony is black in color
SAB, 72 hours at 30˚C. Culture is dark
brown to black colonies. Colonies
appear quite dry

Microscopic features Piedraia
hortae
• Septate hyphae, ascostromata, asci, and ascospores are visualized.
• Hyphae are darkly pigmented and contain numerous intercalary
chlamydoconidium-like cells.
• Ascostromata are pseudoparenchymatous structures which are subglobose
to irregular in shape and black in color. Each usually contains a single ascus.
• Asci are ellipsoid, solitary or in clusters and contain 8 ascospores. Ascus
walls dissolve readily.
• Ascospores are hyaline to darkly pigmented. They are one-celled, fusoid,
curved, and taper towards both ends to form the typical whip-like
appendages

Microscopic morphology of Piedraia hortae

Macroscopic Morphology of trichophoron asahii
Colonies of trichophoron asahii gives white to light cream
coloured
colonies which develop a farinose covering (covered with a
whitish, mealy dust)
and has a fissured marginal zone
SAB, 72 hours at 30˚C. Culture almost looks mixed with
lighter and darker colonies. Colonies appear quite dry

Microscopic features of
trichophoron asahii
 Initial culture appears as yeast cells which grow to develop barrel-
shaped arthroconidia.
 Budding cells and lateral conidia are absent.
Microscopic morphology of trichophoron asahii

Clinical features of Malassezia
pachydermatis
Malassezia pachyermatis- the common causes of otits and pruritic
dermatitis in dogs and cats
Hyperpigmented inflammatory lesions in a dog with Malassezia
dermatitis

Macroscopic features of
Malassezia pachydermatis
 Colonies are cream to yellowish on SDA.
Typically smooth to slightly wrinkled lobate margins

Microscopic features OF
Malassezia pachydermatis
under electron microscope,
oThe malassezia organism appears as unique peanut or globose
to ellipsoid in shape,
oround at one end and blunt at the other

MYCOTIC AGENTS VERSES
CUTANEOUS MYCOSES
Cutaneous Mycoses may be classified as
Dermatophytoses or dermatomycoses.
Dermatophytoses are caused by the agents of the genera
Epidermophyton
Microsporum
Trichophyton.
Dermatomycoses are cutaneous infections due to fungi,
the most common of which is
Candida spp.

DERMATOPHYTOSES
Dermatophytoses are characterized by an anatomic site-
specificity according to genera. For example,
Epidermophyton floccosum infects only skin and nails, but
does not infect hair shafts and follicles.
 Microsporum spp. infect hair and skin, but do not involve
nails.
 Trichophyton spp. may infect hair, skin, and nails.

DERMATOPHYTES
Dermatophytes species Main source Others
Microsporum canis Cat, dog, horse All mammals
Microsporum gallinae poultry Dog, cat
Microsporum gypseum Soil All mammals
Microsporumn anum Soil Pig
Microsporum persicolor Microtid rodents Dog, cat
Trichophyton equinum Horse Cat, dog (rare)
Trichophyton erinacei Hedgehog Dog
Trichophyton
mentagrophytes
Rodents All mammals
Trichophyton simii Primate Fowl, dog, cat
Trichophyton verrucosum Cattle, other ruminants All mammals

CLINICAL FEATURES OF
DERMATOPHYES
 inflammation with erythermatous sign that is
more severe at the edge of lesion.
The center area of the lesion is clear in most of
glabrous skin infection.
Hair infection becomes brittle and loosed from
some area forming alopecia,

MACROSCOPIC/MICROSCOPIC FEATURES OF
Epidermophyton spp
MACROSCOPIC FEATURES
The colony aspects are filamentous turning into powder surface,
Central poor radial grooves and white color turning into yellow-green
or mustard-yellow
Brown-yellow reverse in Sabouraud dextrose agar at 25°C.
MICROSCOPIC FEATURES
The macroconidia are broadly clavate with typically smooth, thin to
moderately thick walls and one to nine septa, 20 to 60 by 4 to 13 mm
in size.
They are usually abundant and borne singly or in clusters.
 Microconidia are absent.

