Decomposers, the best in the environment.

They break down organic material for a benefit, they need the organic molecules to survive and use them for their individual benefit.

Very diverse eukaryotic organisms.

Can be unicellular or multicellular.

Ex: Spores of Candida Albicans (uni)

*Present as normal floura on our skin and mucous membranes. We normally see infection candida.

Ex: Almanita Muscaria

*A red, poisonous mushroom (multi)

Ergosterol.

Important for targeting fungi specifically even though they are eukaryotic.

When combined with protein forms 'mannoprotein'.

They are immunogenic, meaning they induce an immune respons. We detect the fungal organism on the basis of that.

Often used to sero-group the fungal pathogens specifically.

Composed of long, unbranched chains of poly-N-acetylglucosamine.

Inert and rigid, giving the toughness of fungal organisms.

Makes fungi ubiquitious, so they can survive in adverse environmental conditions.

Offers support and integrity to the fungi.

Polymer of glucosyls made up of carbohydrates.

Provides structural integrity.

Very diverse.

Heterotrophs: rely on carbon (from glucose), nitrogen (from organic nirogen and ammonia), nucleic acid.

All of these resources have to be provided for externally. Aerobes and facultative anaeurobes (anaerobic if needed). NO FUNGI ARE STRICTLY ANAEROBES

They secrete enzymes outside of the body (exo-enzymes) to break down complex molecules to simpler form and then they acquire ita nd utilize it for their metabolism.

Note: Fungi lack photosynthetic energy producing mechanisms.

Grow at various temperatures

(Low --> High: Psychrophilic, Mesophilic, Thermophilic)

Wide range of pH: 2.2 - 8.5

(clinically important fungi at 6.5-7.0)

80-90% humidity

Prefer the dark (photosensitive)

Aeriation: Aerobes and facultative anaerobes

Take on the shape of yeast and/or mold.

At ambient temperature, they are mold (hypha).

When they enter the body they change shape to assume circular/elliptical shape of yeast.

We must know the dimorphic fungi. They are...

(YOU WILL BE TESTED ON THIS)

"Body Heat Changes Primary Shape"

B: Blastomyces dermatidis

H: Histoplasma capsulatum

C: Coccidioides immitis

P: Paracoccidiodis Brasilienisis

S: Sporothrix Schenkii

Two haploid cells fuse to become diploid, followed by meiosis.

Explains how they produce daughter cells with a haploid nucleus.

Can undergo fission from one cell into two

 (aka. Binary fission)

Can undergo budding; the yeast will sometimes give rise to a bud which gradually grows and separates out form the mother to become a new cell (blastoconidiosis). Hypha separate from the mother to become a new hypha.

Difference between a fungal and bacterial spore

(Testable Point)

Fungal Spore --> Develops a germ tube (think candida always) --> GT elongates to produce a hypha --> Hypha grow and intertwine to become mycellium

Bacterial spore is a protective form that gives it the ability to withstand adverse environmental conditions (ex:  bacillus and clostridium, gram positive rods)

Vegetative hyphae: The part that goes deep down to acquire nutrients

Aerial hyphae: The part in the air

Note: Hyphae can either be septate or non-septate (fragmented or not)

Stalks with conidia at the end; these are elements of asexual reproduction.

Some are large (macroconidia), some are small (microconidia).

Condiophores that are barrel shaped and joined, specifically referring to coccidia adimycosis (in the environment).

It has a respiratory manifestation.

Arthroconidia in the tissue (skin) we know it's a case of dermatophyte infection (fungal organisms that cause superficial skin infection).

Affects skin, hair and nail.

This fungal pathogen can form allergic or invasive aspergilosis (mortailty is 90% or above).

Lab will know by looking at the hyphas morpholgy.

"Dicor-somethingly branching" - Each oen will split into two.

The hyphae are also septate; there are lateral walls present.

Circular things are yeast, with hypha like structures.

Pseudohypha of candida: Will show constriction at each septa, as if they are separating from each other.

*This is the important way we will distinguish candida, which are described as having a germ tube (very characteristic description).

Spores generated through sexual reproduction

(Not as important, but KNOW THE NAMES)

Zygospores: Thick walled sexual spores

Ascospores: Spores born internally in a sac like structure known as an ascus

Basidiospores: Born externally on a club shaped structure.

Asexual.

A point on the yeast is becoming softened and the cytoplasm is bulging out.

The nucleus is undergoing mi tosis and is going to split in two.

One of the two is going to the bulged cytoplasm.

The cell wall keeps going and it buds off the mother cell.

Daughter cell has the same genomic characteristic as the mother.

Known as budding: Bastoconidiosis

Respiratory pathogen.

Identified based on the budding yeast.

Will be seen in immunocompromised inviduals as meningioencephalitis

(traditionally seen in HIV/AIDs patients)

Paracoccidioidis Brasiliensis Yeast

(Not as high yield on the boards)

Multiple budding.

Steering wheel appearance.

White, creamy, large colonies indicate candida.

We use morphology rather than culture, because a lot of yeast have a similar growth rate.

Stuff he talked about:

Sexually reproduce via zygospores.

Genus mucor, rhizopus, absidia - dangerous pathogens.

