Develop along vegetative hyphae Thick-walled, numerous, elongated • May be consecutive or alternative

Small buds seen in yeast that divide asymmetrically Not present in division by fission

Fungal pathogens/Parasites Flashcards by Mia McNulty

Characteristics of fungi

heterotrophic
3uM-hundreds of feet long
sexual or asexual reproduction
rigid cell walls made of chitin but have membrane bound organelles
-ergosterol in their cell membrane
some species have a polysaccharide capsule

How well did you know this?

Not at all

Perfectly

Saprobes

fungi that live on dead/decaying organic matter

How well did you know this?

Not at all

Perfectly

Symbionts

fungi that lice on another organism and it is mutually advantageous to both

How well did you know this?

Not at all

Perfectly

Commensals

fungi that live on another, no detriment to host

How well did you know this?

Not at all

Perfectly

parasites

fungi that live on another, detriment to host

How well did you know this?

Not at all

Perfectly

Fungi can occur in two basic forms:

1) Yeast

2) Mold (hyphae)

How well did you know this?

Not at all

Perfectly

Yeast

unicellular type of fungi. They reproduce via budding or fission. Colonies look moist/mucoid. Sometimes they can look like hyphae if they are elongated into pseudohyphae

How well did you know this?

Not at all

Perfectly

Mold

Type of fungi. made of filamentous growths (hyphae). can form a mycelium. Hyphae can be septal or nonseptal

How well did you know this?

Not at all

Perfectly

A mass of hyphae is called a____

mycelium

How well did you know this?

Not at all

Perfectly

Are all organisms exclusively yeast or hyphae?

No, some fungi are dimorphic and can exist in a yeast or a hyphal form depending on the environment

How well did you know this?

Not at all

Perfectly

Which fungi are dimorphic?

Sporothrix
coccidoides
histoplasma
blastomyces
paracoccidoides

How well did you know this?

Not at all

Perfectly

Rhizoids

specialized hyphae that look like roots from vegetative hyphae

How well did you know this?

Not at all

Perfectly

Condida

asexual spores that come off of aerial hyphae . Can be two types: macrocondida or microcondida

How well did you know this?

Not at all

Perfectly

Macrocondida

large multinucleate spore

How well did you know this?

Not at all

Perfectly

Microcondida

small unicellular spore “birds on a wire appearance”

How well did you know this?

Not at all

Perfectly

Sporangia

endospores enclosed in membranous sac. Held up by a sporangiophore

How well did you know this?

Not at all

Perfectly

Sporangiophore

specialized hyphae bearing sporangia

How well did you know this?

Not at all

Perfectly

Chlamydospore

Form along vegetative hyphae
• Round and very thick-walled
• Resistant to adverse environmental conditions • May be terminal or intercalary chlamydospores

How well did you know this?

Not at all

Perfectly

Arthrospores

Develop along vegetative hyphae

* Thick-walled, numerous, elongated • May be consecutive or alternative

How well did you know this?

Not at all

Perfectly

Spherules

Develop during yeast phase in some
organisms (Coccidioides immitis)
• Spherules filled with small endospores

How well did you know this?

Not at all

Perfectly

Blastoconidia

Small buds seen in yeast that divide asymmetrically

* Not present in division by fission

How well did you know this?

Not at all

Perfectly

Thallus

a cultured fungal colony

How well did you know this?

Not at all

Perfectly

Floccose

wooly

How well did you know this?

Not at all

Perfectly

Lanose

cottony

How well did you know this?

