MYCOLOGY Flashcards
is the branch of biology that deals with the study of fungi,
including their genetic and biochemical properties, their
taxonomy as well as pathogenesis and toxicity
Mycology
☐Eukaryotic microorganisms that occur ubiquitously in
nature in the domain Eucarya.
Fungi
Fungi
☐Eukaryotic microorganisms that occur ubiquitously in
nature in the domain____
Eucarya.
The kingdom fungi
(_____) has over 50,000 different species but only ____
have been identified as human pathogens.
Mycota; 200
Fill the fungi’s features below:
Diameter
Nucleus
Cytoplasm
Cell membrane
Cell wall content
Spores
Thermal dimorphism
Metabolism
Aprox. 4 nanogram (candida)
Eukaryotic
Mitochondria and endoplasmic reticulum present
Sterols present
Chitin
Sexual and asexual spores for reproduction
Yes (some)
Require organic carbon; no obligate anaerobes
Fungal Cell wall is composed
CHITIN
a polysaccharide composed of long chains of _____ and plenty of polysaccharides such as _____
Chitin; N-acetylglucosmine; β- glucan
☐β- glucan: a long polymer of
D- glucose
Medically important ( site of echinocandin action)
☐β- glucan
Fungal Cell membrane is composed of
ERGOSTEROL
the alternative in human cholesterol)
☐Ergosterol
☐Site of action of Ampothericin B and Azoles
☐Ergosterol
☐Ergosterol is the ☐Site of action of
Ampothericin B and Azoles
Two types of Fungi
Yeast
Molds
A single cell that reproduce through budding
YEAST
Grow as long filaments ( hyphae) and form a mat
(mycelium)
Molds
Molds: Grow as long filaments ( ____) and form a mat
(_____)
hyphae; mycelium
Some hyphae for Transverse walls (_____ hyphae);
others do not (_____ hyphae)
septate; nonseptate
The taxonomy of the fungi is essentially based on their?
morphology
The taxonomy of the fungi is essentially based on their
morphology.
☐Classifications:
☐Dermatophytes
☐Yeast
☐Molds
☐Dimorphic fungi
☐ causes infection of the keratinized tissues
☐Dermatophytes:
single cells
☐Yeast:
☐ grow in filamentous structures
☐Molds:
☐They exist as molds in the environment at ambient
temperature and as yeasts (or other structures) in
human tissues at body temperature
☐Dimorphic fungi:
Morphology OF FUNGI IS COMPOSED OF:
☐Hypha
☐Mycelium
☐Fungal thallus
☐Yeast
☐Dimorphism
this is the basic
element of filamentous
fungi with a branched,
tubular structure, 2–10
lm in width.
☐Hypha
this is the
web or matlike structure
of hyphae.
☐Mycelium
this is the entirety of the mycelia
Fungal thallus:
Fungal thallus and is also
called the
fungal body or colony
the basic element of the unicellular fungi.
Yeast:
Yeast: the basic element of the unicellular fungi. It is round
to oval and ____ in diameter.
3– 10 micrometer
Several elongated
yeast cells chained together and resembling true hyphae are
called
pseudohyphae
some fungal species can develop either the
yeast or the mycelium form depending on the environmental
conditions, a property called
dimorphism.
Dimorphic pathogenic fungi take the form of ____ cells
in the ____ stage and appear as _____ in the ____ stage
yeast; parasitic; mycelia; saprophytic
All fungi are
carbon heterotrophs
☐Dependent on exogenous nutrient substrates as sources of organic carbon, and with a few exceptions, fungi are obligate aerobes.
carbon heterotrophs
None of the fungi are
obligate anaerobes
Known Metabolic Types:
☐Thermophilic
☐Psychrophilic
☐Acidophilic
☐Halophilic
☐They reproduce
sexually by mating and
forming sexual spores
Sexual reproduction:
Sexual reproduction may commence as
☐Zygospores:
☐Ascospores:
☐Basidiospores:
Single
large spore with thick
walls
☐Zygospores:
Formed
in a sac called ascus
☐Ascospores:
☐Ascospores: Formed
in a sac called
ascus
____Formed externally on
the tip of the pedestal
called_____
☐Basidiospores:; basidium
Asexual reproduction may commence as
☐A. Arthrospore:
☐B. Chlamydospore:
☐C. Blastospores:
☐D. Sporangiospores:
☐Formation of conidia
(asexual spores) from
the sides or the ends of
specialized structures
Asexual reproduction:
_____arises
by fragmentation of the
ends of the hyphae(
mode of transmission
of ______)
☐A. Arthrospore; Coccidiodes immitis
rounded, thick-walled
and quite resistant.
