Systemic Fungal Infections Flashcards
what are the steps in ID
- what is the dx
- microbiological testing orders
- empiric antimicrobials
- culture directed therapy
what are unicellular, colorless, oval shaped fungi that reproduce by budding
yeast
what are multicellular, colorful, branching with hyphae/ septa
molds
what fungi are yeast in the heat and mold in the cold
dimorphic fungi
name 2 yeasts
candida spp
cryptococcus spp
name 3 molds
asperigillus
mucorales/ rhizopus
dermatophytes
name 2 dimorphic yeasts
histoplasma spp
blastomyces
_____ pathogens cause disease in otherwise healthy individuals if exposed to infectious microorganism
primary
_____ cause disease in pts who can’t defend themselves against fungus
opportunists
dimorphic fungi is a
1. primary pathogen
2. opportunist
3. both, depending
1
yeast is a
1. primary pathogen
2. opportunist
3. both, depending
2
aspergillus is a
1. primary pathogen
2. opportunist
3. both, depending
3
aspergillosis in a severely immunodeficient pt causes
invasive pulmonary aspergillosis
aspergillosis in a moderately immunodef pt causes
chronic cavitating pulmonary aspergillosis
aspergillosis in a strong and immunocompetent pt causes
allergic bronchopulmonary aspergillosis (ABPA)
list 2 early gen azole antifungals
fluconazole
itraconazole
list 3 late gen azole antifungals
voriconazole
posaconazole
isavuconazole
name 1 echinocandin
micafungin
caspofungin
anidulafungin
name 2 polyene antifungals
amphotericin B
nystatin
name 2 misc antifungals
flucytosine
terbinafine
polyene antifungal MOA
directly inserts pores into ergosterol cell wall
polyene antifungals are used for
endemic mycoses, resistant fungi
echinocandins MOA
inhibits b-1,3-glucan synthase
echinocandins are used for
invasive candidiasis
azole antifungal MOA
inhibits lanosterol 14-a demethylase (CYP enzyme)
azole antifungals are used for
candida, invasive mold infections
T or F: there is bacterial in the CNS and brain
F- should always be sterile
which of the following are sterile sites
1. biliary tree
2. skin
3. peritoneum
4. LRT
3
opportunistic candidiasis yeast infection of the mouth/ esophagus is common in pts with ______ from chemo but any pt who is even _____________ (ex- newborns)
mucositis
partially immunodeficient
vaginal candidiasis is an _____ yeast infection in those who are locally ______
opportunistic yeast infection
locally immunocompromised
candidemia means
candida spp isolated in blood
what is invasive candidiasis
generic term for systemic fungal infection with candida spp (can involve distant organs0
yeast in blood represents
a major breakdown in normal host immune capability
T or F: normally our immune system is extremely effective at clearing yeast in blood
T- yeast in blood is never a contaminant + req urgent assessment + tx
- 30% will die
loss of host immune defense may be due to (3)
exposure to broad spec antibiotics
uncontrolled DM
neutropenia
loss of host barrier defenses may be due to (3)
IV catheters
TPN
intraabdominal surgery
candidemia can cause _____ or ______
nonspec febrile illness
septic shock
candida can cause ____ by seeding from initial source
metastatic infection
sites of possible candida seeding include
candida endophthalmitis (eyes)
infective endocarditis
osteoarticular infections
hepatic/ splenic abscess formation
candidemia should prompt eval for
potential seeding sites for metastatic infection
metastatic sites of infection can serve as _____ or _____ of ——–
new sources or niduses of persistent infection
how long does it take to get the first gram stain report
12-24hrs
how long does it take to get an identity report
24-48hrs after yeast is isolated
how long does it take to get a susceptibility report
24-48hrs, sometimes 3-4 days after receipt of pathogen identity = need to start empiric antifungals beforehand
____________ are not detectable via regular bacterial blood cultures
molds- require special fungal blood cultures
can yeast be found in regular bacterial blood culture? how long will it take/
yes- will flag as yeast on gram stain
as late as 4-5 days
