Microbio lecture 1-6

Hyphal fragmentation

Budding yeast cells

Chlamydoconidia

Macroconidia

Microconidia

Phialoconidia

Phialoconidia

Sporangiospores

A. Conidia

B. Phialide

C. Vesicle

How is Arthroconidia formed?

Hyphal fragmentation

How is Blastoconidia formed?

Budding

How is Chlamydoconidia formed?

Thick-walled differentiated cells

How is Macroconidia formed?

Is it multicellular or unicellular

Large conidia, multicellular

How is Microconidia formed?

Is it multicellular or unicellular

Small conidia, unicellular

How is Phialoconidia formed?

Produced by Phialides

How are Sporangiospores formed?

Produced inside a sporangium.

How do prokaryotic cells replicate?

Binary fission

Do antibiotics work on viruses?

Are viruses Motile?

No

Do viruses have nucleus?

Do viruses have metabolism of their own?

No

Mould, Bacteria, Virus, Yeast

Sequence them from the largest to smallest

Mould, Yeast, Bacteria, Virus

Describe resident microbiota

relatively stable commnities associated with a body site

Describe transient microbiota

microorganisms temporarily present

Primary pathogens, Pathobionts, Commensal microorganisms, Opportunistic pathogens

Sequence from the least to the most severe

Commensal microorganisms, pathobionts, opportunistic pathogens, primary pathogens

Describe eubiosis

a balanced and functional microbial community associated with a healthy host

Describe dysbiosis

a disruption or alteration of the composition and/or the function of the microbial community

Disk diffusion

measurement of inhibition zones

Broth dilution

determination of minimum inhibitory concentration (MIC)

Sexual and Asexual reproduction of Zygomycota

Sexual: Zygospores

Asexual: Sporangiospores

Sexual and Asexual reproduction of Basidiomycota

Sexual: Basidiospores

Asexual: rare

Sexual and Asexual reproduction of Ascomycota

Sexual: Ascospores

Asexual: Conidia

Moulds

Yeasts

What is fungal cell wall made of

Chitin, Glucans, Mannoproteins

What does the fungal cell membrane contain?

Ergosterol

Moulds

multi/unicellular

reproduction by ____

composed of ____ forming ___

muticellular

reproduction by spores

composed of hyphae forming a mycelium

Yeasts

multi/unicellular

reproduction by__

cell wall contains___

unicellular

reproduce by budding/fission

cell wall contains glucans, mannans and chitin

A. Aerial hyphae

B. Mycelium

Aspergillus, Penicillium,Saccharomyces what type of fungi phylum

Ascopores

Cryptococcus, mushrooms what type of fungi phylum

Basiodiospores

Rhizopus, Mucor what type of fungi phylum

Zygospores

Yeast are multi/unicellular

Unicellular fungi

Superficial mycoses

Epidermis, keratinized structures, mucous membranes lesions

Subcutaneous mycoses

subcutaneuous tissue lesions

systemis mycoses

respiratory and digestive tracts and other organ systems lesions

group of diseases resulting from the ingestion of fungal toxins which have been in food. name?

mycotoxicoses

secondary metabolities produced by fungi that are capable of causing disease and death in humans and other animals

mycotoxins

staining method

Lactophenol blue

Gram staining

Indian ink

Fungal spores and antigens must trigger hypersensitivity reactions with tissue invasion. T/F

F

Fungal diseases, clincal signs result from

A) exaggerated immune response

B) fungal growth in tissues

A

Repeated exposure of fungal diseases will lead to chronic respiratory disease T/F

T

Samples for specimen diagnosis should be collected from the active margin of fungal lesions. T/F

T

Biosafety cabin —> risk of human infection from spore aerosols

1. A dermatophyte test medium used for the isolation of dermatophytes. T/F

2. A dermatophyte test medium contains antibiotics that inhibit bacterial contaminants and many saprophytic fungi. T/F

3. A dermatophyte growth is typically associated with a colour change of the medium from red to yellow. T/F

4. A dermatophyte growth is associated with a colour change due to acidic metabolic products. T/F

5. Positive cultures cannot be confirmed by microscopic examination and colony morphology. T/F

1. T

2. T

3. F

4. F

5. F

Treatment for fungi involves targeting Ergosterol, from the plasma membrane of the fungi. T/F

T

Dermatophytes are a member of the phylum of

A. Basidiomycota

B. Ascomycota

C. Zygomycota

B

1. Dermatophytes are anaerobic. T/F

2. Dermatophytes are septate fungi. T/F

1. F

2. F

Lesion development of dermatophytes is influenced by virulence of the dermatophte, immunological competence of spores facilitated by the host. T/F

T

For dermatophytes, affinity for keratinized structures, inactive arthrospores (arthroconidia) adhere to keratinized structures and germinate. T/F

T

For dermatophytes, after tissue invasion by arthrospores, hyphae grow centrifugally from the lesion towards normal. T/F

Metabolic products of arthrospores produces local inflammatory response which is met by cell-mediated response. T/F

Both T

Infection and germination of Dermatophytes can be cause by

Minor trauma, bites from arthropods, damp skin surfaces, warmth

Wood’s lamp can be carried with suspicious dermatophyte lesions in cats and dogs, what colour will be found

Apple-green fluorescence

Dermatophytes laboratory recognition, what microscopic appearance will be found, and by what staining.

