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Diagnostic Bacteriology > Media and Tests > Flashcards

Media and Tests Flashcards

0
Q

CHOC Agar Plate

A

Chocolate Agar
(Media)

KEY COMPONENTS

  • Nutritional base
  • Heated red blood cells or other suppliments

PURPOSE

  • Enriched and nonselective; cultivation of fastidious organisms including Haemophilus, Neisseria gohorrhoeae and Brucella
  • Nonfastidious organisms will also grow
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1
Q

Katy and Zahra

A

love Eric and Tosca

xoxo

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2
Q

CNA Plate

A

Colistin-Nalidixic Acid (CNA) Blood Agar
(Media)

KEY COMPONENTS
- Inhibitors: Colistin and nalidixic acid

PURPOSE
- Selective; isolation of gram-positive organisms including staphyloocci, streptococci, Listeria and Corynebacterium

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3
Q

CTA Plate

A

Cystine-Tellurite Agar
(Media)

KEY COMPONENTS
- Tellurite: Inhibits many organisms

PURPOSE

  • Selective and differential; isolation of Corynebacterium diphtheriae
  • Corynebacterium colonies are black (tellurite reduced to tellurium)
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4
Q

EMB Plate

A

Eosin-Methylene Blue (EMB) Agar
(Media)

KEY COMPONENTS

  • Inhibitors and pH indicators: Eosin and methylene blue
  • Carbohydrate: Lactose

PURPOSE

  • Selective and differential; isolation of nonfastidious gram-negative rods including enterics, Aeromonas and many nonfermenters
  • Inhibition of gram-positive organisms
  • Escherichia coli (strong lactose fermenter): Green sheen colonies
  • Lactose fermenters (Klebsiella and Enterobacter): Blue-black colonies
  • Nonlactose fermeters (Shigella and Salmonella): Colorless colonies
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5
Q

Loeffler Tube Medium

A

Loeffler Medium
(Media)

KEY COMPONENTS
- Growth enhancer: Serum

PURPOSE
- Enriched; used in the isolation of Corynebacterium diphtheriae

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6
Q

MAC Plate

A

Macconkey (MAC) Agar
(Media)

KEY COMPONENTS

  • Inhibitors: Bile salts and crystal violet
  • pH indicator: Neutral red
  • Carbohydrate: Lactose

PURPOSE

  • Selective and differential; inhibition of gram-positive organisms
  • Isolation of many nonfastidious gram-negative rods including the enterics, Pseudomonas, a number of other nonfermenters and most Vibrio
  • Lactose fermenters (Escherichia coli, Klebsiella and Enterobacter): Red to pink colonies surrounded by precipitated bile
  • Nonlactose fermenters (Salmonella, Shigella and Proteus): Colorless
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7
Q

MTM Plate

A

Modified Thayer-Martin (MTM) Agar
(Gonococcal Selective Agar)
(Media)

KEY COMPONENTS

  • Variety of nutrients
  • Inhibitors: Variety of antibiotics

PURPOSE

  • Enriched and selective; isolation of Neisseria gonorrhoeae and N. meningitidis
  • Supports the grown of Brucella specis and Franciscella tularensis
  • Other organisms may also grow on Gonococcal Selective Agar media
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8
Q

SBA Plate (or BAP)

A

Blood Agar Plate (BAP)
(Media)

KEY COMPONENTS

  • Nutritional base (e.g., trypticase soy agar)
  • Blood: Sheep (most often used), rabbit, horse or human

PURPOSE

  • Enriched, nonselective and differential (detection of hemolysis)
  • Cultivation of fastidious and nonfastidious organism including staphylococci, streptococci, gram-positive rods, most Neisseria species, enterics, nonfermenters, Vibrio species and many other organisms
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9
Q

TSA Plate or TSB Broth

A

Trypticase Soy Agar (TSA) or Broth (TSB)
(Media)

KEY COMPONENTS
- Digested soybeans and casein

PURPOSE

  • Nonselective nutrient medium; cultivation of fastidious and non-fastidious organisms including staphylococcci, streptococci and enterics
  • May be used as a base for blood agar
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10
Q

Bacitracin Disk

A

Bacitracin (A) Disk
(Test)

