dimorphics

Question 1

what kind of hyphae do dimorphic have

Answer 1

septate

Question 2

why is it called dimorphic?

Answer 2

two forms; yeast and mold

Question 3

what temp do dimorphics grow best at

Answer 3

30 degrees

Question 4

infective and dignostic form of dimorphic

Answer 4

infective= mold
diagnostic= yeast seen in tissue

can be invasive

Question 5

in order to truely ID something as dimorphic need to

Answer 5

get the colony to convert to both forms

-due to pathogenicity don’t often do this in the lab

Question 6

how are dimorphics diagnosed?

Answer 6

serological by their exoantigens

-several techniques to determine presence of antigen and/or antibody

Question 7

known as north american blastomycosis or Gilchrist disease

Answer 7

blastomyces dermatitidis

-found in Mississippi river valley region

Question 8

natural habitat of Blastomyces dermatitidis

Answer 8

warm moist soil so breathe in spores

most affected organ= lungs; but also bones and soft tissues

rare transmission person to person

Question 9

what can Blastomyces dermatitidis be misdiagnosed as

Answer 9

MRSA because lesions on immunocompromised hosts are filled with pus

Question 10

yeast form of Blastomyces dermatitidis

Answer 10

appear prickly before typical yeastlike colonies are seen

microscopically have “broad base” neck; thick walled cells

Question 11

what media does Blastomyces dermatitidis need to grow a good yeast form

Answer 11

cottonseed agar

Question 12

mold form Blastomyces dermatitidis

Answer 12

slow growing starts white to gray mold

has fuzzy look

septate hyphae
-long conidiospores with single conidia at the top of conidiospores (balloon on a string)

Question 13

common cause of systemic fungal disease

Answer 13

Histoplasma capsulatum

Question 14

what disease does Histoplasma capsulatum cause

Answer 14

Spelunker disease

Question 15

what is spelunkers disease

Answer 15

spores normally inhaled and than travel through the body (bird or bat droppings)

Question 16

what disease rarely causes a cavitary form of lung disease and may resemble TB on an x-ray

Answer 16

Histoplasma capsulatum

1% of cases become systemic and involves RES

Question 17

where is the best place to view Histoplasma capsulatum

Answer 17

buffy coat

• will see yeast staining with Giemsa or wright stain

Question 18

why is history important for Histoplasma capsulatum

Answer 18

if they visited a cave

-infects many organs including gross skin rashes

Question 19

yeast form of Histoplasma capsulatum

Answer 19

difficult to grow - unless you use media with blood
-yeast can be found in WBCs as crescent shaped

LOOK in buffy coat

Question 20

Mold form of Histoplasma capsulatum

Answer 20

-macroconidia called tuberculate erechinulate
-no microconidia
conidia are chlamydospores

SPIKEY looks like COVID-19

Question 21

what disease is called south america blasto

Answer 21

Paracoccidioides brasiliensis

endemic in south america
-most common systemic fungal infection

Question 22

main way to contract Paracoccidioides brasiliensis

Answer 22

eating contaminated raw leaves/ bark infected with fungus

Question 23

physical sign you have Paracoccidioides brasiliensis

Answer 23

granulomas along cheek, tongue, jaw, and gum areas

-may cause painful ulcers in oral region

-think gum

victim will swallow spores so result in intestinal disease

Question 24

yeast form of Paracoccidioides brasiliensis

Answer 24

multiple budding known as “mariners wheel” or “captain’s ship”

-this form easier ID

Question 25

mold form of Paracoccidioides brasiliensis

Answer 25

sterile hyphae with occasional chlamydospores

Question 26

where is Coccidiodes immitis/ posadasii endemic

Answer 26

southwest parts of US in semi-arid, dry areas spores found in soil and become aerosolized (think dry dust ) in some parts people will test 80% skin + for coccidiodes

Question 27

what disease is called river valley fever, san joaquin valley fever, or san joaquin river valley fever

Answer 27

Coccidiodes immitis/ posadasii

Question 28

what does mold produce in Coccidiodes immitis/ posadasii

Answer 28

arthrospores; easily disseminated the older they get so easily airborne -for this reason must work up coccidiodes with class 3 hood, gown and gloves -some lab workers get when working with this

Question 29

how are humans in fected with Coccidiodes immitis/ posadasii

Answer 29

inhale disseminated spores infections result in mild respiratory type illness; self limiting also allergic reaction to spores which purpose "red desert bumps" in some cases pneumonia

Question 30

in vivo, human lungs do not typically produce yeast cells; instead will see

Answer 30

spherules filled with endospores that will spill out when spherules are broken endospores will go and infect other tissue seen in Coccidiodes immitis/ posadasii

Question 31

mold form Coccidiodes immitis/ posadasii

Answer 31

white cottony mycelium; grow arthrospores when staining LPCB will see appearance of arthrospores along with "ghost cell" between arthrospores

Question 32

known as florist's or gardner's disease

Answer 32

Sporothrix schenkii -found in soil and dead vegetation

Question 33

how is Sporothrix schenkii transmitted

Answer 33

rose thorns, wood chips, moss NOT inhaled; transmitted via splinters

Question 34

what will you see at site of infection of Sporothrix schenkii

Answer 34

purplish, non-healing ulcer that develops about 1-2 weeks after initial contact organism will travel along lymph nodes forming ulcers confined to skin

Question 35

yeast form of Sporothrix schenkii

Answer 35

starts looking like any other yeast, but as gets older will turn black and dematiaceous organism yeast cells look cigar shaped

Question 36

mold form of Sporothrix schenckii

Answer 36

thin, delicate septate hyphae long conidiospores with rosette or bouquet type conidia coming of conidiospores fairly easy to convert from yeast to mold

Question 37

most common in INDIA

Answer 37

Talaromyces (penicillium) marneffei

Question 38

Talaromyces (penicillium) marneffei infection

Answer 38

very disseminating in immunocompromised patients -isolated from blood, bone marrow not considered a contaminant like other penicillium

Question 39

unique features Talaromyces (penicillium) marneffei

Answer 39

dimorphic does not grow on cycloheximide prominent red color in mold stage- best with PDA

Question 40

mold stage Talaromyces (penicillium) marneffei

Answer 40

skeleton hands -red color