☐B. Chlamydospore:
formed by
budding process of yeast
☐C. Blastospores:
☐Some yeast ( _____, can form
multiple buds that do not
detach, thus producing
sausage-like chains
called ______
C. albicans; pseudohyphae
______ formed
within a sac (sporangium) on
a stalk by molds such as
____&_____
☐D. Sporangiospores; Rhizopus and Mucor
Medical Mycoses according to site of infection:
☐Superficial mycoses
☐Cutaneous mycoses
☐Subcutaneous mycoses
☐Deep Mycoses
☐Systemic mycoses
☐Opportunistic mycoses
☐ Fungi that are able to cause systemic infection
☐ Fungi that are able to cause systemic infection
☐ Fungi that are able to cause systemic infection are ☐Primarily involve the _____ system
respiratory
☐Systemic infection caused by normal flora that become
opportunistic in immunocompromised patients
☐Opportunistic mycoses:
These are limited to the stratum
corneum and essentially elicit no
inflammation.
Superficial Mycoses
is a
common superficial mycosis,
which is characterized by
hypopigmentation or
hyperpigmentation of skin of the
neck, shoulders, chest, and
back.
Pityriasis versicolor
☐Pityriasis versicolor is due to____, ____, ____, which
involves only the superficial
keratin layer.
Malassezia furfur,
Malassezia globosa,
Malassezia restricta,
_____is a superficial
mycosis due to _____
which is manifested by a small
firm black nodule involving the
hair shaft.
Black piedra; Piedraia hortae
______due to
______ is
characterized by a
larger, softer and
yellowish nodules on
hair
White piedra; Trichosporon beigelii
______most
typically presents as a
brown to black silver
nitrate-like stain on the
palm of the hand or sole
of the foot and and is
caused by
______
Tinea nigra; Hortaea werneckii
☐caused by fungi (_____) that infect only superficial
keratinized structures (skin, hair, and nails), not deeper tissues.
dermatophytes
dermatophytes ☐Three important genera:
☐Microsporum:
☐Trichophyton:
☐Epidermophyton:
Infects hair and skin but not the nails
☐Microsporum:
Infects hair, skin and nails
☐Trichophyton:
Infects skin and nails but not the hair
☐Epidermophyton:
☐cutaneous infections due to other fungi, the most common of
which are ______ spp
Dermatomycoses; Candida
_____ affects the feet; ____
☐Tinea pedis; ☐Athelete’s foot
_____ affects
the fingernails and
toenails; ______
☐Tinea unguium; ☐Onchomycosis
_____affects the arms limbs and trunk; _____
☐Tinea corporis; ☐Ring worm
_____ affects the groin area; _____
☐Tinea cruris; ☐Jock itch
affects the hand and
palm area worse than
tinea pedis
☐Tinea manuum:
affects
the scalp
☐Tinea capitis:
____ affects the facial hair; ____
☐Tinea barbae; ☐Barber’s itch
____affects the face; ____
☐Tinea faciei; ☐Face fungus
☐These include a range of
different infections
characterized by infection
of the subcutaneous
tissues usually at the point
of traumatic inoculation
Subcutaneous Mycoses
☐An inflammatory response
develops in the
subcutaneous tissue
frequently with extension
into the epidermis.
Subcutaneous Mycoses
Subcutaneous Mycoses
Three general types:
☐Chromoblastomycosis
☐Mycetoma
☐Sporothricosis
Subcutaneous mycosis
characterized by
verrucoid lesions of the
skin (usually of the lower
extremities);
Chromoblastomycosis
Chromoblastomycosis Subcutaneous mycosis
characterized by
_____ of the
skin (usually of the lower
extremities);
verrucoid lesions
Histological examination
reveals muriform cells
(with perpendicular
septations) or so-called
“copper pennies” that are
characteristic of this
infection.
Chromoblastomycosis
Chromoblastomycosis Histological examination
reveals _____
(with perpendicular
septations) or so-called
“______” that are
characteristic of this
infection.
muriform cells; copper pennies
Generally limited to the
subcutaneous tissue with no
involvement of bone, tendon, or
muscle.
Chromoblastomycosis
☐The most common causes of
chromoblastomycosis:
☐Fonsecaea pedrosoi
☐ Pedroso’s disease
☐Fonsecaea compacta
☐ Fonseca’s disease
☐Cladophialophora carrionii,
☐ Cladosporiosis
☐Rhinocladeiella aquaspersa
☐Phialophora verrucosa.