A. Macroscopic Morphology OF Epidermophyton spp on SDA at 25C B.
Microscopic feature showing the macroconidia

MACROSCOPIC/MICROSCOPIC
FEATURES OF MICROSPORUM spp
Macroscopic features
The colony aspects are plane, velvety or cottony surface, white or yellowish
color.
Brown or golden yellow reverse in Sabouraud dextrose agar at 25°C
Microscopic features
Macroconidia are characterized by the presence of rough walls which may be
asperulate, echinulate, or verrucose.
They are fusiform, obovate (egg shaped) or cylindrofusiform.
They may also have thin, moderately thick to thick walls and 1 to 15 septa and
range in size from 6 to 160 by 6 to 25 mm.
Microconidia are sessile or stalked and clavate and usually arranged singly along
the hyphae or in racemes

A Macroscopic Morphology of Microsprum spp on SDA at 25C B.

MACROSCOPIC /MICROSCOPIC
FEATURES of TRICHOPYTON spp
The colony aspects are plane, white to cream color, powdery to granular
surface
Reverse is yellowish brown to reddish-brown in Sabouraud dextrose agar at
25°C.
Macroconidia, have smooth, usually thin walls and one to 12 septa, are
borne singly or in clusters, and may be elongate and pencil shaped, clavate,
fusiform, or cylindrical.
They range in size from 8 to 86 by 4 to 14 mm.
 Microconidia, usually more abundant than macroconidia, may be globose,
pyriform or clavate, or sessile or stalked, and are borne singly along the sides
of the hyphae or in grape-like clusters

•
A. Macroscopic Morphology OF Trichophyton spp on SDA at 25C B.

SUBCUTANEOUS MYCOSES
There are three general types of subcutaneous mycoses:
Chromoblastomycosis,
Mycetoma
Sporotrichosis.
All appear to be caused by traumatic inoculation of the etiological
fungi into the subcutaneous tissue.

CLINICAL FEATURES
Chromoblastomycosis is a subcutaneous mycosis characterized by
verrucoid lesions of the skin (usually of the lower extremities)
Chromoblastomycosis is generally limited to the subcutaneous tissue with
no involvement of bone, tendon, or muscle.
Mycetoma is a suppurative and granulomatous subcutaneous mycosis,
which is destructive of contiguous bone, tendon, and skeletal muscle.
Mycetoma is characterized by the presence of draining sinus tracts from
which small but grossly visible pigmented grains or granules are extruded.
Sporotrichosis involves the subcutaneous tissue at the point of traumatic
inoculation. The infection usually spreads along cutaneous lymphatic
channels of the extremity involved.

MYCOTIC AGENTS VERSUS
Chromoblastomycosis are
 Fonsecaea pedrosoi,
 Fonsecaea compacta,
 Cladosporium carionii,
 Phialophora verrucosa.
Mycetoma
 Pseudallescheria boydii
 Nocardia brasiliensis.
Sporotrichosis
 Sporothrix schenckii

Macroscopic/ microscopic features
features of fonsecaea spp.
The fungal colonies were greenish black with a velvety heaped and
folded surface and were covered with silvery mycelium.
Upon further incubation, colonies developed a cone-shaped convex
protrusion at the center.
The isolate has brown branching hyphae with septate,
Compactly sympodial conidiophores with slightly swollen tips,
which give rise to single-celled, ovoid primary conidia (1.5–3 × 2.5–
6 μm).

fonseacaea spp
Macroscopic Morphology OF fonseacea spp on SDA at
25C B. Microscopic feature showing the branching hyphae

Fonseaca Pedrosoi infection in a
dog
A, dog presented with lesions on the ventral abdomen. B, tissue sections
showing the presence of hyphae Grocott-
Gomori methenamine silver stain. 4003. C, fungal colonies growing on
Sabouraud dextrose agar. D, lactophenol cotton blue stain of the

Macroscopic /Microscopic features of
Cladosporium spp
Macroscopic feature
The growth rate of Cladosporium colonies is moderate on
potato dextrose agar at 25°C .
 the texture is velvety to powdery.
 the color is olivaceous green to black from the front and black
from the reverse.
Microscopic feature
Cladosporium spp. produce septate brown hyphae, erect and
pigmented conidiophores, and conidia.

