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81 Cards in this Set
- Front
- Back
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Light Microscopes - Brightfield
The specimen is illuminated by a beam of what kind of light? Focused by a substage lens called? |
1.Tungsten light
2. Condenser |
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Light Microscopes - Darkfield
specimen looks |
specimen is bright against a dark background
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Light microscope - Fluorescent
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fluorescent dyes absorb UV light at 1 wavelength and reflect back light at different wavelength
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Light Microscope - Phase Contrast
refract light through the cell components which vary in |
density and thickness
- edges of the specimen more refractile - used a lot in urine specimen |
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Light Microscope - DIC
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separates the light into 2 beams which recombine and are out of phase with each other
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what form of light microscope forms a 3D image via light?
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Differential interference contrast
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what form of light microscope forms a 3D image via optically sectioning the specimen with lasers?
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Confocal laser scanning
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Instead of using lenses, the electron microscope uses
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magnets
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instead of light, the electron microscope uses
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electron beams
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In gram staining what is the primary stain?
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crystal violet
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what fixes crystal violet into the cell wall
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Gram's iodine (mordant)
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What does 95% ethanol do in gram stain
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1. destains gram-negative bacteria
2. dehydrates and locks in the crystal violet with gram-positive bacteria |
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What is the counter stain in gram staining?
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safranin
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what step in gram staining is the only step where gram negative and gram positive act different?
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Step3 - Decolorizing agent
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Step 1 of gram stain and the reagent used
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primary stain
- crystal violet |
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Step 2 of gram stain and the reagent used
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mordant
-Gram's iodine |
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Step 3 of gram stain and the reagent used
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decolorizing agent
- 95% alcohol |
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Step 4 of gram stain and the reagent used
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counterstain
- safranin |
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Acid Fast Stain is used primarily to ID ?
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Mycobacterium
(high content of mycolic acid) |
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what is the 1st step in acid fast stain?
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heat fix thin film of microorganisms
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what is the 2nd step in acid fast stain?
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flood slide with carbofuchsin
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what is the 3rd step in acid fast stain?
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rinse, flood slide with acid alcohol
(to destain non-acid fast microorganisms) |
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what is the 4th step in acid fast stain?
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rinse, counterstain with methylene blue
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what is the primary stain in the acid fast stain?
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carbol-fuchsin (red)
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What is the counterstain in Acid fast stain?
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Methylene Blue
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what will a capsule stain look like?
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capsule will not stain, leaving a halo around the bacterial cells
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what stain is used in staining endospores?
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malachite green
(use steam heat to allow penetration) |
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Endospre stain -
1. Spores will appear ? 2. Vegetative cells will appear? |
1. green
2. pink/red |
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What is the general purpose of culture media?
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- grow most microorganisms
- do not contain growth inhibitors |
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Most common culture media?
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blood agar medium
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gelling medium
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agar
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liquid culture media
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broths
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selective media
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favor growth of certain groups and favor others
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PEA agar
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inhibits gram-negative microorganisms (use when looking for gram positive)
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differential media
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disting microorganisms having a defined metabolic activity over others that lack it
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Simmon Citrate Agar
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pH indicator that turns from green to blue when citrate is used as the sole carbon source
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Mannitol Salt Agar is an example of
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selective/ differential media
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mannitol salt agar is selective:
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7.5% salt inhibit all but staphylococci
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mannitol salt agar differential:
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staphylococcus aureus ferments mannitol
(pH turn from red to yellow) |
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Phenylethyl alcohol agar with blood supports? inhibits?
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supports- gram positive
inhibits- gram negative |
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Columbia CNA blood agar
support? inhibit? |
supports- gram postive
inhibits- gram negative |
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Tinsdale Medium is the primary isolation medium for
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Corynebacterium diptheriae
(form black colonies surrounded by dark-gray halos) |
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Egg Yolk Medium used to detect what type of microorganisms?
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Clostridium
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Thayer-Martin Agar is selective for
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Neisseria gonorrhoeae
Neisseria Meningitidis |
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MacConkey Agar Medium "Mac" select for
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Gram-negative bacteria
-ferment lactose (E.Coli) change to dark pink to red |
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"Mac" contains ___ ____ that inhibit grams positive bacteria
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bile salts
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Hektoen Enteric Agar is used to differentiate between ?
