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MYCOLOGY REVIEW
Fungi vs. Bacteria:
Criteria Bacteria Fungi
Yeast Mold
Size 3 microns 3 microns at least
(like bacteria)
3 feet
Cellular differentiation Unicellular Unicellular Multicellular
Nuclear & cell
structure Prokaryotic Eukaryotic
Chemical Composition
Cell Wall
Cell Membrane
Peptidoglycan
(-) Sterols (except
Mycoplasma)
Chitin, Glucan & Mannans
(+) Sterols – “Ergosterols”
Reproduction Asexual (Binary Fission) Asexual (B.F.) and Sexual
Spore For Adverse conditions
Thermoresistant
For Reproduction
Not Thermoresistant
Life Cycle Simple Simple complex
Morphology:
Dimorphism – the ability to exist as two morphologic forms
Thermally dimorphic – dimorphism is induced by change in temperature
YEASTS/SPIRULES MOLDS
Body Temp. Room Temp.
Animal Habitat Natural Habitat
Parasitic Saprobic
Facultative anaerobes Aerobes
Reproduce via
Budding or
Sporulation
Sporulation
Yeast phase Hyphal/Mycelial phase
Exist at conditions:
↑ Temp
↓ O2
↓ Nutrients
↓ Temp
↑ O2
↑ Nutrients
Hyphae of mold can be classified:
1. Septate/Non-septate
a. Septate – with crosswalls; unicellular per septation; can still reproduce when it breaks
b. Non-septate – coenocytic/aseptate; continuous; multicellular; cannot survive when it breaks
2. Reproductive/Vegetative
a. Reproductive – aerial; sprout from vegetative hyphae vertically; produce sexual spores
b. Vegetative - anchors fungus to substrate; absorbs nutrients and water
3. Hyaline/Dematiaceous
a. Hyaline – non-pigmented
b. Dematiaceous – pigmented (black-brown)
Tissue forms: what we see in histopathologic examination (so, kapag may microscope sa prax, ito lang ang madalas na nasa pointer)
YEAST CELLS Organism Disease Type of Mycoses
Intracellular Histoplasmosis capsulatum Histoplasmosis Endemic Respiratory
Broad-based Blastomyces dermatitidis Blastomycosis Endemic Respiratory
Multiple buds (like a mariner’s
wheel)
Paracoccidioides braziliensis Paracoccidioidomycosis Endemic Respiratory
Encapsulated Cryptococcus neoformans
Cryptococcus gatti
Cryptococcosis Opportunistic
With Transverse septum Penicillium marneffei Penicilliosis marneffei Endemic Respiratory
Cigar-shaped Sporothrix schenckii Sporotrichosis Subcutaneous
HYPHAE
Coenocytic Zygomycetes Zygomycosis Opportunistic
Dichotomously branched Aspergillus spp.
A.fumigatus (most common)
Aspergillosis Opportunistic
Hyaline, septate Dermatophytes Dermatophytosis Cutaneous
Demetiaceous, septate Several dematiaceous fungi
Phaeoanneliomyces wernekii
Phaeohyphomycosis
Tinea nigra
Subcutaneous
Superficial
YEAST CELLS &PSEUDOHYPHAE Candida spp.
C. albicans (most common)
Candidiasis Opportunistic
GRANULES Several dematiaceous and non-
dematiaceous fungi
Mycetoma Subcutaneous
SPHERULES Coccidiodes immitis Coccidioidomycosis Endemic Respiratory
FISSION/SCLEROTIC BODIES Several dematiaceous fungi Chromomycosis Subcutaneous
The next part is a compilation of all the diseases we tackled in our mycology module. Dr.Padla said that our prax will include the laboratory
diagnosis-part of our lectures.
Capsule:
Some fungi have
capsules.
