Mycology random facts Flashcards
cryptococcus usu seen in what type of patients?
majority have problem with cell mediated immunity (but can affect anyone)
cryptococcus
pigeon and kowala poo, soil
- -inhalation –> hematog spread –> dissemination
- 5-10um
- havily encapsulated
cyptococcal meningitis
-prompt tx (100% fatal without)
-hematog spread from apparent lung infx
-NON-inflammatory –> do not get influx of PMNs
-Obstruction of CSF flow and INCREASE ICP due to cells clogging up plumbing
Tx: amphotericin B +flucytosine, f/u with flucon
rapid diagnostic test for cryptococcus
CRAG (cryptococcal antigen test)–> looks for surface antigen
- high sens/spec
- quick and rapid test, cheap
- urine, serum, CSF
candida
- part of normal flora
- dimorphic (buds at 20, germ tubes at 37)
- problem in ICUs/hospitals
- major cause of bacteremia via catheters, trachs
- can travel to multiple organs
diagnostic tests for candida (tl:dr- its a bad test)
1,3-beta-D-glucan
- NOT specific for candida
- binds cell wall component of candida and a lot of other things
- NOT cyrto, mucorales, blastomyces derm
- has a lot of false positives
aspergillus
- mold
- acute angle (45 deg), septate, hyphae
- common in the air, can get into AW easily
- casue dz in vulnerable pops
- propensity to grow in cavitary lesions (old TB)
- “halo sign” on imaging
- causes dz in pt with neutropenia, CGD
hyphae
-grows TOWARDS food source
aspergillus fumigatus
-responsible for majority of dz narrow hyphae -45 degree branching -septate - conidiophores
diagnostic test for aspergillus
- look for galactomanna (crosslinks wall)
- has cross reactivity, no specific
- b-d-galactan –> same test used for candida (not good)
C. neoformans morphology (uworld)
yeast form
round/oval
HEAVILY encapsulated cells with narrow base buds
c neo virulence (uworld)
thick polysac capsule
c neoformans epi (uworld)
- soil and pigeon poop
- opp infx
- resp transmission
c neoformans infx
primary= lung
most common= meningoencephalitis
*can show hematogenous dissemination
c neoformans dx (uworld)
india ink of CSF (halo cells)
latex agglutination for polysach capsule (CSF)
culture on Sabouraud’s agar
methenamine silver (GMS) stain or mucicarmine (red)
c neo tx (uworld)
amphotericin B and flucytosine (acute meningitis)
*fluconozole for lifelong prophylaxis
CNS infection in HIV+ patient is likely…..
cryptococcus neo. most common cause of fungal meningitis
mucorales
mold
- NONseptate hyphae, 90 degree angles
- MUCORMYCOSIS –> pt with DKA, DM (likes high glucose)
- pt with hemachromatosis, or treated with deferoxamine –> likes iron
- FAST growth
rhinoorbitalcerebral mucor
gains entry through cribiform plate, gets into frontal lobes
3 major dz of aspergillus
1) allergic bronchopulmonary aspergillosis (ABPA) –> type I hypersensitivty, assoc with asthma (increased IgE, eos) and CF
2) Angioinvasive aspergillosis –> immunocomp patients/ CGD, disseminates to heart, kidney and brain (ring enhanced lesions). Tx= AmphoB
3) aflatoxins –> HCC
Dematiaceous moulds
black molds
- soil saprophytes
- DIRECT innoculation
- melanin (makes it black) –> bad.
- can disseminate –> can cause meningitis
dimorphic fungi (geographic fungi)
- use phenotypic switching to grow in human body –> THERMAL DIMORPHISM
- cold= mold
- yeast= heat (body)
- histoplasmosis
- blastomycosis
- coccidio (spherule, not yeast)
- paracoccidio
blastomycosis
- eastern US, ohio river valley, great lakes
- central america
- inhaled
- Blasto Buds Broadly (cannon balls)
- same size as RBC
- 8-15um
- disseminates in IC –> to skin and bone (general lee)
is blastomyces in CO?
dogs can get it from praire dogs
What are the two most common forms of dz of blastomyces?
PULMONARY –> (hematogenous dissemination) –> CUTANEOUS BLASTO
-cutaneous can be confused for skin cancer
what type of immune response do you see in blastomyces? what type of immune response do you generally see for fungi?
pyogranulomatous response
fungi= cell mediated
coccidiomycoses
-grows in SPHERULES filled with endospores
-alternatin arthroconidia
-BIG 50-100 um
-southwestern US, Cali, DESERTS
-
dz manifestations of coccidiomycoses
- PNA (turns cavitary) , meningitis
- hemog dissem to skin and bone
- san jaquin valley fever
- “desert bumps” –> erythema nodosum
- desert rhuematism –> arthralgias
***fever, cough, arthralgia
Serology of coccidioides
If you have ab to coccidio, you HAVE INFX
early: immunodiffusion
>1 mo –> Complement fixation (CF)
-CF titer predicts extrapulm dz
-CF titer tells if tx is working
histo
mississippi and ohio river valleys
- ANYTHING to do with birds
- resp tract transmition
- Histo Hides in macrophages
- MUCH smaller than RBC
- rapid serum, urine antigen
dz from histo
PNA
- calcifications
- late chronic looks like TB
- may see elevated inflamm markers (LDH, ferritin, non specific)
- targets RES –> HSM
do you get blood cultures for histo? what kind?
Takes weeks to grow. do LYSIS CENTRIFUGATION. Spin it down, then try to culture it
how long do you treat these disseminated diseases?
like years.
sporothrix schenckii
- dimorphic assoc with ZOONOTIC transmission –> dogs and cats
- cigar shaped
- budding yeast
- grows in branching hyphae with rosettes of conidia
- lives on vegetation –> “ROSE GARDER dz”
- ascending lymphangitis
how do you usually get sporothricosis? how do you treat sporothricosis?
DIRECT innoculation (roses).
itraconazole or potassium iodide
sporothrix (slide from class)
aggriculture
children, men
world wide + hyperendemic (peru)
zoonotic
preogression of sporo
skin ulcer –> ascending lymphangitis –> these areas up the lymph chain become necrotic
does sporo disseminate? is it common? what are risk factors?
yes, uncommon
where: joint, bone, lung, meninges
who: EtoH, DM, late HIV, COPD
paracoccidiodies
- rare
- latin america
- sub tropical, mountainous climates where coffee can grow
- agg workers on coffee plantations
- LONG incubation (decades)
- adults
- males
- can present like COPD
why would culture of open skin wounds be discouraged?
they generally just grow normal skin flora
