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45 Cards in this Set

  • Front
  • Back
Light Microscopes
Brightfield: Uses 2 lenses (ocular and objective) to light up specimen

Darkfield: Condenser is modified so light is directed obliquely causing light to deflect off specimen. Specimen is bright and background is dark
UV light source
Fluorescent dyes absorb UV light at one wavelength and reflect it back at another
Specimens stained will glow against a dark background
Phase Contrast
Special objectives and condensers that allow light to refract differently through cell components which vary in intensity

Makes edges of the specimen more refractile
Confocal Laser Scanning
Used to create a 3D image of the specimen by optically sectioning the specimen with the use of lasers
Electron Microscope
Uses magnets and electron beams

2 Types
Transmission: Can cross section specimen
Scanning: Gives 3D look to the outside of the specimen
Gram Stain
Step 1: Crystal Violet (primary stain)

Step 2: Gram Iodine (Mordant)

Step 3: 95% Ethanol (Decolorizer)

Step 4: Safranin (Counterstain)
Acid Fast Stain
Used primarily to identify Mycobacterium sp.

Heat FIx
Carbol-fuchsin (Primary Stain)
HCl/Alcohol (Decolorizer)
Methyl Blue (Counterstain)
Capsule Stain
Skim Milk Medium

Heat Fix
Stain (Congo Red & Crystal Violet)

Background will stain as well as bacterial cell

Capsule will not stain leaving a halo around the cell
Liefson's Flagellar Stain
Mordant used in conjunction with Stain (encrusts on to flagella to increase thickness)
Endorespore Stain
Stain with Malachite Green (heat fix to allow penetration)
Secondary Stain with Safranin

Spores appear green
Vegetative cells turn pink/red
PEA Agar Media
Phenylethyl Alcohol Agar

Supports Gram (+) bacteria
Columbia CNA Blood Agar
Colistin, Naladixic Acid

Grows Gram (+) bacteria
Mannitol Salt Agar
Selective for Staphyloccus sp. (salt-tolerant)
Differential for Aureus (mannitol fermentor)
Tinsdale Medium
Thiosulfate-tellurite based medium

Primary isolation of Corynebacterium diptheria

Inhibits Gram (+)

Forms black colonies with gray halos
Egg Yolk Medium
Rich in phospholipids

CLOSTRIDIUM sp. with lecthinase activities are differentiated
Thayer-Martin Agar
Blood agar base

Antibiotics placed on dish to help control contamination

MacConkey Agar Medium
Selects for Gram (-)

Contains bile salts to inhibit Gram (+)

Specific for E. coli (turns red because it ferments lactose)
Hektoen Enteric Agar
Contains lactose

Helps to distinguish Salmonella, Shigella

Contains thiosulfate which Salmonella reduces to hydrogen sulfide
Xylose Lysine Desoxycholate Agar
Primary isolation of Salmonella vs. Shigella

Xylose fermentation, H2S production, and lysine decarboxylation distinguish Salmonella from Shigella
BG Agar
Bordet-Gengou agar

Selective for Bordetella pertussis (whooping cough)

Toxins produced by organism
BCYE Agar Medium
Buffered charcoal yeast extract agar

Selective for Legionella sp. (legionaires)
TCBS Agar Medium
Thiosulfate citrate-bile salts

Selective Differential medium for Vibrio sp. (Cholera)
Cefsulodin-Irgasan-Novobicin (CIN) Agar
Selective for Yersinia sp. (Plague)

Inhibits Gram (+ and -)

Appears as a red "bullseye" in each colony

48 hours @ 25 degrees C
Lowenstein-Jensen Agar
Egg based medium

Isolation of Mycobacterium sp.
Middlebrook Agar
Cultivate Mycobacterium sp.

More chemically defined than LJ
MES (Ureaplasma Agar)
Isolation of Ureaplasma urealyticum

Contains horse serum that supplies cholesterol to stabilize cell wall

Fried Egg colony morphology
Selective between Staph and Strep

Staph will be positive and bubble
Strep will be negative and not do anything
Differentiate between Staph aureus and other species
Gelatin Liquifaction test
Selective for bacterium that secrete gelatinases to liquify gelatin. Positive bacteria will degrade gelatin and it will be uniform throughout
Oxidase Test
Detects activity of the cytochrome oxidase enzyme

Selective for Neiserria
Indole Test
Detects activity of tryptophanase enzyme on tryptophan

End product indole reacts with Kovacs reagent turning it a red color

Selective for E. Coli
Urease Test
Detects activity of urease

Selective for Proteus sp.
Citrate Utilization Test
Ability to use citrate as sole carbon source

pH rises turning the bromthymol blue indicator from green to bright blue
Bile Esculin Test
Enterococcus (Group D streptococci)
DNAse Test
DNAse catalyzes depolymerization of DNA

Medium contains methyl green which binds to polymerized DNA

Exoenzyme breaks down the DNA into smaller fragments releasing it from the methyl green dye
Optochin Test
P disc

Selective for Streptococcus pneumoniae
Bacitractin Test
A disc

Differentiate group A Streptococci
Direct microscope examination
Treat specimen with KOH prep

Stain with either crystal violet or lactophenol cotton blue
KOH w/ calcofluor white
Fluorescent dye added to KOH prep that will bind to polysaccharides present in chitin and will fluoresce under light
Motility Test
Soft agar deeps are used

Stabbed with an inoculating needle
India Ink
Negative Stain

Used to see Cryptococcus neoformans (found in CSF and causes meningitis)
Periodic acid-Schiff stain
Used in detection of fungal elements in tissue specimens

Causes them to turn red/pruple to make them stand out
Grocott-Gomori Methenamine-Silver Nitrate Stain
Stains fungal elements black

Stains strains of Candida, Histoplasm, Blastomyces
Giemsa stain
Used for blood smears

Detects Histoplasma capsulatum in blood or bone marrow
Masson-Fontana Stain
Stains melanin in the cell wall a brown color