Cryptococcus
neiformans – the
only pathogenic
yeast which has a
capsule
Thermally dimorphic fungi in our
mycology module:
- Sporothrix schenckii
- Histolasma capsulatum
- Blastomyces dermatidis
- Coccidioides immitis
- Paracoccidioides braziliensis
- Penicillium marneffei
2
I. SUPERFICIAL MYCOSES
limited to the stratum corneum, the dead layer of the skin
affect only nonliving tissues
also called “tineas” (larva, worm)
infections are usually cosmetic problems, easily diagnosed and treated
Ptyriasis versicolor
Etiology: caused by Malassezia furfur,
Tissue form: short hyphae and clusters of yeast-like cells
Infectious form: short hyphae and clusters of yeast-like cells
Laboratory Diagnosis:
o KOH examination: skin scrapings
o Spaghetti and meatball appearance (short hyphae and clusters of yeast-like cells)
o Wood’s lamp: lesions fluoresce golden yellow
o Cannot be cultured unless olive oil and fatty acids are incorporated
Tinea Nigra
Etiology: caused by Phaeoanneliomyces wernekii
Tissue form: dematiacious hyphae
Infectious form: dematiacious hyphae
Laboratory Diagnosis: direct microscopic exam’n:
KOH treated skin scrapings: pigmented budding cells, budding fragments, blanching hyphae
Piedra
Black Piedra White piedra
Etiology:
Piedra hortae
Hair shaft: perfect (teleomorphic) state
spindle-shaped ascospores w/in
asci develop
Culture: asexual (anamorphic) state
slow growing brown to reddish
hyphae with many
chlamydoconidium-like cells
Trichosporon beigelii
yeast-like, hyphae that fragmnet into
arthroconidia
Laboratory
Diagnosis
KOH: (crushed nodules)
- asci containing fusiform ascospores with
whiplike extensions
Direct KOH: septate hyphae that fragment into
arthroconidia wc rapidly round up
Blastoconidia may be present along hyphae
Confirmed by culture
II. CUTANEOUS MYCOSES
a.k.a. Dermatophytoses; normally called “tinea” and more commonly “ringworms”
result of the host reaction to the enzymes released by the fungus during its digestive process
involve infections that extent into the (epidermis/outer keratinized layer SKIN, HAIR, and NAILS
Living tissue not invaded; systemic spread is rare
Most common human mycoses
CAUSE: Dermatophytes
o “keratinophilic fungi”; able to utilize keratin as nitrogen source
o Dermatophytes classified according to:
Ecological niche or habitat:
1. Anthropophilic – exclusively in association with humans
2. Zoophilic – found in association with domesticated and wild animals and birds
3. Geophilic – species frequently isolated from the soil
3 Genera:
These genera, in the anamorphic (asexual) state, are classified according to sporulation patterns,
morphologic features and nutritional requirements:
1. Trichophyton – infects skin, hair and nails (tip: three=Tri)
2. Microsporum – infects skin and hair (tip: MSH)
3. Epidermophyton (E. flocossum)– infect skin and nail (tip: ESN)
Trichophyton Microsporum Epidermophyton
1. T. rubrum 1. M. cruisis 1. E. floccosum
3
2. T. mentagrophytes 2. M. gypseum
3. T. verrucosum 3. M. audoinii
4. T. tonsurans 4. M. ferrugineum
5. T. suodanese 5. M. canis
6. T. violaceum
7. T. schoenleinii
8. T. concentricum
GENERAL CHARACTERISTIC OF THREE GENERA:
