Mycology 1

What is independent cells propagate by budding out similar cells from their surface which may or may not detach?

yeast

T/F Yeast is multi-cellular

Fasle, single cell

Multicellular tubular structures is known as what?

Hyphae

Which form of Hyphae is divided by cross walls?

septate hyphae

Which form of hypahe lacks cross walls?

Non-septate hyphae

What is multicellular filamentous structures formed by a mass of hyphae?

Mycelium

What is the common name for Mycelium?

Mold

Hyphae may or may not contain cross walls called ___

septa

How do molds increase in length?

Increase in length by apical growth

Mold identification may be made by the morphology of their ____ ____

reproductive structures

T/F Some molds are ubiquitous in environment

True

Mass of ____ produce colonies usually moist or mucoid they are composed of loose arrangement of _____ cells.

yeast

budding

Yeast is ___cellular and reproduction occurs by ____

unicellular

budding

T/F Yeast is ubiquitous in the environment and live as normal inhabitants in and on animals and humans

True

What are the THREE barriers in normal skin?

Chemical, Physical, and Immune barriers

What are the GI barriers? (6)

Mucus

•High saccharides

•pH: pH7

•Microbiome

•Enterocytes

•M cells

What are the TWO major mammalian barriers?

temp & redox potential

What temperature is it that many fungal organisms can not grow at?

37 C

What is it when enzymes more efficient at redox potential of non-living substrates?

Saprophytic

What is critical to host resistance?

T cell response

Fungi attempt to survive and grow in the host by using the following mechanisms: (11, i am sorry, just read this)

•Adhere to host cells via cell wall glycoproteins

•Capsule production

•Cytokine production suppresses complement

•Iron adsorption

•Production of keratinase, elastase, collagenase

•Survival within phagocytes

•Mycotoxins

•Surface hydrophobicity

•Unique enzymatic activity

•Thermal dimorphism

•Block cell-mediated immune defenses

Outcome of fungal infections can be dependent on what? (2)

•Host Factors (Host immune status, Genetics)

•Inoculum

What is the severity of a fungal infection dependent upon?

immune status of host

Infected host becomes nutritional source, what does this lead to?

tissue damage

____ ____ may result in necrosis, suppurative lesions - lack of host response associated w/ more severe

Opportunistic infections

____ ____ is usual in competent host - walls off & isolates the living fungus results in very little tissue death

Granuloma formation

T/F Granuloma formation can affect the lungs

True

Fungal infections are typically (easy/difficult) to treat

difficult

T/F Organisms are eukaryotic & use many of the same pathways as our own cells so that can cause some toxic effects

True

What is THREE disadvantages for treatment consideration?

•Economic considerations due to cost

•Relapse occurs often

•Stress resulting from repeated drug administration (length of time-months)

Why is it critical to get a diagnosis asap?

Success of treatment often associated with having an accurate ID prior to treatment

What plays a major role in animal exposure?

environment

Are indoor or outdoor animals are more likely to have fugal infection?

outdoor

What are some examples of environmental sources where you fill find pathogenic organisms?

•Storage of mulch, potting material, compost and other organic rich materials

What type of fungal infection infections of the outermost layers of the skin and hair and

occasionally extend deeper into the epidermis as well as nail?

Cutaneous Mycoses

What is important to predict potential pathogens causing disease?

Location

What are some different locations for cutaneous mycoses?

superficial, hair follicles, deep dermis, subcutis, or vascular tropism

_____: must be present when the conditions are such that disease can be initiatedns are such that disease can be initiated

Opportunistic

Where are Monomorphic Yeasts found?

found on humans and warm-blooded animals and in the environments they inhabit

T/F Opportunist that increases in numbers & invasive when normal bacterial flora is disturbed.