Macroscopic Morphology OF Cladosporium spp on PDA at 25C B.
Microscopic feature showing the septated brown hyphae

Macrosopic features of Phialophora
verrucosa
Colonies are woolly to velvety, dark grey, brown or olivacious black on the
surface and reverse
SAB agar at 10 Days incubation

Microscopic feature of Phialophora
verrucosa
Hyaline to brown, septate hyphae.Phialides are pale brown to brown,
bottle or vase or shaped with a darker collarette at the apical end.
Phialides are located laterally or terminally on the hyphae.
Conidia are unicellular, smooth and thin walled, hyaline to brown and
round or ovoid (1-3 X 2-4 µm) which accumulate at the apex of the
collarette giving the appearance of a vase of flowers

MACROSCOPIC/MICROSCOPIC FEATURES OF
Pseudallescheria boydii
Macroscopic feature
Moderately rapid growing colony at 25C which matures in about
a week.
Texture is woolly to cottony.
Colony is white becoming greyish or smokey-brown on the
surface; reverse is pale with brownish-black zones.

Microscopic feature
• Hyphae are hyaline, septate (2 - 4 µm dia.)
• Conidiophores bearing annellides are of varying length and exhibit little
differentiation from the vegetative hyphae.
• Conidia (annelloconidia) are unicellular, pale brown, ovoid with truncate
bases formed singly or in small clusters at the ends of the conidiophores or
from short annellidic necks arising directly from the hyphae.
• Ascospores are yellow-brown and ellipsoidal in shape.

Macroscopic Morphology of Sporothrix
spp
 Moderately rapid to rapid growth, with the colony becoming mature
within 7 days.
Generally cream colouration on SDA orPDA.
As the fungus matures, a salt & peppery brown or black colour
develops with the colony retaining a narrow whitish border..
The reverse of darkly pigmented colonies is usually dark in the center
with a progressively lighter periphery.
Sporothrix initially has a moist appearance but becomes wrinkled and
leather to velvety in texture as it ages

Sporothrix spp
SAB, 30ᵒC, 3 weeks incubation

Microscopic Morphology of Sporothrix
spp
Sporothrix produces narrow (1 – 2 µm dia.) hyaline, septate and
branching hyphae.
Sporothrix produces Slender, tapering conidiophores arise at right
angles from undifferentiated hyphae.
 Hyaline conidia are produced at a small swelling at the conidiophores
apex by sympodial growth resulting in a “rosette-like” appearance.
Single thick-walled brown to black (dematiaceous) sessile conidia (2 –
4 µm dia.) can also be present, arising directly from the hyphae.

Sporothrix schenckii .
(1000+10X. LPCB, DMD-108)

DEEP MYCOSES
Deep mycoses are caused by primary pathogenic and
opportunistic fungal pathogens.
The primary pathogenic fungi are able to establish infection in a
normal host.
Opportunistic pathogens require a compromised host in order to
establish infection (e.g., cancer, organ transplantation, surgery,
and AIDS).
The primary deep pathogens usually gain access to the host via
the respiratory tract.
Opportunistic fungi causing deep mycosis invade via the
respiratory tract, alimentary tract, or intravascular devices.

MYCOTIC AGENTS VERSUS DEEP
MYCOSES
The primary systemic fungal pathogens include
• Coccidioides immitis,
• Histoplasma capsulatum,
• Blastomyces dermatitidis,
• Paracoccidioides brasiliensis.
The opportunistic fungal pathogens include
Cryptococcus neoformans,
Candida spp
Aspergillus spp
Penicillium marneffei,
Zygomycetes,
Trichosporon beigelii,
 Fusarium spp.

MACROSCOPIC FEATURE OF
Coccidioides immitis
culture of Coccidioides immitis on Sabouraud's medium, showing white, cottony fungus growth
Coccidioides immitis colonies grow rapidly.
The colonies are moist, glabrous, membranous, and grayish initially,
later producing white and cottony aerial mycelium At 25 or 37°C and
on Sabouraud dextrose agar,. With age, colonies become tan to
brown in color.