GENUS MACROCONIDIA MICROCONIDIA
Trichophyton Usually rare, smooth, pencil-
shaped, thin-walled, normally
contain 3-8 cells
Few to numerous, round or
oval, borne singly or in grape-
like clusters
Microsporum Numerous, rough, spindle-
shaped, echinulate, thick-
walled, singly, usually contains
3-7 cells
Few club-shaped, borne singly,
usually present
Epidermophyton Numerous, smooth-walled,
club-shaped, formed singly, in
pairs or clusters, contain 2-4
cells in groups
Absent
TRICHOPHYTONS
SPECIES MACROCONIDIA MICROCONIDIA
T. rubrum Variable number Oval shape, periform, singly
along hyphae
T. mentagrophytes Not always present Numerous, borne in clusters
T. verrucosum Absent Absent
T. tonsurans Rare and irregular form Numerous, tear/club shape
T. suodanese Absent Tear shape along hyphae
T. violaceum Rare/Absent Rare/Absent
T. schoenleinii Absent Rare
T. concentricum Absent/Rare Absent/Rare; balloon shape
MICROSPORUMS
SPECIES MACROCONIDIA MICROCONIDIA
M. cruisis Numerous, long, rough knob
like ends, spiky, with many
cells
M. gypseum Numerous, symmetric, with
round ends, smooth walled
M. audoinii Distorted if present
M. ferrugineum Rare, resemble those of M.
canis
M. canis Smooth edge, round ends,
knob-like
EPIDERMOPHYTON
SPECIES MACROCONIDIA MICROCONIDIA
E. floccosum Smooth, club-shaped with
rounded ends, numerous
Absent
Trichophyton Microsporum Epidermophyton
Infects: skin, hair & nails Infects: skin & hair Infects: skin & nails
Transmission:
Human to human
Animal to human
Transmission:
Human to human
Animal to human
Soil to human
Transmission:
Human to human
TISSUE FORMS AND INFECTIOUS PARTICLES:
o hyaline septate hyphae
SELECTIVE MEDIUM USED:
o Mycobiotic Agar containing Cyclohexamide (inhibits saprophytic fungi growth) Chloramphenicol and Gentamycin (inhibits
bacterial growth to prevent contamination)
LABORATORY DIAGNOSIS:
o KOH exam of skin scrapings, hair stubs/roots, nail clippings
shows hyaline, septate hyphae
o Wood’s Lamp Examination
Fluorescence in cases of tinea capitis cause by Tinea schoenleinii, Microsporum canis and Microsporum audouinii
4
o Culture on Mycobiotic Agar
Cultural and morphological; characteristics used in species identification
CONFIRMATORY TESTS:
Hair Penetration Test – distinguishes Tinea mentagrophyte from Tinea rubrum
o Urease Test - distinguishes Tinea mentagrophyte from Tinea rubrum
NOTE: In annular lesions with central clearing and advancing border sample is obtained from the edge to yield a more
positive result and prevent false negative
Dermatophytes have no blastoconidia because they are not a budding yeast
They are seldom cultured
7 DIFFERENT TYPES OF DERMATOPHYTOSES:
TINEA CAPITIS
CAUSES: Microsporum species and Trichophyton species
Types of Tinea capitis with different causative agents:
o Microsporum audouinii infections
grey patches covered with scales develop with broken stumps of the infected hair
hair stumps are surrounded by spores hence ECTOTHRIX type of hair infection
o Kerion
Greater inflammatory reaction caused by Microsporum canis
Caused by spores of animal origin
A severe inflammatory type characterized by boggy, tumid, suppurating mass studded with pustules and broken
hair.
When the condition resolved, there may be areas of permanent hair loss.
o “black dot” tinea capitis
produced by Tinea violaceum and Tinea tonsurans
hairs are invaded within the shaft hence ENDOTHRIX type of hair infection
it breaks off at the surface of the hair shaft leaving stumps that look like black dots in the follicles
NOTE: An endothrix infection will always indicate that the pathogen is anthrophilic in origin
o Favus
Caused by Tinea schoenleinii
Affects mainly the scalp and is characterized by scutula (cup-shaped disc around the hair follicle with a peculiar
moussy odor) and cicatricial alopecia
ENDOTHRIX
LABORATORY DIAGNOSIS:
o Wood’s light – suspected hair infection should always be examined under Wood’s light (UV >365 nm) as lesion of M.
canis and M. auduoinii show a diagnostic brilliant yellow-green fluorescence. Those due to T. schoenleinii may cause a
grey-green fluorescence.
