Dimorphic fungi turn into yeast at _____ temperature, and mold at ____ temperature
High; low
When breathed into our lungs, dimorphic fungi become ____ form.
Yeast
Is histoplasma a dimorphic fungi?
Yes
True/False: histoplasma is not a dimorphic fungi
False; histoplasma IS a dimorphic fungi
Where is Histoplasma is often found in?
Bat and bird poop ; Mississippi river valley
True/false: Histoplasma only has a microconidia form
False; It has both macroconidia and microconidia forms
Which form of histoplasma is most infectious
Microconidia
Tuberculate macroconidia refers to which fungi?
Histoplasma capsulatum
Which form of histoplasma exhibit finger like projections from their surface?
macroconidia
True/False: Microconidia form of histoplasma has finger like projections from their surface
False; microconidia has a smooth surface, it is macroconidia that has the finger like projections
True/False: Histoplasma capsulatum is an encapsulated yeast
False
Infectious histoplasma grow in which host cells?
Unactivated macrophages
Once histoplasma conidia is breathed in, where does it transform into yeast in the human body?
In macrophages
Could Histoplasmosis result in granulomas?
Yes
True/false: histoplasmosis remains asymptomatic in most healthy individuals following low level exposure
True
True/False: histoplasmosis is usually self limited
True
Can histoplasmosis develop cavity formation?
Yes, in patients with emphysema
Where are sites in the body that histoplasmosis often disseminates?
Liver and spleen
True/False: chronic cavitary pulmonary histoplasmosis often seen in patient with pulmonary fibrosis
False; seen in COPD/ emphysema patients
How is Histomplasma diagnosed?
antigen detection for H. capsulatum galactomannan
What does histoplasmosis causing mild pulmonary dz look like on xray?
Focal infiltrates and hilar or mediastinal lymphadenopathy
What does severe pneumonia caused by histomplasma and blastomyces look like on xray?
Bilateral diffuse nodular infiltrates
What is the enzyme that antigen detection test is looking for in H capsulatum diagnosis?
Galactomannan
Galactomannan is an enzyme associated with which fugnal antigen detection test?
Histoplasma capsulatum
Aspergillus
True/false: Histoplasma is a primary pathogen/ major endemic mycoses
True
What does primary pathogen mean?
Can cause disease in healthy people
True/false: primary pathogens only cause disease in immunocompromised people
False; they can cause disease in everyone, even healthy people
What is the characteristic morphology of Blastomyces dermatitidis?
Big broad base budding yeast and lollipop conidia
See big broad base budding yeast and lollipop conidia, think which organism?
Blastomyces dermatitidis
Is Blastomyces a dimorphic fungus?
Yes
What form does Blastomyces take once is inhaled?
Yeast
What form does Blastomyces take when it is in the environment?
Mold
What kind of hyphae does Blastomyces have?
septate hyaline hyphae
What type of conidiophore does Blastomyces have?
‘Lollipop”
True/fast: yeast form is the most infectious form of Blastomyces
False; conidia is the most infectious
True/false: Blastomyces disseminate to skin, can get cutaneous lesion without pulmonary lesion
True
Can blastomycosis form granulomas?
Yes
True/false: blastomycosis is proceeded by skin or osteoarticular lesions
True
What do skin lesions caused by Blastomyces look like?
Verrucous – rough, warty
Irregular gray or violet borders
What is the cxr imaging look like for blastomycosis?
Patchy pneumonitis
Can blastomycosis disseminated anywhere?
Yes
Which fungus has pilot wheel budding yeast?
Paracoccidioides
Is paracoccidioides a dimorphic fungus?
Yes
True/false: paracoccidioides is a dimorphic fungus with broad base budding yeast
False; they are dimorphic but they have pilot wheel budding yeast
What do yeast form of paracoccidioides resemble?
Pilot wheel
Mold form of paracoccidioides have what kind of septate?
Hyaline septate hyphae
What is the morphology of paracoccidioides?
Varies
What makes the pilot wheel appearance in yeast form of paracoccidioides?
Yeasts with multiple buds
List 4 dimorphic primary pathogens:
Coccidioides
Histoplasma
Blastomyces
Paracoccidioies
True/False Pneumocystis jirvecii is a dimorphic fungus
False; it is atypical
What is the cell membrane of Pneumocystis jirvecii made up of?
Cholesterol instead of ergosterol
True/false Pneumocystis jirvecii’s cell membrane is made up of ergosterol instead of cholesterol
False; the exact opposite
True/false: pneumocystis jirovecii does not respond to antifungal treatment
True
What forms are seen in pneumocystis jirovecii in vivo?
Cysts and trophic forms
True/false: P jirovecii is a leading cause of morbidity and mortality in HIV patients
True
What is xray imagining look like in pneumocystis pneumonia?
Diffuse, bilateral interstitial infiltrates
Ground glass appearance
Alveoli filled with fluffy material
When xray shows ground glass appearance and alveoli with foamy material, think what organism?
Pneumocystis
Which organism can you see both cystic and trophic forms in vivo?
P jirovecii
How is visualizing trophic and cyst forms of P jirovecii done?
Direct fluorescent antibody staining with fluorescein-conjugated monoclonal antibody
How do yeasts divide?
By budding
What is the cellularity of yeasts?
Unicellular eukaryotes
True/false: yeasts are unicellular prokaryotes
False; they are unicellular eukaryotes
What is blastoconidia
Buds of yeasts
What happens when buds of yeast don’t detach?