_____ *A _____ and
______ subcutaneous
mycosis, which is destructive
of contiguous bone, tendon,
and skeletal muscle.
Mycetoma; suppurative; granulomatous
is characterized
by the presence of draining
sinus tracts from which small
but grossly visible pigmented
grains or granules are
extruded.
*Mycetoma
☐The causes of mycetoma
are more diverse but can be
classified as ____ and
_____ mycetoma.
eumycotic; actinomycotic
☐The most common agent:
☐ Eumycotic mycetoma
________________
☐Actinomycotic mycetoma
________________.
Pseudallescheria boydii
Nocardia brasiliensis
Mycetoma: ____ foot
Madura
Fungi causing mycetoma:
Dematiaceous (melanized) Fungi
Fungi causing mycetoma:
- Dematiaceous (melanized) Fungi
- Pigmented ______
- The melanin pigment is
deposited in the _____ of
these organisms.
These fungi may produce a
range of infections from
____to ______to
______ infection
characterized by the presence of
dematiaceous hyphal and/or
yeast-like cells in tissue.
brown to black.
cell wall
superficial ; subcutaneous ; deep (visceral)
deep infections due to
dematiaceous fungi are termed
phaeohyphomycosis
______☐This infection is due to
_______ and
involves the subcutaneous
tissue at the point of
traumatic inoculation.
Sporotrichosis; Sporothrix schenckii
☐The infection usually
spreads along cutaneous
lymphatic channels of the
extremity involved.
Sporotrichosis
The _____ pathogenic fungi are
able to establish infection in a
normal host
primary
The primary deep pathogens
usually gain access to the host
via the
respiratory tract.
The primary systemic fungal
pathogens include
A. Coccidioides immitis
B. Histoplasma capsulatum
C. Blastomyces dermatitidis
D. Paracoccidioides brasiliensis.
Coccidioidomycosis Known as the
“Valley Fever”
Coccidioidomycosis
Known as the “Valley Fever”
- The _______ of
Coccidioides immitis are
inhaled and convert in the
lung to _____.
- Most cases of are clinically
_____ or mild infections in
patients who inhale infective
arthroconidia.
- Some patients have
______
infection and also may suffer
dissemination to the brain,
bone, and other sites.
arthrococonidia; spherules
occult
progressive pulmonary
is a life-threatening infection of Coccidioidomycosis
requiring lifelong treatment.
Coccidioides meningitis
A primary pulmonary infection
resulting from inhalation of conidia
of Histoplasma capsulatum which
convert in vivo into the
blastoconidial (budding yeast) form
Histoplasmosis
Histoplasmosis
A primary pulmonary infection
resulting from inhalation of conidia
of ________ which
convert _____ into the
______ (budding yeast) form
Histoplasma capsulatum; in vivo; blastoconidial
Dissemination to the hilar and
mediastinal lymph nodes, spleen,
liver, bone marrow, and brain may
be life-threatening in infants and
other immunocompromised
patients. Common in AIDS
Histoplasmosis
Histoplasmosis (like ______)
is characterized by ______ of the pathogen in
macrophages and a
granulomatous reaction in tissue.
tuberculosis; intracellular
growth
☐Histoplasmosis also may be
associated with a chronic
inflammatory process known as
______, where
scar tissue (formed in response
to H. capsulatum) encroaches on
vital structures in the
mediastinum (mid chest area)
fibrosing mediastinitis
Similar to histoplasmosis, is a
primary pulmonary infection
resulting from inhalation of
conidia from the mycelial phase
of Blastomyces dermatitidis
which convert in vivo to the
parasitic yeast phase.
Blastomycosis
Blastomycosis
Similar to histoplasmosis, is a
primary pulmonary infection
resulting from inhalation of
conidia from the ______ phase
of _______
which convert in vivo to the
______ phase.
mycelial; Blastomyces dermatitidis; parasitic yeast
In the
______ phase also
causes a primary pulmonary
infection. This may cause
______
blastoconidial; chronic pneumonia
The organism elicits a
granulomatous reaction often
associated with a marked
fibrotic reaction.
Blastomycosis
spread of the fungi to the skin,
bones and prostate in male
Disseminated Blastomycosis:
causes paracoccidioidomycosis
☐Paracoccidioides brasiliensis
☐Paracoccidioides brasiliensis
causes
paracoccidioidomycosis
paracoccidioidomycosis ☐also known as
South American
blastomycosis.