o Direct microscopic examination
o Culture
TINEA BARBAE
CAUSES: Microsporum species and Trichophyton species acquired from animals
LABORATORY DIAGNOSIS:
o Direct microscopic examination
o Culture
TREATMENT:
o Systemic griseofulvin
o Clipping or shaving the beard is recommended
TINEA CORPORIS
CAUSES: Microsporum species, Trichophyton species and Epidermophyton floccosum
o Microsporum species are the predominant cause of tinea corporis in children
TINEA IMBRICATA
CAUSE: Trichophyton concentricum
LABORATORY DIAGNOSIS:
o Direct microscopic examination of scrapings in 10%-20% KOH
o Culture
TINEA CRURIS
5
CAUSES: T. mentagrophyte or T. rubrum, E. floccosum
LABORATORY DIAGNOSIS:
o Direct microscopic examination
o Culture
TINEA PEDIS
CAUSES: T. mentagrophyte or T. rubrum, E. floccosum
o T. mentagrophyte commonly produces an inflammatory type of tinea pedis whereas T. rubrum produces a chronic type
LABORATORY DIAGNOSIS:
o Direct microscopic examination
o Culture
TINEA MANUUM
CAUSES: T. mentagrophyte or T. rubrum, E. floccosum
LABORATORY DIAGNOSIS:
o Direct microscopic examination
o Culture
TINEA UNGIUM
CAUSES: Trichophyton species and E. floccosum
LABORATORY DIAGNOSIS:
o Direct microscopic examination of the nail
o Culture
TREATMENT:
o All nail infections are extremely resistant to treatment
o Systemic griseofulvin after identification of the agent
Dermatophytoses Location
Tinea capitis Scalp hair
Tinea barbae Beard hair
Tinea corporis Non-hairy smooth skin
>Tinea imbricata
Tinea cruris Groin
Tinea pedis Interdigital spaces of feet
Tinea manuum Hand
Tinea ungium Nail
III. Subcutaneous Mycoses
It is characterized by deep ulcerating lesions usually developing at the site of the trauma where the fungus is implanted.
It involves the deeper layer of the dermis, subcutaneous tissues and bone systemic spread.
Mimics some bacterial infections, with the exception of sporotrichosis
Causative organisms are ubiquitous in nature, cultural isolation wouldn’t be enough. Tissue invasion must be demonstrated by KOH
and tissue preparations.
Sporotrichosis
A. Etiology
Sporothrix schenckii
Yeast forms inside infected tissues
At 250, the fungus is a mold
B. Laboratory Diagnosis
Clinical materials use in laboratory examination include pus from abscesses, biopsy materials of subcutaneous or organ
lesions or sputum in cases of pulmonary infection
KOH mount is not diagnostically useful since organisms are sparse
Round to oval to cigar-shaped yeast cells can be demonstrated better with GMS stain rather that tissue smears
Asteroid bodies represents the host immune response (basophilic yeast surrounded by eosinophilic rays)
Culture is necessary to confirm diagnosis; colonies are initially white and membranous becoming black and leathery by age
Mycetoma (Madura Foot)
6
It is characterized by swelling, abscess formation and draining
A. Etiology
Eumycetoma (true fungi) Exophiala jeanselmei, Pseudallescheria boydii, Madurella mycetomatis and Madurella grisea
Actinomycetoma(bacteria) Actinomadura madurae, Actinomadura pelletieri, Streptomycis somaliensis, Nocardia braziliensis,
and Nocardia asteroids
B. Epidemiology
Saprophytes from the soil and is acquired by direct inoculation
C. Laboratory diagnosis
So that you can distinguish between a bacteria and a fungal infection
KOH examination (Direct microscopic examination) presents granules that shows the etiologic agents; color is species
specific
Culture is also use to identify the species
Chromomycosis
Dark brown nodules at site of infection
A. Etiology
Dematiaceous (black) fungi
Fonsecaea pedrosoi, Foncecaeae compactum, Phialophora verrucosa and Cladosporum carrionii
B. Laboratory Diagnosis
KOH in skin scrapings or histopathological infection; crushed black dots appear as thick walleddark brown, 5-12 mm in
diameter, round and sclerotic bodies with single or multiple cells formed by crosswalls
Brown, blanched distorted hyphae may also be present
Culture techniques are also done for taxonomic identification; slow growing, black colonies
Phaeohyphomycosis
Localized subcutaneous infection forming granulomas, cysts and abscesses.