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Salmonella and Shigella
(isolate bacteria in enterobacteriaceae family) |
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Hektoen Enteric Agar contains thiosulfate which
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salmonella reduces to hydrogen sulfide (black precipitate)
(if not black then its shigella) |
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Xylose Lysine Desoxycholate agar primary isolation of
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salmonella and shigella
-H2S production in Salmonella and its black |
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"MAC" agar gram -negative ferment
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lactose (E.Coli)
changes the neutral red indicator to a dark pink/red |
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Eosin Methylene blue Agar (EMB) favor
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favor - gram negative enterics
(contains lactose which allows differentiation btwn lactose fermenters and nonfermenters) |
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Hektoen Enteric Agar isolates
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Enterobacteriaceae family
particularly salmonella and shigella |
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Hektoen Enteric Agar contains ___ which salmonella reduces to hydrogen sulfide
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thiosulfate
(black precipitate) |
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Xylose Lysine Desoxycholate Agar primary isolation of
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salmonella and shigella
(H2S production distinguishes salmonella from shigella ..get back preciptate) |
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Bordet- Gengou (BG) agar medium is selective for
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bordetella pertussis
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Buffered Charcoal Yeast Extract Agar (BCYE) is selective for
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Legionella
(key ingredient is alpha-ketoglutarate) |
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Thiosulfate Citrate-bile salts (TCBS) Agar medium is selective and differential for
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Vibrio sp.
(causative agents for cholera) |
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Cefsulodin-Irgasan-Novobiocin (CIN) agar is selective for
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Yersinia sp. (Plague)
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Lowenstein-Jensen Agar is an ___-based medium
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Egg
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Lowenstein-Jensen Agar contaminants inhibited by
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malachite green
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Lowenstein-Jensen Agar isolation of
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Mycobacterium sp
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MES (Ureaplasma Agar) used for isolation of
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Ureaplasma Urealyticum
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MES (Ureaplasma Agar) contains
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Horse serum
- supplies cholesterol needed for stabilizing these microorganisms which lack a cell wall Urea |
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Catalase
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enzyme breaks down hydrogen peroxide into water and oxygen
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Catalase
Staphylococcus- Streptococcus- |
staphylococcus- positive
streptococcus - negative |
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Coagulase
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ability to bind fibrinogen causing agglutination of microorganisms
(if positive staphylococcus aureus) |
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Oxidase Test (Neisseria) detects activity of the
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cytochrome oxidase enzyme
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Oxidase Test (Neisseria) purple end product
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indophenol
(end product purple if oxidase positive) |
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Indole Test (escherichia coli) detects activity of the
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tryptophanase enzyme on tryptophan
turn red if positive |
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Urease Test produce
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ammonia which changes the pH creating a color change to pink
-Key characteristic or proteus |
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Citrate Utilization Test
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ability to use citrate as sole carbon source
- Increase in pH turing bromthymol blue indicator from green to blue |
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Bile esculin test used in
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Group D streptococci can hydrolyze esculin
(by products react with iron salts to changes the color from orange to black) |
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Optochin Test P disc is the presumptive test for
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streptococcus pneumoniae
- is optochin sensitive - alpha hemolytic zones around colonies) |
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A disc is used to
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differentiate group A streptococci from other groups of beta-hemolytic streptococci
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Fungal studies use what type of solution?
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KOH
- direct microscopic examinations |
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KOH is used with ________ (fluorescent dye) for fungal studies
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calcofluor white
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Indian Ink (fungal studies) is used to examine
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CSF for encapsulated yeast ( Cryptococcus neoformans)
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Grocott-Gomori Methenamine-Silver Nitrate stain
-stains fungal elements____ -used to stain fungi such as : |
1. Black
2. Candida, Histoplasma, Blastomyces |
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Giemsa Stain detects
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histoplasma capsulatum in blood or bone marrow
( stains yeast a purple-blue surrounded by clear halo) |
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Masson - Fontana Stain
stains |
melanin in the cell wall a brown color
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PLFA can be used to determine
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viability
-dead vs. live (phospholipids degrade after cell death) |
