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<1mm colony size is considered…
pinpoint
1-2mm colony size is considered
small
2-3mm colony size is considered
medium
>3mm colony size is considered
large
transparent colony means it is
clear
translucent colony means it is
nearly clear
a frosted appearance to a colony is considered
opaque
an iridescent colony means
it changes color as the plate is tilted
what is an example of a bacteria whose colonies are iridescent
pseudomonas aeruginosa
what does it mean for a colony to be butyrous
buttery consistency
what does it mean for a colony to be friable
it is brittle and falls apart
what does it mean for a colony to be viscous
it sticks to the loop
what does it mean for a colony to be mucoid
it is slimy and strings from the loop
what is beta hemolysis
clear halo around the colony
what is alpha hemolysis
green halo around the colony
what is gamma hemolysis
no hemolysis
what color is MAC lactose fermenter
pink
what color is MAC non lactose fermenter
yellow or no color
what bacteria is known for smelling like grapes
pseudomonas aeruginosa
what bacteria is known for smelling like bleach
Eikenella corrodens
what is a direct gram stain
stained bacteria taken directly from the colony
what is an indirect gram stain
stained bacteria that comes from a plate after growth
what kind of media should you not take bacteria from for an indirect gram stain
selective
fixing a slide ensures
all vegetative organisms are killed
preservation of the bacteria from changes
improved adhesion to the slide
improved penetration of the stain into the cell wall
what is the best way to fix a slide
flooding the slide for 1 minute with 95% methanol
flooding the slide with 95% methanol is best for
preserving cell morphology
best for morphology of WBC, RBC and epithelial cells
best for bloody specimens
what is a simple stain
one dye or stain is used so everything on the smear is stained the same
what is an example of a simple stain
methylene blue
what is a downside of using simple stain
we can only determine the cell shape
what is differential stain
separates bacteria into different groups depending on staining properties
examples of differential stains include
Gram stain , Acid Fast stain
what is acid fast stain used for
to demonstrate bacteria with mycolic acids in the cell wall
gram stains on acid fast bacteria are either…
gram positive, gram ghosts or gram neutral
What kind of stain in Ziehl-Neelsen
acid fast
what makes Ziehl-Neelsen stain different from Kinyoun
ZN requires heat where Kinyoun does not
what do positive acid fast bacteria look like after staining with Ziehl-Neelsen
red bacteria with a blue background
what is the counter stain for Ziehl-Neelsen
methylene blue or malachite green
how is kinyoun different from Ziehl-Neelsen
has a higher phenol concentration
what kind of stain is Kinyoun
acid fast
what kind of stain is Auramine rhodamine
acid fast
what kind of stain is Acridine orange
special
what does acridine orange stain for
binds non specifically with nucleic acids
what can acridine orange detect
mycoplasma
what kind of stain is auramine-rhodamine
special
what does auramine-rhodamine stain for
binds non specifically to mycobacteria
what kind of stain is Calcofluor white
special
what does calcofluor white stain for
direct detection of fungus
what kind of stain is immunofluorescence
special
what does immunofluorescence stain for
antibody/antigen attachment
what bacteria is immunofluorescence good for
chlamydia trachomatis
what does dark field microscopy detect
spirochetes such as treponema pallidum
what are wet mounts
where microbes are visualized in a living state to see motility
what are negative stains
the background of the smear is colored instead of the bacteria
what is used in negative stains
India ink
what is a bacteria that uses negative staining
cryptococcus neoformans in CSF
What can not be detected with a gram stain
intracellular pathogens
can not be detected by a gram stain
organisms without a cell wall
what can not be detected by a gram stain
organisms with insufficient dimensions to be resolved
what is an example of a bacteria that is an intracellular pathogen
chlamydia spp.
what is an example of a bacteria without a cell wall
mycoplasma spp.
what is an example of an organism with insufficient dimensions to be resolved
spirochetes
what is the primary stain in a gram stain
crystal violet
what is a trapping agent in a gram stain
bonds alkaline dye to the cell wall
what is an example of a trapping agent in a gram stain
Gram’s or Lugols iodine
what is an example of a decolorizer in a gram stain
acetone and/or alcohol
what is the most important step during the gram stain process
decolorizer
what is the secondary stain in the gram stain
safranin - neutral red
a direct gram stain can not be performed on
feces
you can not perform a direct gram stain on
throat swabs
direct gram stains can not be performed on
nasopharyngeal specimens
what causes the crystal violet stain to run out of gram negative organisms
higher lipid content in the cell wall making them more porous
what causes crystal violet to be trapped in gram positive organisms
thicker cell walls
over decolorization causes gram positive organisms to
lose crystal violet stain and appear red/pink
under decolorization causes gram negative organisms to
not have crystal violet removed resulting in a purple appearence
when observing cells under a direct gram stain, phagocytes are an indicator of
inflammation
when observing cells under a direct gram stain, epithelial cells are an indicator of
possible contamination
do you see host cells in an indirect gram stain
NO
what type of gram stain is recorded, but not reported to the doctor
indirect
gram positive organisms will appear pink if
cell wall is damaged
affected by antibiotics
old age
autolytic enzymes
over decolorization
Note 
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