A. Etiology
Several dematiaceous fungi
B. Laboratory Diagnosis
Histopathological examination; Organisms are seen as pigmented, septate hyphal fragments
Culture for taxonomic identification; dark colored colonies develops
IV. Opportunistic Mycoses
Candidiasis
A. Etiology
Candida albicans, C. tropicalis, C. krusei, C. parapsilosis and C. glabrata
B. Clinical disease
1. Superficial Candidiasis
The most common diseases involves the skin, nails and mucosal surface of the vagina, mouth esophagus and the
bronchial tree; Skin and nail infections usually mimics dermatophytoses
Cutaneous mycoses as seen in diabetics
Candidiasis of the nail usually causing hardening and thickening of the nail
Vulvovaginal candidiasis is also seen in diabetics and can be transferred sexually
Thrush (oral) usually presents white, creamy patches on the mucus membranes and corners of the mouth
C. Laboratory Diagnosis
KOH examination of the infected nail, skin, mucosal scrapings; in most instances, blastoconidia are seen singly or in
clusters at the constrictions of their pseudohyphae
Histopathological examination of C. albicans are demonstrated as budding yeast of pseudohyphae or both
Culture; in isolation media, C albicans grows as opaque cream colored colonies with pasty consistency while in microscopic
examination, pseudohyphae with clusters of round blastoconidia are seen
Germ tubes at 370 in serum identifies C. albicans
7
SYSTEMIC MYCOSES
- Most serious of all mycoses
- Originate primarily in the LUNGS
- Major types:
Endemic Respiratory Mycoses
A. Histoplasmosis
B. Blastomycosis
C. Coccidioidomycosis
D. Paracoccidioidomycosis
E. Penicilliosis marneffei
Opportunistic Mycoses
A. Candidiasis
B. Aspergillosis
C. Cryptococcosis
D. Zygomycosis
Endemic Respiratory Mycoses
- Portal of entry: Respiratory Tract
- Mode of Transmission: Inhalation of infectious conidia
- Infectious form: conidia (asexual form)
Agents:
- have restricted geographic distribution (area where the fungi thrive)
- exhibit thermal dimorphisms with 2 forms:
Yeast – seen at 37 degrees Celsius
Mold – seen at room temperature, natural habitat
- primary site of infection = lungs
- Microconidia – infectious form; the small the size, the better.
MYCOSES OCCUR AS CAUSED
BY
INFECTIOUS
PARTICLE
DIAGNOSIS (KOH/
histopath exam) →
TISSUE FORM
CULTURE AT ROOM
TEMPERATURE
(Saboraud’s Agar)
27C
At 37 Celsius (BHI)
Histoplasmosis
/
Darling’s/
Caver’s/
Spelunker’s
disease
Pulmonary (PTB
like) 60%
asymptomatic and
40% primary
pulmonary
histoplasmosis
Disseminated
infection with
(RES)
Reticuloendotheli
al System
involvement and
muco-cutaneous
infection
Histoplasm
a
capsulatu
m
Ascomycet
e
-Thermally
dimorphic
-
facultative
intracellula
r
-grows in
soil
contaminat
e by bat or
bird
excreta
Microconidia
(can easily go
through the
lungs and
settle in the
alveoli)
Small round to oval
intracellular yeast
cells often with
histiocytes
finding yeast cell in
tissues does not
diagnose
Histoplasmosis,
others are
histoplasma
fine septate hyphae
(hyaline)
tuberculate
macronidia (means
spikes around the
structure) and small
micronidia (both
seen in Lactophenol
Cotton Blue Mount)
which is diagnostic
of H. capsulatum
(infectious particle)
non-capsulated
creamy, pasty yeast
colonies
small oval yeast cells
(cluster – self yeast
cells)