Not at all

Perfectly

Glabrous

smooth

Dematiaceous

pigmented

Geophilic

acquired from soil

Zoophilic

acquired from animals

Anthropophilic

acquired from humans

Sabouraud’s agar

non-selective auger used as screening media

Mycocel/Mycobiotic

Sabouraud’s agar plus antibiotics

Dermatophyte test medium (DTM)

Sabouraud’s agar plus antibiotics & pH indicator

PAS/D–stains the

chitinous cell wall of fungi

Mucicarmine

stains mucopolysaccharide capsule

Gomori’s methenamine silver

stains cell wall

Amphotericin

an example of a POLYENE Bind to and inhibit ergosterol assembly “amphoterrible” – “shake and bake” “Polyenes punch holes in cell membrane”

Imidazoles/Triazoles

• Interfere with ergosterol synthesis • Inhibit 14-demethylase • Inhibit human sterol synthesis to lesser extent • Metabolized via the cytochrome pathway • Some risk of fulminant hepatic toxicity Ex: ketoconazole

Allylamines/Benzylamines

• Block ergosterol synthesis at an earlier point • Inhibit squalene epoxidase • Accumulation of squalene is fungicidal • Still metabolized by cytochrome pathway • Lesser but existent risk of liver toxicity ex: terbinafine

Echinocandins

* Newest class of antifungals- 2002 * Act via inhibition of 1,3-glucan synthase * Priniciple activity against Candida and Aspergillus

Griseofulvin

– Inhibits microtubule/spindle complex | -eat with fatty meal

Flucytosine

antimetabolite that inhibits DNA synthesis | fungistatic.

Ciclopiroxolamine

chelates important metals needed for fungal development

What can you add to KOH or DMSO stains the chitinous fungal cell walls a grey-green color and this makes the direct microscopic examination easier?

chlorazol E black stain

definitive host

where parasites undergo sexual reproduction

intermediate host

where parasites undergo asexual reproduction

Taxonomic groups of helminths

1. Roundworms/nematodes 2. Flatworms/trematodes/flukes 3. Tapeworms/cestodes

Taxonomic groups of protozoa

1. Amebas 2. Flagellates 3. Cilliates 4. Sporazoa Microsporidia

Schistosomes are what type of worm?

trematode/flatworm

Schistosome eggs are excreted in the feces, hatch, and release _______

miracidia

miricidia go on to infect ______, the intermediate host of a schistomiasis infection

snails

After the snail has been infected, the parasite generates ______ inside the snail

sporocytes

_______ are released by the snail into the water and are free-swimming parasites

cercariae

What part of the life cycle of a schistosome infection penetrates the human skin?

cercariae penetrate the human skin and lose their tails to become schistosomules

cercariae penetrate the human skin and lose their tails to become _________

schistosomules

Schistosomules gain access to the circulation and migrate to what area to mature into adult worms?

the schitosomules migrate into the portal blood to mature

After maturation, the mature worms migrate to the _____ veins or the _____ _____ of the ____ to mate

mesentaric | venous plexus of the bladder

The acute phase of schistomiasis infection is characterized by ____ 2-3 days after infection

dermatitis

Following dermatitis, acute phase of schistomiasis infection is characterized by:

serum sickness like illness "katayama fever 4-8 weeks post infection and lymphadenopathy and hepatosplenomegaly

Chronic schistomiasis infection

granulomatous/fibrotic changes to liver or bladder in response to deposited eggs. Eosinophils--> scarring. SSx= diarrhea, abdominal pain, ascites/hematuria, bladder cancer

What pathogens cause malaria

the plasmodium family: vivax, oval, malaria and falciparum

Cycle of malaria

Mosquitos bite people, sporozoites infect hepatocytes replicate, Merozoites are released into blood, infect RBCs, replicate, RBCs sucked up by mosquito, Sexual development (gametes fuse in the mosquito intestine)

Untreated malaria leads to what kind of fevers?

periodic, synchronized fevers

Anemia from RBC lysis leads to

splenic sequestration, decreased bone marrow function, hemoglobinuria (backwater fever)

SSX of malaria

jaundice, hypotension, tachycardia, fever, hepatosplenomegaly, glomerulonephritis, cerebral malaria, inadequate blood flow to organs, multi organ failure

Fungal pathogens/Parasites Flashcards

(64 cards)