MICROSOPIC FEATURES OF
Coccidioides immitis
Hyphae and arthroconidia are produced. Hyphae are hyaline, septate and
thin.
 Arthroconidia are thick-walled, barrel-shaped, and 2-4 x 3-6 µm in size.
Typically, these arthroconidia alternate with empty disjunctor cells.

Macroscopic/Microscopic
Morphology of Histoplasma spp
A) The colonies of Histoplasma capsulatum on Columbia blood agar medium after subculture, the fungus is milky
white with villous hyphae in the outer ring. (B) Cogwheel-like macroconidia of Histoplasma capsulatum stained
with Lactophenol cotton blue after subculture, ×400 magnification. (C) Hyphae and spores are bright blue
fluorescent in Fluorescence staining, 100× magnification. (D) Lactophenol cotton blue staining in primary culture
with cogwheel-like macroconidia, ×400 magnification

Macroscopic Morphology of
Cryptococcus spp
Cream-colored smooth, mucoid, yeast-like colonies.

Microscopic Morphology of
Cryptococcus spp
Numerous yeast cells, many budding, along with other
bacteria in this sputum sample. A large epithelial cell is seen
in the lower left.

Morphology of Aspergillus niger
Rapidly growing on Saboraud-Dextrose Agar starting with a
white to yellowish felt-like mat of mycelia, quickly turning black
as conida develop the pigment aspergillin during maturation.
Reverse remains white to pale in colour.
Microscopic Features
• Septate, hyaline (clear) hyphae.
• Conidiophores (Stipes) are long (400-3000 µm) with spherical
vesicles at the apex measuring 30-75 µm.

Morphology of Aspergillus niger
Aspergillus niger on Sabouraud-Dextrose Agar 72
hrs at 30C Black pigment from conidia maturing
from center of colony
Large vesicle at end of broken conidiphore bearing
metulae & phialides with black pigmented conidia
already dispersed.

Morphology of Aspergillus flavus
Macroscopic Morphology;
Very rapid rate of growth, maturing in about three days.
Surface is greenish-yellow to olive and may have a white border.
Texture is often floccose, especially near the center and overall can be velvety to
woolly.
Unremarkable cream to tan to yellowish reverse on Sabouraud Dextrose media
Microscopic Morphology
Septate hyphae with rather long conidiophores (~400-800 X 8-17 µm) which have
a rather rough texture or even spiny, especially just below the vesicle.
Vesicles are spherical to elongate and about 20 – 45 µm wide.
Conidia are globose to ellipsoidal (3-6 µm) with smooth to finely roughened walls.

COLONIAL MORPHOROLOGY OF
ASPERGILLUS FLAVUS
Aspergillus flavus on SAB media at 72 hour at 30o
C
(note greenish-yellow colour with white edge)
Tangled web of the
Aspergillus flavus
mycelium as above
(X250

Macroscopic Morphology of Aspergillus
fumigatus
The surface growth is velvety, downy or powdery, showing various
shades of green, most commonly a blue-green to a grey-green with a
narrow white border.
The colour typically darkens with age.
The reverse is white to tan to pale yellowish.
Aspergillus fumigatus on SAB Agar after 5
days incubation at 30o
C

Aspergillus fumigatus
Hyphae are septate with smooth walled conidiophores (usually
less than 300 µm in length and 5-10 µm wide).
 Vesicles are subclavate in shape, roughly 20-30 µm in width.
Conidiogenous cells (phialides) are flask shaped, uniseriate,
compact (closely spaced), usually forming on the upper two-
thirds of the vesicle and mature parallel to the axis of the
conidiophore (columnar formation).
 Young conidial heads may radiate. Conidia are verrucose
(smooth or slightly rough), (sub)spherical and about 2-3.5 µm in
diameter and develop in chains.

MICROSCOPIC MORPHOLOGY A
FUMIGATUS

PENICILLIN spp
Most species exhibit rapid growth and become fully mature in
about 5 days.
The surface appearance is usually described as velvety to
powdery. The colony colour varies with the species but is
usually a green, blue-green or grey-green, often with a white
edge.
Exudates of various colours may also form on the surface.
The reverse usually a pale cream to yellow but may be a more
intense reddish-brown.

