Block 5 Flashcards
Fungi overview
Is fungi widely distributed?
is fungi unicellular or multicellular?
is fungi eukaryatic?
sexual or a sexual reproducation?
Yes
both
yes
both
Fungi overview
what is eukaryotic?
organism that has a nucleus and produces spores
Fungi overview
Fungi is Hererotropic, what does that mean?
ingest or absorb organic carbon
Fungi overview
fungi is non-photosynthetic, what does that mean?
usually awrobic growth with an optimal tem of 25-37C
tolerable to a high osmotic pressure and asidic environment–they can surviv in salty or sour foods.
Fungi overview
Are all fungi saprophyes?
marjority of fungus is saprophytes (decayers) but can also be mutualistic symionts or parasites
typically opportunistic pathogens
Fungi overview
what is a fungal structure?
rigid cell wall (mannon, chitin, come cellulose, chitosan), nucleus, mitochondria, ribosomes, microtubules.
Fungi overview
what is chitin
provide rigidity, structural supposr and some protection
Fungi overview
what is ergosterol
is the dominand sterol (versus cholesterol in animals)
Fungi overview
do fungi cause disease in healthy animals?
what are predisposing factors?
rarely
immunosuppression (2nd fungal infections), prolonged antibiotic treatment, young or old, malnutrition, being in a place/are with a lot of fungal spores, damage tissue, persisitent moisture of skin, some nopplastic conditions
Fungi overview
classification?
- superficial or cutaneous mycoses: effects epidermis, keratinized areas like hair and nails, mucous membranes
- * subcutaneous mycosis: effects dermis, bone, muscle, fascia
- systemic mycoses: mainly respiratory and GI track, but can spread and effect other organs
Fungi overview
multicellular filaments with branching hyphae, can see Mycelium on
culture (filamentous mass of hyphae making the cloudy/fluffy like structures)
what is it?
mold
Fungi overview
4 kinds of molds?
* Vegetative mycelium: grows INSIDE the agar/substrate, provides support and absorbs
nutrients
* Reproductive mycelium: aerial hyphae differentiate to support fruiting bodies
* Aerial hyphae: vertical growing hyphae
* Septate hyphae:** dived a cell into compartments** with a septa (does NOT divide whole
cells)
Fungi overview
unicellular spheres, use a selective media for fungi when culturing,
reproduce by budding or budding/spore formation
what are they?
Yeasts
Fungi overview
changes between mold and yeast based on temperature, CO2,
concentration, and pH
what is it?
Dimorphic fungi
Fungi overview
Dimorphic fungi
what relevance is temperature?
- Mycelial form at room temp and yeast at 37oC (or in tissue of animals)
- A lot of pathogenic fungi are dimorphic
Fungi overview
what is mycosis?
what is mycotoxicosis?
tissue invasion
toxin production
*both make spores
*hypersensitivity is key
Fungi overview
mostly see this type reproduction as it is very
effective, can happen a few different ways
what is it?
Asexual reproduction
Fungi overview
Asexual reproduction: what 4 ways?
* Fission: somatic cell division of nuclei by mitosis
* Budding: cell wall bulges out, daughter nucleus migrates into the bud, the
bud will then separate off
* Fragmentation of hyphae: each hyphae that separates will become a
new organism
* Sporulation: followed by germination of spores
Fungi overview
Asexual reproduction Sporulation:
when are spores produces and what are the 2 main types?
- Spores are produced my mitosis and there are 2 main types
* Sporangiospores: formed within a sac-like structure called a sporangium
*** Conidia: **formed on conidiophores
Fungi overview
rare, pos. versus neg., fusion(key word) of 2 haploid nuclei
followed by meiotic division of the diploid nucleus
what is it?
Sexual reproduction:
Fungi overview
what benefit is sexual reproduction?