Paracoccidiodes
A ______ that exists as a mold in ____ and as a yeast in _____. The yeast is thick-walled with multiple
buds, in contrast to ______, has a single bud
dimorphic fungus; soil; tissue; B. dermatitidis
☐This fungus grows in the soil and
is endemic in rural Latin America.
Disease occurs only in that
region.
Paracoccidiodes
Paracoccidioides:
yeasts with multiple buds
resembling a_____
Stain:_____
“ship captain’s wheel.”; Methenamine silver stain
Opportunistic fungi causing
______invade via the
respiratory tract, alimentary
tract, or intravascular devices.
deep mycosis
The opportunistic fungal
pathogens include:
Cryptococcus neoformans
Candida spp.
Aspergillus spp.
Penicillium marneffei
the Zygomycetes
Trichosporon beigelii
Fusarium oxysporum
is the most
common opportunistic fungal infection.
Candidiasis
is the most
common cause of candidiasis.
Candida albicans
may involve the epidermal and mucosal surfaces, including those of
the oral cavity, pharynx, esophagus, intestines, urinary bladder, and
vagina
A. Superficial candidiasis
The alimentary tract and intravascular catheters are the major
portals of entry
B. Deep (or visceral) candidiasis.
The kidneys, liver, spleen, brain, eyes, heart, and other tissues are
the major organ sites involved in_____
deep or visceral candidiasis.
The principal risk factors predisposing to deeply invasive
candidiasis are protracted courses of:
broad spectrum antibiotics,
cytotoxic chemotherapy, corticosteroids, and
vascular catheters.
most
frequently involves the lungs
and paranasal sinuses.
*Invasive aspergillosis
*The fungus, _____ may disseminate
from the lungs to involve the
brain, kidneys, liver, heart, and
bones.
Aspergillus
fumigatus
*The main portal of entry for
aspergillosis is the ______, however, injuries to the
skin may also introduce the
organism into susceptible hosts.
respiratory
tract
fungus ball that colonizes in a healed lung scar or abscess from a previous disease
Aspergilloma
Zygomycosis due to
_____, _____, ____, _____, species, or
other members of the class
of Zygomycetes, also
causes invasive
Sinopulmonary infections.
Rhizopus, Rhizomucor,
Absidia, Mucor
An especially life-threatening
form of zygomycosis (also
known as ______), is
known as the ______
syndrome, which occurs in
diabetics with ______,
this disease is highly lethal
Mucormycosis; rhinocerebral; ketoacidosis
Zygomycosis in the eyes
Periorbital mucormycosis
is an
encapsulated yeast that is
most typically an opportunistic
fungal infection that most
frequently causes pneumonia
and/or meningitis.
Cryptococcosis
most common
risk factor for Developing
cryptococcosis:
Defective cellular immunity/ acquired Immune deficiency syndrome
Cryptococcosis It is caused by
Cryptococcus
neoformans
is an
infection by brown to black
pigmented fungi of the
cutaneous, superficial, and
deep tissues, especially brain.
Phaeohyphomycosis
is an opportunistic fungal infection caused by any of
a variety of normally saprophytic fungi with hyaline hyphal elements.
Hyalohyphomycosis
Hyalohyphomycosis is an opportunistic fungal infection caused by any of
a variety of normally saprophytic fungi with_______
hyaline hyphal elements.
fungal agent with septate hyphae and nonpigmented (hyaline)
Hyalohyphomycosis
☐Traditionally, the _____&______ forms of
hyalohyphomycosis have been most commonly identified
disseminated and corneal
Fungal keratitis due to
Acremonium strictum
is the morphological and
physiological conversion of certain fungi from one
phenotype to another when such fungi change from
one environment to another.
Fungal dimorphism
Dimorphic fungi include:
and certain opportunistic fungi such as:
C immitis,
H capsulatum,
B dermatitidis,
P brasiliensis,
P marneffei, and
S schenckii,
Candida albicans
Penicillium marneffei.
Various environmental host factors control fungal
dimorphism. These factors include:
amino acids,
temperature,
carbohydrates, and
trace elements (e.g. zinc).
______ the morphological transformation is from a
hyphal form to a yeast-like form (or spherule in the case of
C immitis) in tissue
S. schenckii,
.the dimorphism of ______ is somewhat different
in that the organism transforms from a _____ yeast-like
structures (blastoconidia) to _____ structures known
as ______. Other filamentous structures may later
develop as _____ and _____.
Candida albicans; budding; filamentous; germ tubes; pseudohyphae; hyphae
is unique in being the only
Penicillium species pathogenic to humans.
Penicillium marneffei