PRINCIPLE OR PROCEDURE

  • Some organisms are susceptible to 0.04 units of bacitracin
  • Inoculate agar for confluent growth; add disk
  • Incubate plate; measure zone

RESULTING APPEARANCE

  • Susceptible
    • Any zone
  • Resistant
    • No zone

SELECTED ORGANISM RESULTS

  • Susceptible
    • Micrococcus GAS
  • Resistant
    • Staphylococcus
    • Stomatococcus
    • GBS
    • Other beta-strep
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11
Q

Bile-Esculin Slant

A

Bile-Esculin
(Test)

PRINCIPLE OR PROCEDURE

  • 40% bile inhibits many organisms
  • Esculin > Esculetin + Glucose
  • Esculetin + Ferric ions > Black

RESULTING APPEARANCE

  • Positive
    • Black
  • Negative
    • No color

SELECTED ORGANISM RESULTS

  • Positive
    • Enterococcus
    • GDS
    • Listeria
  • Negative
    • Other strep
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12
Q

Bile Solubility Test

A

Bile-Solubility
(Test)

PRINCIPLE OR PROCEDURE

  • Pneumococcal autolysis is accelerated by bile
  • Plate method: Add bile to colonies
  • Tube method: Add bile to suspension of organisms

RESULTING APPEARANCE

  • Positive
    • Lysis
  • Negative
    • No lysis

SELECTED ORGANISM RESULTS

  • Positive
    • Pneumococci
  • Negative
    • Other strep
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13
Q

CAMP Test

A

CAMP
(Test)

PRINCIPLE OR PROCEDURE

  • GBS make CAMP factor
  • S. aureus make beta-lysin
  • Hemolysis enhanced when CAMP factor meets beta-lysin
  • Test organism streaked perpendicular to as S. aureus streak

RESULTING APPEARANCE

  • Positive
    • Enhanced hemolysis
  • Negative
    • No enhanced hemolysis

SELECTED ORGANISM RESULTS

  • Positive
    • GBS
  • Negative
    • Groups A, C, D, F and G strep
    • Enterococci
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14
Q

Catalase

A

Catalase
(Test)

PRINCIPLE OR PROCEDURE

  • H202 > H20 + O2
    • Place organism on the microscope slide and add drop of H2O2
  • H2O2 concentration used:
    • 3%-Aerobes and facultative anaerobes
    • 15%-Anaerobes

RESULTING APPEARANCE

  • Positive
    • Bubbles
  • Negative
    • No bubbles

SELECTED ORGANISM RESULTS
- Several (p. 456)

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15
Q

Citrate Test

A 
Citrate Utilization (Simmons Citrate Agar)
(Test)

PRINCIPLE OR PROCEDURE

  • Determines if organism can use citrate as sole source of carbon
  • Medium becomes alkaline of organisms grow
  • pH indicator: Bromthymol blue

RESULTING APPEARANCE

  • Positive
    • Blue
  • Negative
    • Green (color of uninoculated medium)

SELECTED ORGANISM RESULTS
- Several (p. 458)

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16
Q

Slide Coagulase

A

Coagulase-Slide (Bound Coagulase or Clumping Factor)
(Test)

PRINCIPLE OR PROCEDURE
- Fibrinogen (in plasma)
(down arrow next to) Cell-bound coagulase
Fibrin strands (connect cells)
- Prepare saline suspension of test organism on microscope slide
- Mix in drop of plasma

RESULTING APPEARANCE

  • Positive
    • Cell clumping
  • Negative
    • No clumping

SELECTED ORGANISM RESULTS

  • Positive
    • S. aureus
  • Negative
    • S. saprophyticus
    • S epidermidis
    • Most other Staphylococcus species
    • Micrococcus
17
Q

DNase Plate

A

Deoxyribonuclease (DNase)
(Test)

PRINCIPLE OF PROCEDURE

  • DNA > Nucleotides
    • Inoculate agar and incubate
  • Toluidine blue method:
    • DNA/toluidine blue = blue
    • Nucleotides/toluidine blue = pink
  • Methyl green method:
    • DNA/methyl green = green
    • Nucleotides/methyl green = clear
  • Hydrochloric acid (CHI) method: (HCI added to agar)
    • DNA/HCI = preciptate
    • Nucleotides/HCI = clear