Diabetic ketoacidotic and leukemic pateints inherit them and develop encepalopathy.

When describing the pathogen, we say they have "no repsect for anatomic barriers" because they break through bones and invade the frontal lobe of the brain.

Near 100% mortality.

Stuff on slide:

Asexual reproduction through sporangiospores.

Stuff he said:

N/A

Stuf on slide:

Sexual reproduction through ascospores within sacs or asci.

Asexual reproduction through blastoconidia or conida on condiophores.

Genus: Microsporum, aspergilius, trichophyton, histoplasma, blastomyces

Stuff he said;

Reproduction through basidia.

Stuff on slide:

Asexual reproductiongthrough conidiogenesis.

Genus: Cryptococcus.

What he said:

No sexual reproduction.

Ex: Candida - When an individual becomes immunocompromised, it will cause an infection (oral thrus, diaper rash, esophagitis, gastritis, etc.). Can cause a huge number of clinical representation.

What's on the slide:

Asexual reproduction through conidiogenesis.

Genus candida, malasezia, trichosporon, coccidoidis, paracoccidiodis, penicillum, epidermophyton.

Classification of Fungal Infections: Superficial

(WILL BE TESTED ON THIS)

Dermophytes: Skin, hair and nails

*Epidermophyton: Skin and nails

*Microsportum: Skin and hair

*Tricophyton: Involves skin, hair and nails.

Infection is described as tineasis; caused by dermatophytes.

They like keratinized tissue.

Ex of one that likes non keratinized tisue is candida

Classification of Fungal Infections: Subcutaneous

(WILL BE TESTED ON THIS)

Sporothricoses: Rose garden disease

*Patients will work in a garden and come down with subcutaneous ulcers on their skin, most likely in the upper extremity. It won't go away, but will come and go.

*They travel through lymphatics to other regions (satellite lesions).

*Can be caused by candida (ex: diaper rash)

Classification of Fungal Infections: Systemic

(WILL BE TESTED ON THIS)

Deeper structures.

Ex: Aspergillus, pneumocystis.

Classification of Fungal Infections: Opportunistic

(WILL BE TESTED ON THIS)

Fungal infections only invovle the immunocompromised inviduals.

Ex: pneumocystis causing pneumonia in AIDs patients

Tinea Pedis - Cutaneous infection of the foot caused by Trichophyton

Fungal infection of the nail - Caused by Dermatophytes (Tricophyton or epidermophyton)

Candidiasis Albicans - Diaper rash; infection of skin and subcutaneous tissue.

Sporothrix schenkii - Subcutaneous ulcer with an indurated (deep) base, meaning that subcutaenous tissue is involved.

Invasive aspergilosis.

90% mortality; not fun.

Amphotericin B is given, but does not work.

Systemic Mycosis

***Very high yield pathogen***

Interstitial pneumonia

(WE WILL BE TESTED ON THIS)

Looks like ground glass, hazy on a chest x-ray

There are white streaks from the hilum to the periphery.

Description of interstial pneumonia

Pathogen: Pneumocystis

Factors predisposing fungal infections

(IMPORTANT SLIDE, NEED TO KNOW IT)

Steroid hormone therapy

Prolonged antibiotic treatment

Long term treatment with H2 receptor blocking agents (decreases acidity leading to the survival of pathogens)

Diabetes melitus

High starch or sugar containing diets

Compromised immune system due to HIV/AIDs

Lymphocytes.

T- Cells - Offer cell mediated immune response

*Thymus

B-Cells - Offer humoral response

*Plasma cells secrete antibodies

*Have surface receptors that respond to antigens

Phagocytes (Macrophages and neutrophils)

*Differentiated tissue monocytes (microglia in brain, Kupfer cells in liver, macrophages or histiocytes in tissue)

*Eat fungal pathogens, but fungi keep replicating (they survive because of their cell wall)

*Fungus specific helper T-cells (CD4) produced IL-2 and IFN-gamma which activate macrophages and help them elminate pathogenic fungi.

Scrape the tissue.

Use 10% KOH to get rid of everything but the fungus.

Expect to see hpypha under a microscope.

We can use H&E, but some prefer silver staining, can also use cotton blue staining.

*Very conclusive on pneumocystis infection

Typical culture media is saburaud dextrose agar media or blood agar with antibiotics

Sometimes we do it to detect not the antibody, but the antigen of the cryptococcus neoformins something found in HIV patients by checkins CSF: latex agglutination test

*The latex particle is going to have the antibody coated on, patient CSF has polysaccharide antigen, put them together and look for clumping

*Antigen and antibody will cross link, become heavy and settle as a visible clumping (agglutination)

Target ergosterol found in the cell membrane.

*We can target it to either break down or inhibit its synthesis.

*There's only one that doesn't have ergosterol: pneumocystis carinii/iroveci

*Ergosterol is targeted by polyenes, azoles, allyamines

*Flucocytosine inhibits nucleic acid synthesis

*Grisofulvin inhibits microtubule format thereby inhibiting cell division.

Nystatin, Amphotericin B

*Membrane disruption

Terbinatine; Squalene accumulation

*Squalene is a toxic metabolite. When it acuulates it inhibits ergosterol synthesis.

Flucotyosine

*Skip, not used... Just FYI