non-infectious,
patient can’t transmit
Importance of
observation at Body
Temp: Demonstrate
dimorphism: Hyphae
(from culture)
yeast cell (seen
microscopically,
budding not
intracellularly)
Blastomycosis
aka “North
American
Blastomycosis’
PTB – like but
with lesser
calcifications
Cutaneous –
result of infection
of the skin or
sometimes a
manifestation of
disseminated
form;
microabscesses;
crusty, elevated
lesions
Disseminated –
with lower
percentage
Blastomyc
es
dermatitidi
s
Ascomycet
e
-Thermally
dimorphic
- soil
saprophyte
“conidia” /
microconidia
(No
macroconidia
)
Round, double-walled
yeast often with
single bud connected
by a broad base
(bowling pin
appearance)
Pyriform conidia
borne singly on
septate hyphae (on
Lactophenol Cotton
Blue mount)
Double-walled yeast
cells with single
broad-based bud
seen also in
KOH/histopath
8
MYCOSES OCCUR AS CAUSED
BY
INFECTIOUS
PARTICLE
DIAGNOSIS
(KOH/
histopath
exam) →
TISSUE FORM
CULTURE AT ROOM
TEMPERATURE
(Saboraud’s Agar)
At 37 Celsius (BHI)
Coccidioido
mycoses/
San
Joaquin
Valley fever
(found in
California,
an endemic
area)
PTB like with egg
shell cavity on x-ray
Disseminated
Meningitis: common
cause of death
Coccidiode
s immitis
Deuteromy
cete
(asexual
only)
-Thermally
dimorphic
-soil
saprophyte
Arthoconidia
- rectangular
shaped, thallic
conidiogeny
(conidia formed
inside hyphae)
-an asexual spore
which can be
disseminated by
fragmentation of
septate hyphae
and blastic yeast
cells
Hyphal fragments
produce
arthroconidia
Spherules
containing
endospores –
(not infectious)
Hyphae bearing
cylindrical, barrel-
shaped arthrocondia
separated by
dysjunctor cells
(empty degenerate
cells)
White floccose
colonies
No yeast-like colonies
on routine mycology
agar
Paracoccidi
oidomycosi
s
South
American
Blastomyco
sis/ Lutz-
Splendor-
Aleida’s
disease
a new
disease
PTB-like
Disseminated (oral
and nasal mucosa):
hepatosplenomegaly
is prominent
chronic
granulamatous lesion
or mulberry lesion
sometimes with
cervical adenitis
skin of face-most
common site of
infection
dimorphic and
pigmented
Paracoccid
ioides
braziliensis
Deuteromy
cete
(asexual
only)
-Thermally
dimorphic
- soil
saprophyte
Conidia Large, thin-
walled yeast
cells, with
multiple narrow
based buds
Septate hyphae with
no typical pattern
sporulation
Yeast cells with ship’s
or mariner;s wheel
appearance.
Penicilliosis
marneffei
produces
pigment
colonies
Pulmonary
disseminated (RES)
restricted to SEA
(Southeast Asia) –
Thailand (most
common in Chang
Mai areas)
Endemic – due to
mode of transmission
Opportunistic – they
affect
immunocompromised
px
naturally occurring
infections in bamboo
rats
new discovery
Penicillium
marneffei
-only
Penicillium
species
that is
thermally
dimorphic
– soil
saprophyte
Conidia Small, ovoid
yeast cells with
transverse
septum
Yeast cell
reproduction is
by tranverse
fission/
schizogony
Conidiophore
branch into metullae
which support the
phialides that bear
chains of conidia
Colonies produce
diffusible red
pigment → distinct
character of P.
marneffei (other
penicillium have
yellow pigment)
“Penicillus” –
paintbrush/fingerlik
e appearance
Round to oval cells
with crosswalls.
Opportunistic Mycoses
MYCOSES OCCUR AS INFECTIOUS
FORM
CAUSED BY DIAGNOSIS → TISSUE
FORM
CULTURE AT ROOM
TEMPERATURE
Candidiasis Yeast cells,
pseudohypha
e
Candida spp.