Macroconidia, lactophenol blue staining

Dermatophytes recognition

Microsporum Canis

Dermatophytes recognition

Microsporum gypseum

Dermatophytes recognition

Microsporum nanum

Dermatophytes recognition

Trichophyton mentagrophytes

Dermatophytes recognition

Trichophyton verrucosum

Isolation on Dermatophytes selective agar

Growth of Dermatohytes result in ____ metabolic products and the medium colour changes to ___

alkaline, red

Isolation of Dermatophyte test medium

Other contaminating fungi might also induce a colour change, other fungal media should be also considered. T/F

T

Treatment of scrapings of dermatophytes with ____ and the observation of arthrospores

KOH (potassium hydroxide)

Dermatophytes PAS technique

Histological sections of skin is unable to be stained by PAS technique to demonstrate fungal structures. T/F

F

Aspergillus spp. is a member of which phylum

Ascomycota

Aspergillus spp.

1. They are ubiquitous, saprophytic moulds with septate hyaline hyphae. T/F

2. They grow slowly by unpigmented colonies. T/F

3. They form conidia from phialides. T/F

4. They are acquired by the contact of spores on the skin. T/F

1. T

2. F

3. T

4. F

Sporing heads of Aspergillus

A. Conidia

B. Phialide

C. Vesicle

The pathogenesis of Aspergillus involves the spore inhalation, causes respiratory mitosis, affects the terminal parts of the ___ ___ and the production of extracellular enzymes that inhibits the activity of ___ and ____ by macrophages.

Bronchial tree

cilia

phagocytosis

Aspergillus spp. explain competent immune respone

1. Localized infection:

2. Granulomatous response:

1. confined to the respiratory tract

2. the host successfully controls the fungus via phagocytosis, forming mycotic granulomas to sequester the hyphae

Aspergillus spp. explain compromised immune response

1. Angioinvasion:

2. Thrombosis and infarction:

3. Dissemination:

1. hyphae undergo rapid elongation and invade blood vessel walls

2. invasion triggers severe vasculitis, thrombus formation and necrosis

3. fungus enters the systemic circulation (hematogenous dissemination) and produces multiple secondary fungal foci

Guttural pouch mycosis affects which animal

Horses

How does Guttural pouch mycosis affect the animal?

Fungal hyphae penetration into deeper tissues —→ tissue necrosis, thrombosis

What are the clinical signs of Aspergillus spp.

Epistaxis, dysphagia and laryngeal hemiplegia

Diagnosis for Guttural pouch mycosis

Clinical signs, endoscopic examination (nasal cavity and guttural pouch), X-ray

Diagnosis for guttural pouch disease what staining method?

Methenamine silver/PAS may reveal hyphal invasion

Whats the diagnosis for Guttural pouch mycosis

Isolation on SDA/PDA and lactophenol blue staining

PCR, serological tests

Yeasts are eukaryotic/prokaryotic, multicellular/unicelullar budding cells

Eukaryotic, unicellular

The asexual reproduction of yeast is by

blastoconidia

Can yeast form hyphae?

Yes

Teleomorph of yeast belong to the phylum ___ or ___

Basidiomycota, Ascomycota

Candida albicans grow at 37 degree celsius

____ produced on cornmeal agar, it is resistant to _____.

Its opportunistic infections are related to ____ in animals and humans.

Chlamydospores

cycloheximide

immunosuppression

Cryptococcus neoformans produced by large ____ , grow at 37 degree celsius producing ____.

Teleomorph is a _____

____ infection derived from environmental sources.

____ or sometimes desseminated disease in cats, dogs, horses and cattle.

Mucopolysaccharide

Mucoid colonies

Basidiomycyte

Opportunistic

Localized granulomas

Hyphae is the common characteristic of yeast/mould

Mould

Malassezia pachydermatis

Bottle-shaped cells

____polar budding

On the ____ of mammals and birds

Associated with canine seborrhoeic dermatitis and otitis externa

Associated with ___ which alter the microclimate of skin

Monopolar budding

Skin

immunosupression

Yeast. Localised mucocutaneous form of Candida (albicans)

Oral cavity, Gastrointestinal tract, Urogenital tract

Yeast virulence factors Candida (albicans)

Surface integrin-like molecules -

Surface structures -

Proteases and phospholipases -

Surface integrin-like molecules - allow adhesion to matrix proteins

Surface structures - bind fibrinogen and complement components

Proteases and phospholipases - aid tissue invasion

Yeast virulence factors Candida (albicans)

Phenotypic switching and biofilm

Hyphal forms

Phospholipase

Phenotypic switching and biofilm - host defence mechanism

Hyphal forms - cells convert to hyphal form to facilitate tissue penetration

Phospholipases - enhance invasiveness

Candida albicans

Blastoconidia

Candida albicans

Blastoconidia

Candida Albicans

Chlamydospores

Cryptococcus (neoformans) pathogenesis

Dropping of pegions, inhalation, yeast cells trapped in nasal cavities and lungs