RESULTING APPEARANCE

  • Positive
    • Toluidine blue: Pink
    • Methyl green: Clearing
    • HCI: Clearing
  • Negative
    • Toluidine blue: Blue
    • Methyl green: Green
    • HCI: Precipitate

SELECTED ORGANISM RESULTS

  • Positive
    • M. catarrhalis
    • S. marcescens
  • Negative
    • Neisseria
    • Enterobacter
17
Q

Tube Coagulase

A

Coagulase-Tube
(Test)

PRINCIPLE OR PROCEDURE
- Coagulase and coagulase-reacting factor
Fibrinogen > Fibrin clot (plasma)
- Add test organism to plasma tube and incubate for 4 hours at 35 degrees
- Hold negative tubes overnight at room temperature

RESULTING APPEARANCE

  • Positive
    • Clot
  • Negative
    • No clot

SELECTED ORGANISM RESULTS

  • Positive
    • S. aureus
  • Negative
    • S saprophyticus
    • S epidermidis
    • Micrococcus
    • Most other Staphylococcus species
19
Q

CTA Tubes (Glucose, Maltose, Lactose)

A

Cystine Trypticase Agar (CTA)
(Test)

PRINCIPLE OR PROCEDURE

  • Acid formed when carbohydrate is metabolized
  • Phenol red detects pH change

RESULTING APPEARANCE

  • Positive
    • Yellow
  • Negative
    • Red

SELECTED ORGANISM RESULTS
- See “Carbohydrate-rapid utilization” for Neisseria reactions (p. 456)

19
Q

Hippurate Hydrolysis Broth

A

Hippurate Hydrolysis
(Test)

PRINCIPLE OR PROCEDURE

  • Hippurate > (hippuricase over arrow) > sodium benzoate + glycine
  • Detect either Benzoate or glycine
  • Benzoate + Ferric chloride > Precipitate
  • Or, Glycine + Ninhydrin > Blue

RESULTING APPEARANCE

  • Positive
    • Benzoate: Precipitate
    • Glycine: Blue
  • Negative
    • Benzoate: No precipitate or clearance of precipitate
    • Glycine: No color

SELECTED ORGANISM RESULTS

  • Positive
    • GBS
    • Lisiteria
    • C. jejuni
  • Negative
    • Groups A, C, F and G streptococci
    • Entero cocci
    • Other species of Campylobeter
    • Helicobacter
21
Q

H2S Production

A 
Hydrogen Sulfide (H2S) Production
(Test)

PRINCIPLE OR PROCEDURE

  • Sulfur-containing amino acids
  • Or, inorganic sulfur compounds
    • (down arrow) Some organisms
    • (below that) H2S
  • H2S + Iron or Lead > Black

RESULTING APPEARANCE

  • Positive
    • Black
  • Negative
    • No color

SELECTED ORGANISM RESULTS
- Several (p. 463)

22
Q

Indole Spot

A

Indole-Spot
(Test)

PRINCIPLE OR PROCEDURE

  • Tryptophan > tryptophanase (over right arrow) > Indole
  • Indole + Reagent > Blue-green
  • Rub organism onto reagent-impregnated filter paper
  • Reagent: rho-Dimethylaminocinnamaldehyde

RESULTING APPEARANCE

  • Positive
    • Blue-green
  • Negative
    • No color

SELECTED ORGANISM RESULTS

  • Positive
    • Several (p. 463)
  • Negative
    • Several (p. 463)
23
Q

Indole Tube

A

Indole-Tube
(Test)

PRINCIPLE OR PROCEDURE

  • Tryptophan > tryptophanase (over right arrow) > Indole
  • Indole + Kovac’s or Ehrlich’s reagent > Red
  • Kovac’s and Ehrlich’s reagents: rho-Dimethylaminobenzaldehyde
  • Media tube incubated 18 to 24 hours before reagent added

RESULTING APPEARANCE

  • Positive
    • Red
  • Negative
    • Yellow or no color

SELECTED ORGANISM RESULTS

  • Positive
    • Several (p. 463)
  • Negative
    • Several (p. 463)
24
Q

MR Broth

A 
Methyl Red (MR)
(Test)

PRINCIPLE OR PROCEDURE

  • Glucose > Pyruvate > Acid (large amount)
  • Acid + Methyl red > Red (pH indicator)