C. albicans (most
common)
Gram Stain/KOH/
histopath exam: small
budding yeast cells
and pseudohyphae
Germ Tube test:
Specific for C.
albicans
Pseudohyphae with
clusters of round
blastoconidia
Chlamydosores, yeast
cells and pseudohyphae
roduced on
chlasmydospore/cornme
al agar
9
MYCOSES OCCUR AS INFECTIOUS
FORM
CAUSED BY DIAGNOSIS → TISSUE
FORM
CULTURE AT ROOM
TEMPERATURE
Aspergillosis Allergic form – most
important
allergic bronchopulmonary
aspergilliosis
Asthmatic attack or hay
fever
Aspergilloma – “fungus
ball”
formation of intertwining
hyphal elements in
previous TB cavities.
Disseminated – invasive
aspergillosis
Conidia
Aspergillus spp.
A.fumigatus (most
common)
-soil saprophyte
-Monomorphic mold;
has a different sporing
head than penicillium
KOH/histopath exam
Wide, septated,
dichotomously
branced (acute angle)
hyphae - distinct
characteristics.
Conidiophore
supports swollen
vesicle covered by
phialides bearing
radial chains of
conidia
Sporing head with rows
of phialides bearing
conidiospores
Conidiospores arise from
“foot cell”
Cryptococcos
is
also called
Busse-
Buschke’s
disease or
torulosis
Pulmonary
(cryptococcoma)
-a solitary pulmonary
nodule in the mediastinum
mimicking a carcinoma.
Disseminated
-have a tendency for CNS
infection causing
meningitis.
Non-
capsulated
yeast cells
which is
smaller
because it
loses its
capsule.
Monomorphi
c yeast.
1. Cryptococcus
neoformans
(Filobasidiella
neoformans)
-in pigeon excreta
-affect the
immunocompromised
-Clinical disease:
Meningoencephatlitis
2 biotypes:
a. Cryptococcus
neoformans var.
neoformans.
→ Serotype D
b. Cryptococcus
neoformans var. grubii
Serotype A
2.Cryptococcus gatti
(Filobasidiella
bacillispora)
-soil under Eucalyptus
tree
→ Serotype: B,C
-affect the
immunocompetent
-Clinical disease:
pneumonia
India ink/histopath
exam
India ink-negative
stain (stains
background)
Yeast cells with wide
capsule.
Creamy, mucoid yeast
colonies.
Encapsulated yeast cells
Bird Seed agar (Niger) -
brown to black pigment
colonies due to melanin
protein due to
phenyloxidase produced
by the organism.
Chemical test: Urease
Test (+) – pink color
Caffeic Acid Test: (+) –
phenoloxidase
production
L-canavarine-glycine-
bromthymol blue (CBG
medium)
- C. neoformans
(yellow)
- C. gatti (blue)
Serologic test: antigen
detection - latex
agglutination & ELISA
Zygomycosis
/
Mucormycosi
s
- Rhinocerebral
- Pulmonary
- Cutaneous
- GIT
- Disseminated
Sporangiospo
re born
inside the
sporangium
Conidia – not
contained in
a
sporangium;
produced by
septate.
Filamentous fungi
belonging to
Phylum Zygomycota –
asexual
sporangiospores
Class Zygomycetes
(asexual and sexual
form)
Asexual → conidia
Sexual → zygospore
Genera:
1.Rhizopus
2.Mucor
3. Absidia
→ 1st 2 genera – more
common
KOH/histopath exam
Aseptate, wide
hyphae branching at
right angle.
Wide, ribbon like.
Morphologic features:
1. Rhizopus spp.
sporangia around
sporangiosphores
unbranched, nodal
columellae
hemispherical
no collarette
remains when
sporangia ruptures
rhizoids well
develop.
2. Mucor spp.
sporangia round
sporangiospores
branched,
internodal
no rhizoids
columellae round to
oval
3. Absidia spp.
sporangia pyriform
apophysis with
colarettes remain
when sporangia
ruptures
rhizoids
rudimentary.