- Benefit: enrichment of fused together genetic material
Fungi overview
What is this
Arthrospores
chlamydospores
sporangiospores
conidiospores
blastospores
what is this
phialospores
what is this
arthrospores
what is this?
no idea slide doesn’t say
what is this
no idea slide doesn’t say
what is this?
microconidia
what is this?
macroconidia
what is this?
a and b-Macrodium -the one with lots of little sausage links
top of a and bottom of c- microconidium- the one with one little bulge
what is this
microsporum spp
*macroconidia
**ring worm
what is this
trichohyton
Dermatophytoses overview
Cutaneous mycoses
classification? (3)
* Superficial or cutaneous mycoses: effects epidermis, keratinized areas like hair and nails, mucous membranes
* Subcutaneous mycoses: effects deep layers such as dermis, bone, muscle, fascia
* **Systemic mycoses: **mainly respiratory and GI tract, but can spread and effect other organs
Dermatophytoses overview
Cutaneous mycoses
not to be confused with dermatophilus, what is: An infection of keratinized tissues (hair, feathers, outside layers of skin, nails, claws, horns) caused by a
dermatophyte, the infectious form is arthrospores, zoonotic
Dermatophytoses
Dermatophytoses overview
Cutaneous mycoses
what is geophilic dermatophyte:
live and replicate in soil, especially where there is decomposing keratinous material
Dermatophytoses overview
Cutaneous mycoses
what is Zoophilic dermatophyte:
obligate animal pathogens and host specific
Dermatophytoses overview
what is invade hair and skin, thick-walled multiseptated macroconidia that are stalked and arranged singly along hypae
who gets it?
Microsporum: invade hair and skin, thick-walled multiseptated macroconidia that are stalked and arranged singly along the hyphae
* M. canis, M. gypseum, M. nanum, M. gallinae
* M. canis: the most common dermatophyte of domestic animals (what we typically see in clinics)
Dermatophytoses overview
what is: target keratinized tissue (hair, skin, nails, horns, claws), thin-walled macroconidia that are
cylindrical or cigar shaped, produced in small numbers
* M. mentagrophytes, T. equinum, T. verrucosum
Trichophyton
Dermatophytoses overview
what is Epidermophyton
no idea slide doesn’t say
Dermatophytoses
How transmitted?
Transmission: direct contact with an infected animal, by exposure of
arthrospores from the environment or fomites
Dermatophytoses overview
what are arthrospores
Arthrospores: shed by infected animals, they can remain viable in the environment for
years
Dermatophytoses
Pathogenesis?
Pathogenesis: dermatophyte spores invade skin abrasions and enter into the
stratum corneum (top layer of skin), release keratinase, protease, and elastase
to break down keratin proteins which results in an inflammatory reaction
(redness, swelling, heat, alopecia)
* Once the inflammatory reaction has occurred, fungal growth will stop and move
away from the site of infection and on to the next hair follicle which results in the
classical ring shaped lesion
Dermatophytoses
CS?
alopecia, erythema, scaling, crusting, annular-ringed lesions, vesicle or
papules
* Due to inflammation, Trichophyton infections are more severe than Microsporum
infections
Dermatophytosis infections
Cutaneous mycoses
Canine ringworm
T or M which is more virulent?
is it zoonotic?
M. gypseum is associated with?
T. erinaceid is associated with?
T. mentagrophytes is associated with?
what is kerion?
what about lesions?
- Remember: T is more virulent than M
- M. canis: most commonly seen in small animal
clinics, zoonotic - M. gypseum: associated with digging
- T. erinaceid: contact with hedgehogs
- T. mentagrophytes: catching rats
-
Kerion: intense inflammation with swelling, ulceration
and purulent exudate - Lesions: brittle hair, dry/scaly skin, crust, scabs
Dermatophytosis infections
Feline ringworm
cats re teh primary reservoir of ?
what is feline otitis?
most common in what kind of cats?
what is the CS?
is this a problem?
what about lesions?
- Cats are the primary reservoir of M. canis
- Feline otitis: expressed as a persistent waxy
discharge - Most common to appear on kittens (immature
immune system) or adults with immune deficiency - CS: usually asymptomatic
- Public health risk!
- Lesions: circular areas of stubbed hair, alopecia,
mild scaling, folliculitis - Usually seen on the head/face
Dermatophytosis infections
Bovine ringworm
what is the name?
what is the optimal temp?
who gets it?
when do they get it?
what about lesions?
what about recovery?
prevention?
is it zoonitic?
