Flashcards in Intro to Mycology Deck (39):
What composes the cell wall of fungi?
Glucan and chitin (glucosamine), and ergosterol
What composes the cell wall of bacteria?
What makes treatment difficult for fungi?
they resemble human cells, eukaryotes
What is a single cell yeast?
What is a bud from asexual reproduction?
What are products of sexual reproduction (less common)?
These form from elongation of blastoconidia (constrictions).
These are the beginning of true hyphae (no constrictions) .
If molds look fuzzy or wooly macroscopically and have entertwined hyphae this is also known as what?
Mass of mycelia
These are crosswalls that are present in hyphae.
This means crosswalls are absent (or sparse), aka coenocytic
This means hyphae growth within the surface of the medium (agar).
These hyphae filaments extend above the agar surface (on top).
These hyphae are nonpigmented or slightly pigmented.
These hyphae are dark or black (melanin) on the reverse side of the colony.
These hyphae break or fragment; look like floating logs in a river
These are round and thick-walled conidia that form directly within or at the ends of hyphae; example includes Candida albicans
This is a specialized part of the hyphal filament that gives rise to conidia.
What stains hair, skin, and nails and also breaks down keratin leaving an outline of the hyphae?
What stains patient specimens, chitin, using a fluorescent dye?
What stains the capsule of Cryptococcus in patient specimens?
In this patient specimen stain, yeast stains blue.
All yeasts and hyphae turn brown-black with this patient specimen stain.
GMS (Gomori's Methenamine Silver)
What is the best way to culture blood and bone marrow?
Isolator (lysis centrifugation)
What is the best way to culture hair, skin, and nails (dermatophyte infections)?
scrape outer edge of skin lesion and use 10-20% KOH
What two types of fungal isolation media do we use most commonly?
sabouraud dextrose agar (SDA or SAB) and potato dextrose (PDA) or Potato Flake (PFA)
What are the incubation requirements for molds and yeast?
Describe what molds look like macroscopically?
fluffy and fuzzy (aerial mycelia)
Describe what yeast looks like macroscopically?
usually creamy (sometimes dry)
What is the best method to view molds?
slide cultures with LPCB (lactophenol cotton blue)
why do we see more recent cases of mycoses?
the host has changed, not the fungi
How do people get mycoses?
inhalation of mold condida most common way of mold infections
Describe fungal treatment, including common azole.
many agents are toxic to patients because cell wall structure so similar; common cause of renal toxicity= Amphotericin B
What is the most common antimicrobial susceptibility test of fungi?
broth dilution (standard method)
Most yeast like fungi stain gram ______.
Why do we use a class II safety hood when handling these organisms?
airborne conidia can cause infections with inhalation
What is CSAB (SAB with antimicrobials) used in lab?
Cyclohexamide inhibits bacteria and environmental fungi
What agar is used to examine yeast phase of dimorphics?
BHI with blood