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Practical 1
Actinomycetes, Mycobacterium, and Medical Mycology
101
Microbiology
Graduate
02/05/2013

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Cards

Term
Which yeast are germ tube positive?
Definition
C. albicans and C. dublinenses
Term
Which yeast is germ tube negative?
Definition
C. glabrata
Term
Which yeast is India Ink positive?
Definition
C. neoformans
Term
What makes C. albicans/dublinenses germ tube positive?
Definition
psuedohyphae
Term
What makes C. neoformans India Ink positive?
Definition
Capsule/Halo
Term
What differentiates Epidermophyton from the other dermatophytes?
Definition
Epidermophyton has thin and smooth macrocondidia growing directly from septate hyphae
Term
What differentiates Microsporom from the other dermatophytes?
Definition
Microsporum has rough and turbulent macrocondidias with a spindle shape, growing from multiseptate hyphae
Term
What differentiates Trichophyton from the other dermatophytes?
Definition
Trichtophyton have microcondidia growing directly from the hyphae
Term
What differentiates Penicillium from Aspergillus?
Definition
Penicillium has a condidiaphore which gives rise to thin finger-like phialides
Term
What differentiates Aspergillus from Penicillium?
Definition
Aspergillus has condidiaphores which give tise to a vesicle which has phialides on top of it
Term
What are the names of the three dimorphic fungi?
Definition
Blastomyces dermatitdis, Coccoidiodes immitis, and Sporothrix schenkeii
Term
What makes the yeast form of Blastomyces dermatitdis special?
Definition
grows at 37 C, large, broad-based, unipolar yeast-like cell
Term
What makes the yeast form of Coccoidiodes immitis special?
Definition
grows at 37 C, large, thick, contains endospores
Term
What makes the yeast form of Sporothrix schenkeii special?
Definition
grows at 37 C, oval to cigar shaped yeast cells, single-multiple buds from one cell
Term
What makes the mold form of Blastomyces dermatitdis special?
Definition
grows at 25 C, septate hyaline hyphae, unbranched, short condidiophores at right angles
Term
What makes the mold form of Coccoidiodes immitis special?
Definition
grows at 25 C, barrel-like anterospores with thin septate hyphae
Term
What makes the mold form of Sporothrix schenkeii special?
Definition
grows at 25 C, septate hyaline hyphae, condidiophores and conidia, looks like roses growing off the hyphae
Term
Name the dematiacious molds
Definition
Alternaria spp. and Curvularia spp.
Term
What differentiates Alternaria spp. from Culvularia spp.?
Definition
Alternaria spp. appears with transverse and longitidinal sepations in the condidia
Term
What differentiates Culvularia spp. from Alternaria spp.?
Definition
Culvularia spp. appears with curved macrocondidia
Term
What color is a positive modified kinyoun stain?
Definition
Red
Term
What color is a positive kinyoun stain?
Definition
Red
Term
What color is a positive fluorescent stain?
Definition
Gold
Term
What color is a negative modified kinyoun stain?
Definition
blue/green
Term
What color is a negative kinyoun stain?
Definition
blue/green
Term
What color is a negative fluorescent stain?
Definition
black
Term
Why do we use Kinyoun stains?
Definition
Kinyoun stains are used for bacteria which do not take up the Crystal Violet stain well
Term
Why do we use modified kinyoun stains?
Definition
some bacteria do not take up the crystal violet well, and do not have enough mycolic acid in their walls to hold the primary stain during decolorization, the decolorizer in modified kinyoun is less potent
Term
How do you do a modified kinyoun?
Definition

3 minutes with carbol fuchsin

rinse

decolorize with 1% sulfuric acid

rinse

Counter stain for 30 seconds with methylene blue, malachite green or brilliant green

