Exam #4: Antifungal Agents (Moniri) Flashcards
The Fungal Kingdom includes: (4)
- yeasts
- molds
- rusts
- mushrooms
Most fungi are SAPROPHYTIC. What does this mean?
they live on dead organic matter
Few fungi are obligate animal parasites (CAN ONLY LIVE IN A HOST). What are some examples? (2)
- candida albicans
- trichophyton rubrum (cause ringworm)
What are 4 characteristics of fungi?
- single cell
- reproduce by budding
- can grow in chains
- produce spores which can be transported
What fungi?
- cause infection of the skin, hair, and nails
- historically cause cosmetic fungal infections
dermatophytes (tinea)
What fungi?
dependent on temperature, they have different morphologies
thermally dimorphic fungi
What fungi?
has come about due to the use and overuse of fluconazole
candida parapsilosis and candida glabrata
What fungi?
unique b/c its encapsulated by polysaccharide capsules and CAN cause FUNGAL meningitis
cryptococcus neoformans
Where do dermatophytes (tinea) obtain their nutrients?
from attacking protein keratin (prevalent in skin,hair, and nails)
T/F Dermatophytes (tinea) are named for the site of infection rather than by species
TRUE
tinea capitis
hair, scalp
tinea pedis
feet
tinea mauum
hands
tinea unguium
fingernails
Why is treating tinea ungium difficult?
b/c the nail that we see is dead, but the fungi is living in the precursor cells
(nails only starts to look better once the nail grows out)
What bacteria are also encapsulated with polysaccharide? (3)
- s.pneumoniae
- n. meningitis
- h. influenzae
T/F Candida albicans is the MOST common YEAST cause of disease
TRUE
YEAST
C. parapsilosis AND C. glabrata
nosocomial infections that are due to overuse of -azoles
T/F The normal flora (pharynx, GI, vagina, surrounding skin) ALL contain YEAST
TRUE
specifically albicans
Principal cause of vaginal yeast infections and oral thrush
yeast
In the following patients, YEAST can cause deep-seeded lethal infections:
- AIDS
- Hematopoietic stem cell transplant
- Neutropenics
YEAST
crytococcus neoformans
-in immunocompetent–> _______
-in immunoCOMPROMISED–> ______
competent: self limiting lung infections (cold)
compromised: disseminates to other organs, particularly CNS (i.e. CRYPTOCOCCAL MENINGITIS)
- blastomyces dermatitidus
- paracoccidiodes brasiliensis
- coccidioides immitus
- histoplasma capsulatum
are all examples of?
thermally dimorphic fungi
_________: All live in soil and infections arise as a result of contaminated dust
thermally dimorphic fungi
What is the only way to definitively diagnose a thermally dimorphic fungal infection?
via a sputum culture
What thermal dimorphic fungi?
- inhaled into lungs, circulate and multiply through blood and lymph to any organ
- can present in a variety of ways
- mortality rates in treated cases differ depending on immune system
blastomycosis- blastomyces dermatitidus
What thermal dimorphic fungi?
- primary infection is ASYMPTOMATIC in large majority of cases
- can lay dormant for years in lymphatic system
paracoccidiomycosis- paracoccidiodes brasiliensis
What thermal dimorphic fungi?
- outbreaks occur during dust storms and earthquakes
- 50% asymptomatic
- PROMINENT CAUSE OF FUNGAL MENINGITIS
coccidiomycosis- coccidioides immitus
What thermal dimorphic fungi?
-from soil as well as bird/bat droppings
histoplasmosis- histoplasma capsulatum
What is the “big picture” of thermally dimorphic fungi?
immune
- COMPETENT: self resolving
- COMPROMISED: high levels of mortality
Aspergillum species are an example of?
mold
Mucormycetes sp AND Rhizopus oryzae cause
mucormycosis
What is the major route of transmission of MOLDS?
via inhalation of the mold, which is ubiquitous in the environment
bacteria vs. fungi
bacteria: prokaryotes
fungi: eukaryotes
both have cell walls, but this has not proven to be an effective target for anti fungal drugs
The fungi cell wall is made up of _________ which allow for attachment of GLYCOPROTEINS
alpha and beta glucans
Mammalian vs. Fungi membranes
mammalian: cholesterol
fungal: ergosterol (flatter due to the addition of the 2 double bonds)
What are the 2 targets of antifungal medications?
- CYP 450 14 alpha demethylase
- squalene epoxidase