Form pseudohyphae
What do yeasts generally look like on petri dish?
Smooth and small, bacterial-like
True/false: yeasts are bacterial-like when cultured on petri dishes
True
What is the cellularity of molds?
Multicellular eukaryotes
True/false: molds are multicellular filamentous eukaryotes
True
What are hyphae?
Branching tubules of molds
What are functions of fungal spores?
Reproduction
Survival/ transmission
When do hyphae form spores?
When it is cool enough, ie in the environment
True/false: yeast for spores when inside the body and that is how fungi becomes infectious
False; spores are form by hyphae outside the body
True/false: fungal pneumonias are often nodular, granulomatous and form cavities
True
What method is most often used to diagnose molds?
Microscopically
Why is KOH used during microscopic examination for fungal infection?
KOH gets rid of the host tissue
True/False: most fungi stain Gr-
False; they stain Gr +
What is the typical media for clinically important fungi?
SDA = sabouraud dextrose agar
ABHI= sabouraud dextrose media + BHI media
True/False: some endemic mycoses are part of the normal microbiota
False; they are not
True/false: opportunist fungi only affect immunocompromised people
True
True/false: some opportunist fungi are part of the normal microbiota
True
True/False: endemic mycoses can infect normal healthy people
True
True/false: cryptococcosis is classically classified as opportunist but a select species is a primary pathogen
True
Generally, endemic mycoses are ____, and it is ___ in soil and ___ or ____ in vivo
Dimorphic
Mold
Yeast
Spherule
Which fungi make spherules in vivo?
Coccidioides
Endemic mycoses ___(can/cannot) transmit from human to human
Cannot
Why can’t endemic mycoses be transmitted from human to human
Because it is the conidia(spore) that are inhaled, in human the fungi is in yeast form
True/false: African Americans and Filipinos are risk factors for dissemination of endemic mycoses
True
What is another name for coccidioidomycosis?
Valley fever
Coccidioides when inside humans takes _____ form, which contain ____.
Spherules
Endospore
Are spores from coccidioides sexual or asexual spores?
Asexual
What is arthroconidia?
Asexual spores (ie in coccidioides)
Coccidioides Spherules inside our lungs divide to form intracellular ____, and these come out of the spherules and disseminate to other parts of the body and becoming spherules there.
Endospores
How do coccidioides arthroconidia appear in microscopic slides?
Hyaline
Barrel-shaped, thick-walled
Ghost junctions
True/false: spherules are huge that is why macrophages cannot engulf them
True
What is the most important factor for dissemination?
Decreased cell-mediated immunity
What is the gold standard for diagnosis of coccidioides?
Culture
Confirm with DNA probe
List 3 opportunistic mycoses:
Candida
Cryptococcus
Aspergillus
Pneumocystis jirovecii
True/false: Cryptococcus is always mold
False; they’re always yeast
What is hallmark appearance of Cryptococcus?
Encapsulated yeast
Narrow base bud
True/false: Cryptococcus have a big broad buds like Blastomyces
False; opposite, Cryptococcus have narrow-based buds
When do Cryptococcus become encapsulated (have capsules)?
In vivo (in human)
You see cryptococus on microscopic slide without capsule, what does that tell you?
That it is from the environment, not in vivo
True/false: Cryptococcus is in non-capsulated buds (yeast form) in the environment
True, they are always yeasts
Cryptococcus is urease ____?
Positive
Which Cryptococcus species causes CNS infections?
C. neoformans
Which Cryptococcus species leads to pulmonary infections?
C. gattii
True/False: C. gattii behave like primary pathogens
True
C gattii come from which organism?
Trees
See trees, think which organism?
Cryptococcus gattii
Which cell do Cryptococcus replicate in?
Unactivated macrophages
what are virulence factors for Cryptococcus?
Facultative intracellular in unactivated macrophages
Large polysaccharide capsule
Phenol oxidase – makes melanin in cell wall
Urease positive
True/false: Cryptococcus have large polysaccharide capsule
True
True/False: Cryptococcus has phenol oxidase that catalyzes conversion of phenolic compounds into ergosterol
False; into MELANIN
True/false: Cryptococcus has melanin in cell walls
True
Why is urease a virulence factor?
Converts urea to ammonia and ammonia is toxic to tissues
Is Cryptococcus transmissible human to human?
No
What is cryptococcoma?
Granulomatous pulmonary lesions
Aspergillus is always a ___.
Mold
True/false: aspergillus, like Cryptococcus, is always a yeast
False; Aspergillus is not like Cryptococcus, it is always a mold, never a yeast
Aspergillus has what kind of hyphae?
Septate hyphae
What is hallmark appearance of aspergillus?
Septate hyphae
V shape, dichotomous branching
Conidia looks like flower
Conidia that look like flowers, tells you is which organism?
Aspergillus
What is the inhaled part of fungi called that is infectious?
Conidia
What is the biggest risk factor for aspergillus?
Neutropenia
When patient is neutropenic, that quickly leads you to think he/she at risk for which fungal infection?
Aspergillus
True/false: aspergillus is an opportunist
True
What is the most common cause for aspergillus infection?
Construction-related nosocomial infection
i.e. surgical patients in contaminated air-handling system
what are virulence factors for aspergillus?
Angioinvasive
Hyphae
True/false: Cryptococcus is angioinvasive
False; it is aspergillus because they have hyphae
What is the definitive diagnosis for aspergillus in pulmonary infection?