T or F: yeast in nonsterile sites is not always pathogenic
T
what is the majority of the candida species
candida albicans
T or F; antifungal drug resistance is a prominent clinical issue
T- but not the same way as bacteria
why is antifungal drug resistance not the same as antibacterial resistance
fungi do not make antifungal hydrolyzing enzymes (generally)
takes years of exposure and circulation to develop resistance
rarely pass resistance mechs to each other
how is antifungal resistance developed
antifungal pressure can select for specific drug resistant species
often involves drug efflux pumps or target enzyme mod mechs
antifungals should be assessed on day _______ and again on day ____ for appropriateness
day of prescription
again on day 3
why do pts will have increased mortality rate despite adequate antifungal tx
antifungal tx is only one component of tx
most importantly - effective source control of index source + hematogenous metastatic sites
ongoing immunodef may make CL difficult
(5 causes of apparent clinical failure)
what are 5 causes of apparent clinical failure
lack of source control
immunodef
wrong dx
other diseases/ infxns
delayed improvement
T or F: tx failure infers antifungal drug failure
F- may be due to lack of source control, immunodef, wrong dx, other diseases, delayed improvement
cryotpococcus is an _________ associated endemically with ___________. it is a ___ (opportunist/ primary pathogen)
encapsulated yeast
vancouver island
opportunist
how is cryptococcosis acquired
inhalation of airborne yeast
typically only in immunocomp pts
what is the clinical presentation of cryotococcosis
pulmonary diseases (uncommon)- usually sequestered into granulomas in lung and dies
subacute meningitis
umbilicated skin lesions
how is cryotococcosis dx
CrAG
cryotococcosis tx includes
amp B + flucytosine (induction)
fluconazole (maintenance)
histoplasmosis acquisition
inhalation of airborne microconidia- bat droppings
clinical presentation of hsitoplasmosis
asymp in 90% pts
passess as CAP in most cases
some may develop pulmonary nodules/ cavitation (TB/ cancer), mediastinal fibrosis + disseminate if immunocomp to CNS, bone marrow, spleen (higher risk if on TNF-a inhibitors)
how is histoplasmosis dx
serology testing, urinary histoplasma Ag, culture
histoplasmosis tx
initially amp B then step down to itraconazole
blastomycosis is a _______ with characteristic ___________ yeast phenotype
dimorphic fungi
broad based budding
acquisition of blastomycosis is from
INH airborne conidia
traumatic inoculation rare
what is the clinical presentation of blastomycosis
asymp in 50% pts, sometimes constitutional illness
pulmonary blastomycosis, but often combo wtih cutaneous
recurrent, extrapulmonary, cutaneous, joint, GU/prostate, CNS disease (chronic meningitis)
how is blastmycosis dx
serology testing first, EIA from urine/serum, culture
how is blastomycosis tx
ampho B, then step down to itraconazole
mucormycosis group molds are rapidly growing _______ molds that are relatively _____
hyphal molds
relatively aseptate
mucormycosis comes from
bread molds
mucormycosis acquisiton
INH
mucormycosis is classically assocaited with
DKA and uncontrolled diabetes
(also causes prolonged neutropenia >14 days), heme malignancy, iron overload sx- hemochromatosis)
what is the clinical presentation of mucormycosis
Rhinocerebral mucormycosis – destructive soft-palate eschar/nasal/sinuses disease which can extend into the CNS/skull
Pulmonary mucormycosis – rapidly progressive lung-necrotizing disease in neutropenic patients, tough to parse from aspergillosis; can disseminate; is angioinvasive and has HIGH mortality rate
Cutaneous mucormycosis – involving necrotic skin lesions
tx for mucormycosis
SURGERY/DEBRIDEMENT MOST IMPORTANT. Initially Amphotericin B but possibly isavuconazole as first-line with salvage options, prolonged treatment
what are 3 antifungal stewardship jobs for pharmacists
de-escalation with final culture reports
IV-PO step down (most are highly bioavailable)
duration of tx (limit)