True

What yeast is a commensal yeast and parasitism associated with elevated counts

Malassezia pachydermatis

What breeds are commonly going to get Malassezia pachydermatis? (4)

Basset Hounds

Cocker Spaniels, Poodles

West Highland White Terriers

(Dogs w/ excessive sebum production or excessive folds)

Where is Malasseziasis found in the body?

Chin, lips, skin folds, ears, interdigital

What are some clinical features for dermatitis seen with Malasseziasis? (i am sorry) (7)

•Alopecia

•Erythema

•Scales

•Thickened skin and hyperpigmentation

•Moist or greasy, malodorous

•Moderate to severe pruritus

•Interdigital spaces, ventral neck, axillae, perineal region, external ear canal, skin folds

What are some clinical features that for •Otitis with Malasseziasis? (3)

•Malodorous

•Discharge

•Pruritus

What should you suspect with inflammatory skin diseases characterized by erythmatous and/or greasy lesions. Esp in areas with skin folds?

Malasseziasis

What is erythematous external ear w/ yellow or brownish discharge. Stenosis common in chronic cases?

Otitis externa (Malasseziasis)

What are SIX predisposing factors for Malasseziasis?

1. atrophy

2. fleabite hypersensitivity

3. •Primary and secondary cornification defects

4. skin folds

5. endocrine disorder

6. climate

Malasseziasis organism adheres to ____ ____ cells

stratum corneum

T/F Malassezia Diagnosis requires culture

False, it does not

Describe how to do the tape prep for Malassezia. (5 steps)

•Ultra-transparent clear adhesive tape

•Drop of Diff-Quik is placed on a glass slide

•Firmly apply the tape to the skin (repeatedly), remove it, apply tape to the glass slide with Diff Quik

•Examine under oil immersion (100X) to identify yeast organisms

•Look for peanut shapes

What must you do for Malasseziasis therapy?

Must identify other infectious agents, ongoing disease, or other predisposing factors

What are THREE topical agents that you can use to treat Malasseziasis?

Miconazole

Clotrimazole

Nystatin

What are TWO examples of systemic treatment of Malasseziasis?

Ketoconazole

Itraconazole

____ _____ is the most common

species isolated from man and animals

Candida albicans

Candidiasis is a switch pathogen, what does this cause?

disruption of host defenses & expression of virulence factors by yeast.

What candidiasis occurs when adhered to mucosal surfaces, biofilm production or tissue invasion

Filamentous esp

____ in urine indicates kidney is infected

Pseudohyphae

What are the SIX predisposing factors that can cause Candidiasis?

•Prolonged or excessive antimicrobial therapy

•Immunosuppressive therapeutics

•Debilitating disease or immunosuppression

•Trauma, surgery, indwelling catheters

•Stress

•Unsanitary conditions

What is one of the major animal species that is associated with candidias?

birds

What are the clinial features of Avian candidiiasis?

1 or 2 damaged esophageal mucosa or slowed crop emptying time see thickened mucosa w/ whitish pseudomembranes.

What are the THREE major forms of Candidiasis?

Cutaneous/UTI

GI overgrowth

Disseminated

What form of Candidiasis is ulcerative and exudative lesionInfection of mucous membranes?

Cutaneous

What form of Candidiasis is secondary to excessive antimicrobial usage or concurrent disease?

What is an example?

GI overgrowth

crop mycosis

What form of Candidiasis is an extension of primary infection?

What may diagnosis require?

Disseminated

blood culture

Candidiasis Microscopic Examination

Stain with Diff-Quick or Gramstain

Examine under ____ ( ___X)

____-based budding yeast

Presence of pseudohyphaeindicate invasion

oil

100X

Narrow

When you do a culture of Candidiasis what is the bacteria that is isolated? Does it confirm diagnosis?

Candida spp

No

What are the topical therapy for Candidiasis?

What are TWO examples?

Nystatin

Miconazole

Clotrimazole

What are the systemic forms of therapy?

What are TWO examples

Ketoconazole

Itraconazole

Fluconazole

What shape may you describe yeast as?

peanut