COLONIAL MORPHOLOGY OF
PENICILLIUM SPP
Penicllium species on SAB media. Many species are rapid growing at day
7 at30o
C

Microscopic Morphology of
Penicillin spp.
Penicillium species - hefty phialides , Rough conidia
produced by this species.
(LPCB, 1000X, DMD-108)

HANDS ON PRACTICAL
• MOST OF THE MYCOTIC AGENTS MENTIONED ABOVE
ARE MAINLY OF HUMAN ORIGIN.
• INVESTIGATE REPORTS OF THESE MYOCTIC AGENTS
WITH DISEASES OF ANIMAL ORIGIN
STATING
CLINICAL FEATURES
LABORATORY DIAGNOSIS
• INSERT PICTURES WHERE POSSIBLE

REFERENCES
• Bodey GP (ed.): Candidiasis. 2nd ed. Raven Press. pp. 1, 1992 .
• Dupont B, Denning DW, Marriott D, Sugar A, Viviani MA, Sirisanthana T, Elewski,, BE (eds.): Cutaneous Fungal Infections. Topics in Clinical Dermatology. Igaku-Shoin. pp. 1, 1992 .
• Kwon-Chung KJ and Bennett JE: Medical Mycology. Philadelphia: Lea & Febiger, 1992 .
• Matsumoto T, Ajello L, Matsuda T, Szaniszlo PJ, Walsh TJ. Developments in phaeohyphomycosis and hyalohyphomycosis. J Med Vet Mycology. 1994;32 (suppl 1):329. [PubMed]
• McGinnis MR: Laboratory Handbook of Medical Mycology. New York: Academic Press, 1980 .
• Mycoses in AIDS patients. J Med Vet Mycol; 32 Suppl 1:65, 1994 . [PubMed]
• Odds FC, Arai T, DiSalvo AF, Evans EGV, Hay RJ, Randhawa HS, Rinaldi MG, Walsh TJ. Nomenclature of fungal diseases. J Med Vet Mycol. 1992;30:1. [PubMed]
• Odds FC: Candida and Candidosis. A Review and Bibliography. 2nd ed. Philadelphia: Bailliere Tindall; 1988 .
• Pappagianis D. Coccidioidomycosis. Semin Dermatol. 1993;12:301. [PubMed]
• Pfaller MA and Fromtling RA (eds): Mycology. In P Murray, EJ Baron, MA Pfaller, FC .
• Tenover, RH Yolken (eds). Manual of Clinical Microbiology. 6th. ed. American Society for Microbiology. Washington, D.C. pp. 699, 1994 .
• Rinaldi MG, Dixon DM (eds.). The evolving etiologies of invasive mycoses. Infect Dis Clin Pract. 3 (suppl):S47, 1994 .
• Rippon JW: Medical Mycology. The Pathogenic Fungi and The Pathogenic Actinomycetes. 3rd ed. Philadelphia: WB Saunders Co; 1988 .
• Sarosi G and Davies S: Fungal Diseases of the Lung, 2nd. ed. Raven Press, New York, NY; pp. 1, 1993 .
• Sternberg S. The emerging fungal threat. Science. 1995;266:1632. [PubMed]
• Viviani MA, Hill JO, Dixon DM: Penicillium marneffei: dimorphism and treatment. p.413–423. In Vanden Bossche, H., Odds, FC, and Kerridge, D. (eds) Dimorphic Fungi in biology and
medicine. Plenum Press. New York, 1993 .
• Walsh TJ, DePauw B, Anaissie E, Martino P. Recent advances in the epidemiology, prevention, and treatment of invasive fungal infections in neutropenic patients. J Med Vet Mycol.
1995;32 (Supplement 1):33. [PubMed]
• Walsh TJ, Gonzalez C, Lyman CA, Chanock S, Pizzo PA. Invasive fungal infections in children: recent advances in diagnosis and treatment. Advances in Pediatr Infect Dis. 1995;11:175. [
PubMed]
• Walsh TJ, Pizzo PA. Nosocomial fungal infections. Ann Rev Microbiol. 1988;42:517. [PubMed]

�ݺ�ߣ

Share MYCOLOGY 841 power point present for college students

More Related Content

Share MYCOLOGY 841 power point present for college students