Bovine ringworm
* Trichophyton verrucosum
* Optimal temp is **37oC **for growth
* Calves are more susceptible
* Higher incidence in the winter due to cattle being
housed in close contact
* Lesions: circular, scattered, skin scaling, alopecia,
large plaques of thick scabs/crust may develop
* Severe inflammation and puritis
* Usually seen around the eyes first
* Spontaneous recovery will occur
* Prevention: vaccinate!!!
* Zoonotic!
Dermatophytosis infections
Porcine ringworm
what is the primarily seen infection?
who gets it?
predisposing factors?
what about lesions?
- Primarily see infection by M. nanum, but can also
get infections from M. gypseum, M. canis, T.
mentagrophytes - Common disease affecting market pigs
- Predisposing factors: crowding or high density,
humidity, poor sanitation and management - Lesions: circular and rough, mildly inflamed
- Can be seen anywhere on the body
- **Economic loss
**
Dermatophytosis infections
Equine ringworm
name?
what about lesions?
cause?
- T. equinum or M. gypseum
- Lesions: multiple, dry and scaly raised lesions,
matted hair due to inflammation and exudates
that can clump together and appear moth eaten - Lesions can be all over the body
- Infections often become chronic or subclinical,
and reoccur under stress
Dermatophytosis infections
Avian ringworm
aka?
what about lesions?
- AKA: Favus or White comb
- M. gallinae
- Lesions: white patches on the combs of male
birds, sometimes the infection will extend into the
feathers
Dermatophytoses Dx, Tx, control
what 4 ways can you Dx?
- Woods lamp
- Microscopic examination
- Culturing
- Physiological tests
Dermatophytoses Dx, Tx, control
With a Woods lamp how accurate is it? what happens?
Woods lamp: will fluoresce green when fungi is present (50-60%), shine light over lesions to make the best choice when selecting an area to sample from
* Remember: no illumination does not necessarily mean there is no infection!!!
Dermatophytoses Dx, Tx, control
Microscopic examination: what is the process?
Microscopic examination: look for hyaline septate hyphae on scale and hair shafts, or arthroconidia on hair
Dermatophytoses Dx, Tx, control
Culturing:
what is the process?
what is Dermatophytes test medium (DTM)?
How does it work?
Culturing: cleanse lesion with alcohol to reduce bacterial contamination, clip hair if needed, scrape skin and pluck hair from the PERIPHERY of the lesion
* Dermatophytes test medium (DTM): Sabouraud’s dextrose sugar with peptones, antibiotics, cyclohexamine and phenol red pH indicator,
incubated at 25o-35oC (unless T. verrucosum then optimal temp is 37oC)
* If red BEFORE 10 days: dermatophyte
* If yellow, and then red AFTER 10 days: non-dermatophyte
* M. canis culture: spreads across the agar plate, **white **cottony surface growth with a golden-yellow reverse pigment
Dermatophytoses Dx, Tx, control
Physiological tests:
what is the process?
Physiological tests: temp. tolerance, urease production, in vitro hair perforation test for Trichophyton spp. (develop few microconidia)
Dermatophytoses Dx, Tx, control
Tx
what 2 ways and how long do you treat?
1-Removal and/or killing: clipping, shampoos, dips, sprays, topicals
2-Systemic: Griseofulvin, Azole-Ketoconazole, Terbinafine
* Treat until there are 3 negative cultures
Dermatophytoses Dx, Tx, control
Prevention & control:
How?
Prevention & control: clean up environment (vacuum, wash bedding, disinfect collars/leashes/tack/brushes/clippers)
* Use 10% bleach solution
*wear gloves
Dermatomytoses Infections
what is a member of the normal skin microbiota and an opportunistic yeast pathogen
* M. fufur, M. pachydermatis, M. sympodialis, M. globose, M. obtuse, M. resticta, M. dermatis, M. nana, M. sloofiae
Malassezia
Dermatomytoses Infections
what are the predisposing factors?
