Mycology Flashcards
yeast
candida albicans
cryptococcus neoformans
pneumocystis jirovecii (PCP)
candidal esophagitis
AIDs, leukemia, lymphoma sx: painful swallowing substernal chest pain feeling of obstruction when swallowing
DDx: CMV, herpes esophagitis
oral thrush
neonates
steroids
diabetes AIDS
DDx: oral hairy leukoplakia
candidal vulvovaginitis
diabetic patients, women with recent antibiotic use sx: severe itching edema vaginal discharge acidic pH
candida albicans diaper rash
jagged edges, satellite lesions
candical intertrigo
erythematous central lesions with satellite lesions
candida bloodstream infections
central lines
drug users
cancer patients
transplant patients
leading to endophthalmitis, endocarditis
chronic mucocutaneous candidiiasis
mucous membranes, hair, nails
candida albicans diagnosis
blood culture
germ tubes- small projections on side of cell, usually within 90 minutes
treatment for candida albicans
superficial infections: nystatin, clotrimazole, fluconazole
systemic infections:
fluconazole, amphotericin B, echinocandin
cryptococcal meningitis
AIDS
cryptococcus- wide or narrow? where is it found? what can you use to culture it? what can you use to stain it?
is there a serological test?
what does it look like on imaging?
heavily encapsulated yeast, reproduces by narrow- based budding
soil and pigeon droppings
can be cultured on most bacterial and fungal media
often cultured on Sabouraud’s agar
stain with India ink
serological test for cryptococcal antigen is more sensitive than India ink
latex agglutination test to detect polysaccharide capsular antigen
“soap bubble” lesion on imaging
How to treat cryptococcus
amphotericin B + flucytosine
followed by fluconazole
PCP PNA
what stain?
what does it look like on imaging?
atypical
diffuse interstitial PNA that developed into potentially fatal PNA in immunocompromised patients
Dx: silver stain
imaging- ground glass appearance of interstitial infiltrates
PCP PNA treatment
TMP-SMX (begin with IV, transition to oral)
sulfa allergy: pentamidine, clindamycin + primaquine
ppx when CD4
Molds
Aspergillus fumigatus
mucor
rhizopus
Aspergillus fumigatus
allergic bronchopulmonary aspergillosis
fungus ball (aspergilloma) invasive aspergillosis
where is aspergillus found
ubiquitous
soil, air, water, food
what does it look like?
narrow septate hyphae that branch at acute angles (45 degrees)
aspergillus treatment
voriconazole
lipid formulation of amphotericin B
Mucor and Rhizopus
where are they found? who gets infected? what do they look like?
cause mucormycosis
ubiquitous
invasive disease in severely immunocompromised, trauma patients, diabetics
broad, irregularly shaped, nonseptate hyphae branching at right angles
patients with DM, DKA, leukemia, neutropenia, with mucormycosis
rhinocerebral mucormycosis
facial pain
HA
Mucor grows into vessel walls, leading to large necrotic lesions (look like eschar)
CN deficits, blindness
Dx: biopsy
Tx: surgical debridement, amphotericin B
Dermatophytes
Trichophyton
Microsporum (dog or cat reservoir)
Epidermophyton
Malassezia furfur
What infections are commonly caused by dermatophytes?
how do we diagnose?
tinea pedis (feet) tinea cruris (groin) tinea capitis (head) tinea unguium (nails) aka onychomycosis
on the body it is called ringworm
diagnosis: fungal hyphae or spores on skin or hair samples
culture
how to treat fungal skin infection
topical terbinafine or azole
extensive skin infection or scalp/hair infection
PO terbinafine or azole
tinea unguium (nails) aka onychomycosis
trichophyton rubrum
thickened, discolored nails PO therapy recommended terbinafine itraconazole fluconazole treat for a year (fingernails clear faster than toenails)
Malassezia furfur
hypopigmented patches.
nonpruritic
KOH prep: spaghetti and meatballs
topical azole, selenium sulfide
causes diaper rash
candida albicans
opportunistic mold with septate hyphae that branch at a 45 degree angle
aspergillus
opportunistic mold with irregular nonseptate hyphae that branch at wide angles (>90)
mucor, rhizopus
causes thrush in immunocompromised patients and vulvovaginitis in months
candida albicans
known for causing pneumonia in AIDS patients
PCP
yeast known for causing meningitis in AIDS patients
cryptococcus meningitis
dimorphic fungi
mold form at 20 degrees C
yeast form at 37 degrees C
cold mold, heat yeast
systemic mycoses versus tb
both cause granulomas, however molds form non-caseating granulomas unlike TB
what kind of agar for dimorphic fungi?
Sabourad agar
Histoplasma capsulatum
Mississippi and Ohio river valleys in bird and bat guano
on histology, you will see macrophage filled with histoplasma (smaller than RBC)
histo hides within macrophages
Blastomyces dermatitidis
states bordering Mississippi and Ohio river basins up to Canada
Central America
enters via pulmonary route
causes pulmonary infection
disseminates to the rest of the body
skin, bone, granulomatous nodules
coccidiodes immitis
Southwestern US.
“San Joaquin Valley Fever”
disease incidence may increase after sandstorms or earthquakes
Mycelial (soil) and spherule
forms arthroconidia (barrel shape)
can become airborne and deposit themselves in the human lung
The arthroconidia form spherules within the lung, which divide until the spherule becomes so packed with daughter cells that it bursts
infections are often asymptomatic or mild
severe PNA or disseminated disease
- CNS (meningitis)
- skin findings
- bones
- joints
Paracoccidiodes brasiliensis
latin america is the only known endemic area
enters through respiratory route
disseminated progressive disease
-severe PNA
-granulomatous changes in mucous membranes and skin
Captain’s wheel appearance
Sporothrix Schenckii
dimorphic fungus soil and vegetation often introduced by a thorn sphagnum moss nodules appear along the draining lymphatics (painless)
no systemic sx
Tx: itraconazole
potassium iodide
found in SW US including west Texas and California
coccidioides immitis
found in Mississippi and Ohio River basins
histoplasma capsulatum
causes San Joaquin Valley fever
coccidioides immitis
found in rural Latin America
paracoccidioides brasiliensis
associated with plant thorns and cutaneous injury
Sporothrix schecnkii
found in states east of the Mississippi River
blastomyces dermatitidis
found in bird and bat droppings
histoplasma capsulatum
mold form contains barrel- shaped arthroconidia
coccidioides immitis
associated with dust storms
coccidioides immitis
broad- based budding of yeast
blastomyces dermatitidis
multiple budding of yeast form
paracoccidioides brasiliensis (captain’s wheel)