rinse

air dry 

Term
Describe Actinomyces
Definition
endogenous strain, obligate anaerobe, causes lumpy jaw and IUD infections, sulfur granules present in tissue, molar tooth colony, modified kinyoun negative
Term
Describe Nocardia
Definition
obligate aerobe, causes pulmonary and skin/tissue infections (mycetomas), colonies appear white, tan, orange, dry, wrinkled, and chalky, modified kinyoun positive
Term
Describe Streptomyces
Definition
causes skin infections (mycetomas) and pulmonary diseases, colonies appear waxy, modified kinyoun negative
Term
How do you do a kinyoun stain?
Definition
5 minutes with carbol fuchsin
rinse with tap water
2 minutes with 3% decolorizer
rinse
1-3 minutes with methylene blue
rinse
air dry
Term
How do you do a fluorescent stain?
Definition
15-20 minutes with auramine-rhodamine stain
rinse
2-3 minutes with 3% HCl decolorizer
rinse
2-4 minutes with potassium permanganate
rinse
air dry
Term
Describe mycobacterium tuberculosis
Definition
slow grower, nonpigmented, tan, buff, dry and rough on plate, cord formation on stained smear, niacin positive, fluorescent and kinyoun positive
Term
Which mycobacterium are photochromagens
Definition
M. kansasii and M. marinum
Term
When does a photochromagen produce pigment?
Definition
upon exposure to light
Term
Which mycobacterium are scotochromagens?
Definition
M. gordonate
Term
When does a scotochromagen produce pigment?
Definition
always
Term
Describe M. fortuitum
Definition
rapid grower, buff, moist colonies
Term
Describe M. avium-intracellulare
Definition
rapid grower, nonphotochromagen
Term
describe M. leprae
Definition
no growth in routine agar, found on foot pads of armadillos
Term
Which other organisms can positive false positives in AFB cultures?
Definition
bacteria, nocardia, and yeast
Term
What is the general description of mycobacterium?
Definition
pleomorphic beaded gram positive rods, non motile, non branching, non spore forming, strict aerobes, varying growth rate, environmental contaminants (except MTB)
Term
What are the staining methods for AFB?
Definition
Ziehl Nelson, Kinyoun, and Fluorescent
Term
What is different between the light microscope and the fluorescent microscope?
Definition
Light source comes from above (fluorescent) and below in the light. The fluorescent light hits the molecules and excites them which causes them to give off light as they come back down to ground state
Term
What media is mycobacterium cultured on?
Definition
Lowenstein Jensen agar
Term
What precautions should you take when working with AFB?
Definition
Negative pressure room, biological safety cabinet and face mask, saftey cups for centrifugation, splash-proof discard containers, disposable inoculating needles, disposal of waste
Term
What are acceptable specimens for AFB culturing?
Definition
respiratory specimens (3 days worth), urine (centrifuge before processing), stools (direct smear screen), bone and tissue (ground up), blood and fluid (mycolyic bottle or isolator tube)
Term
What do you use to decontaminate AFB specimens?
Definition
1:1 ratio of specimen to NALC with NaOH
Term
Describe the steps in processing AFB specimens?
Definition
add NALC and NaOH
Vortex, let sit for 20 min
add phosphate buffer
concentrate with centrifugation for 15 min
pour off supernatent
inoculate media, make 2 smears, heat fix to slide
Term
Describe LJ agar
Definition
egg based
Term
Describe Middlebrook agar?
Definition
agar or broth based
Term
In which environment do you incubate LJ slants?
Definition
dark, Co2
Term
4 ways of identifying mycobacteria
Definition
runyoun classification (growth rate), chromagen (pigment), biochemical testing, or DNA probes/PCR
Term
How does Mass Spectrophotmetrey identify mycobacteria?
Definition
analysis of proteolytic peptides
Term
How does HPLC identidy mycobacteria?
Definition
quantification of mycolic acids
Term
What are the 5 primary anti-TB drugs?
Definition
Isoniazid, Rifampin, Ethambutol, Streptomycin, and Pyrazinamide
Term
What are the 3 methods of susceptiblity testing for multi-drug resistant TB
Definition
agar with antibiotics, broth dilution (MIC) and PCR
Term
What is the general description of Actinomycetes?
Definition
beaded, branching, filamentous, gram positive rods
Term
5 ways to identify actinomycetes
Definition
gram positive rod, branched filaments, grows on BAP, CAP, LJ and SAB (3-6 days), decomposition of casein and DNA sequencing
Term
Yeast on a gram stain are
Definition
gram positive
Term
What is KOH prep used for?
Definition
breaks down keratin and releases it into solution
Term
How do you identify C. neoformans?
Definition
india ink positive, urease positive on urea slant or rapid latex antigen test on CSF or serum
Term
What are mycelum?
Definition
long structures, intertwined on SAB agar, characteristic of fungal cultures
Term
How do you identify C. glabrata?
Definition
RAT test positive (rapid assimilation trehelose)
Term
How do you identify yeast?
Definition
Rapid ID or automated ID based on sugar assimilation
Term
How do you identify mold?
Definition
Structures and touch prep
Term
What is in touch prep?
Definition
lactophenol cotton blue stain
Term
how do perform a slide culture?
Definition
Take a circle of sab dex agar
set on glass side in petri dish (with toothpicks and moist towel)
inoculate agar with mold via notches on side corners
place cover slip on top
incubate
remove cover slip, stain and look for structures
Term
What is PNA fish?
Definition
peptide nucleic acid FISH, tag and attach probe to molecular structure
Term
What is unique about the structure of C. albicans?
Definition
chlamydospores and psuedohyphae
Term
How do you differentiate between Geotrichum spp. and trichosporon spp?
Definition
Geotrichum shows individual artherospores with septate hyphae, Trichosporon shows blastocondidia
Term
What are the three Zygomycetes?
Definition
Rhizopus, Mucor and Absidia
Term
What is characteristic of Rhizopus?
Definition
rhizoids at the bottom of sporeangiophores
Term
What is characteristic of Mucor?
Definition
no rhizoids
Term
What is characteristic of Absidia?
Definition
Rhizoids in between sporeangiophores
Term
[image]
Definition
Cryptococcus neoformans, india ink
Term
[image]
Definition
C. albicans, wet mount
Term
[image]
Definition
Geotrichum spp. Touch Prep
Term
[image]
Definition
Trichosporon sp. Touch prep
Term
[image]
Definition
Alternaria sp.
Term
[image]
Definition
Curvularia sp.
Term
[image]
Definition
Aspergillus sp.
Term
[image]
Definition
Penicillium sp.
Term
[image]
Definition
Epidermophyton
Term
[image]
Definition
Microsporum sp.
Term
[image]
Definition
Trichophyton sp.
Term
[image]
Definition
Trichophyton sp.
Term
[image]
Definition
Blastomyces dermatitidis, yeast
Term
[image]
Definition
Blastomyces dermatitidis, mold
Term
[image]
Definition
Sporothrix schenkeii - mold
Term
[image]
Definition
Rhizopus
Term
[image]
Definition
Absidia
Term
[image]
Definition
Mucor
Term
[image]
Definition
Aspergillus
Term
[image]
Definition
C. Albicans
Term
[image]
Definition
Penicillium
Term
[image]
Definition
Aspergillus
Term
[image]
Definition
Rhizopus
Term
[image]
Definition
Germ Tube Negative
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