Predisposing factors: humidity, waxy ears, hairy/pendulous ears, neoplasm, allergies, change in sebum,
recent antibiotic or steroid therapy, trauma
Dermatomytoses Infections
Otitis externa- M. pachydermatis:
CS?
Dx?
Tx?
- CS: head shaking, puritis, odorous, pain
- Dx: not very zoonotic
- Otoscope exam of the ear canal
- Cytological exam for bacteria/yeast/mites
- Tx: M. pachydermatis infection is always
secondary, so treat the underlying cause! - Topicals antifungals, systemic antimicrobials
Dermatomytoses Infections
Seborrheic dermatitis- M. pachydermatis
what is it?
who gets it?
predisposing factors?
CS?
Dx?
Tx?
-
Superficial deramitits
* Breed disposition: poodles, cocker spaniels, chihuahuas, German
shepherds, boxers, bassets - Predisposing factors: allergies, seborrhea
-
CS: face rubbing, foot licking, erythematous and scaly skin, alopecia,
hyperpigmentation, lichenification (leathery skin) - Dx: history of poor AB response, looks for yeast cells on skin scaping
- **Tx: **remove predisposing factors, shampoo, creams/dips, topical or
oral ketoconazole
Dermatomytoses Infections
Trichosporon spp.
what is it?
who gets it?
how do you treat it?
- Nasal mass in cats
- Can occlude the nares and will need surgically
removed - Follow up treatment with parenteral administration
of ketoconazole
Dermatomytoses Infections
Geotrichum candidum
what is it?
where is it found?
who gets it and what happens?
what relevance is Geotrichosis? hint what type of animal and when they get it what does it look like?
- Saprophyte: found in the soil or decaying matter
- Can be isolated from the feces of a normal
healthy animal - Can cause diarrhea in dogs and apes on
occasion - **Geotrichosis: retiles and amphibians
** - Cutaneous lesions, nodular, circumscribed, dermo-
epidermal masses
Subcutaneous mycoses
Classification: what are the 3 classifications?
- Superficial or cutaneous mycoses
- Systemic mycoses
- Systemic mycoses
Subcutaneous mycoses
Classification:
what type effects epidermis, keratinized areas like hair and nails, mucous membranes
Superficial or cutaneous mycoses
Subcutaneous mycoses
Classification:
what type effects deep layers such as dermis, bone, muscle, fascia
Subcutaneous mycoses
Subcutaneous mycoses
Classification:
what type mainly respiratory and GI tract, but can spread and effect other organs
Systemic mycoses
Subcutaneous mycoses
This group is composed of what 2 things?
where are they found?
what do they look like?
This group is composed of dematiaceous or hyaline molds and dimorphic fungi, and they are found in soil
or decaying vegetation
* Dematiaceous: brown pigment
* Hyaline: colorless
Subcutaneous mycoses
Infections are typically associated with what?
how do they present?
how do they contract and spread?
How does this affect the time to develop and severity?
Infections are typically associated with **injuries or traumatized tissues **and are chronic and insidious
* Organisms establish on the skin/wound, cause a localized infection and spread to the LN’s
* AKA they take more time to develop and they are more severe
Subcutaneous mycoses
what are they often confused with?
how can you distinguish?
Can easily be confused with bacterial infections based on the skin lesions, BUT
* Bacteria should respond to antibiotic treatment and the fungi will not
Sporotrichosis
what is a dimorphic (changes shape with temp), dematiaceous (brown) fungus that is
found world wide, but most common in tropical and sub-tropical areas
Sporothrix schenckii
Sporotrichosis
how do you distinguish between molds and yeasts?
- Yeast: animal, 37oC, cigar shaped, pleomorphic budding yeast cells
- Mold: **environment, 25oC, **thin septate hyphae with tapering conidiophores bearing conidia in rosette like clusters
Sporotrichosis
where does it come from and what animals are affected?
S. Shenckii can be isolated from soil, vegetation, peat moss and wood and susceptible species include
dogs, cats, horses, humans, etc.
Sporotrichosis
What are the Virulence factors?
Virulence factors: thermotolerant, acid phosphatase, proteinase I and II, adhesion (T.A.P.P.A)