RESULTING APPEARANCE

  • Positive
    • Red
  • Negative
    • No color

SELECTED ORGANISM RESULTS

  • Positive
    • Several (p. 466)
  • Negative
    • K. pheumoniae
    • Enterobacter
    • S. marcescens
25
Q

Motility Medium (without TTC)

A

Motility: Hanging Drop and Semisolid Agar
(Tests)

PRINCIPLE OR PROCEDURE

  • Hanging Drop: Microscopically examine wet mount of organism
  • Semisolid Agar: Stab organism into semisolid agar deep

RESULTING APPEARANCE

  • Positive
    • Hanging Drop: Active movement
    • Semisolid Agar: Diffuse haze of growth throughout medium
  • Negative
    • Hanging Drop: No active movement
    • Semisolid Agar: Growth only near stab line

SELECTED ORGANISM RESULTS
- Several (p.467)

26
Q

Novobiocin Disk

A

Novobiocin Disk
(Test)

PRINCIPLE OR PROCEDURE

  • Inoculate agar for confluent growth; add disk
  • Incubate plate; measure zone

RESULTING APPEARANCE

  • Susceptible
    • Equal to or greater than 16mm zone
  • Resistant
    • Less than 16mm zone

SELECTED ORGANISM RESULTS

  • Susceptible
    • S. epidermidis
    • Other coagulase-negative staph
  • Resistant
    • S. saprophyticus
27
Q

Nitrate Reduction

A

Nitrate Reduction
(Test)

PRINCIPLE OR PROCEDURE

  • Tube and disk tests available
  • Nitrate (NO3) > Nitrite (NO2) > N2 gas
  • Nitrate detected by adding sulfanilic acid (reagent A) and dimethyl-alpha-naphthylamine (reagent B); zinc added if no color appears
  • Mycobacterial test reagents: Hydrochloric acid (reagent #1), sulfanilamide (reagent #2), N-naphthylethylenediamine dihydrochloride (reagent #3) and zinc (if needed)

RESULTING APPEARANCE

  • Positive
    • Red after addition of reagents (nitrate present)
    • Colorless after reagents and zin (N2 present)
  • Negative
    • Red after reagents and zinc added (nitrate not reduced)

SELECTED ORGANISM RESULTS

  • Positive
    • Several (p. 468)
  • Negative
    • Several (p. 468)
28
Q

Nitrate Reduction

A

Nitrate Reduction
(Test)

29
Q

Optochin Disk

A

Optochin (P) Disk (Ethylhydrocupreine Hydrochloride)
(Test)

PRINCIPLE OR PROCEDURE

  • Inoculate agar plate for confluent growth with isolate
  • Place disk onto inoculated area
  • Incubate plate; measure zone

RESULTING APPEARANCE

  • Susceptible
    • Zone greater than or equal to cutoff (greater than or equal to14 mm for 6-mm disk)
  • Resistant
    • No zone

SELECTED ORGANISMS RESULTS

  • Susceptible
    • S. pneuumoniae
  • Resistant
    • Other strep
30
Q

Phenylalinine Tube (PHE) or (PDE)

A

Phenylalanine Deaminase
(Test)

PRINCIPLE OR PROCEDURE
- Phenylalanine
     (down arrow next to) Deaminase
     Phenylpyruvic acid
- Phenylpyruvic acid + Ferric chloride > Green

RESULTING APPEARANCE

  • Positive
    • Green
  • Negative
    • No color

SELECTED ORGANISM RESULTS

  • Positive
    • Proteuus
    • Providencia
    • Morganella
  • Negative
    • Several (p. 471)
31
Q

Oxidase Test

A

Oxidase
(Test)

PRINCIPLE OR PROCEDURE
- Tetramethyl-rho-phenylenediamine dihydrocholoride (oxidase reagent)
     (down arrow next to) Cytochrome
     (same down arrow next to) Oxidase
     Indophenol

RESULTING APPEARANCE

  • Positive
    • Dark purple or blue-black
  • Negative
    • No color

SELECTED ORGANISM RESULTS

  • Positive
    • Several (p. 469)
  • Negative
    • Several (p. 469)
32
Q

PYR Test

A

PYR (Pyrrolidonyl-beta-naphthylamide)
(Test)

PRINCIPLE OR PROCEDURE
- L-phyrrolidonyl-beta-naphthylamide
(down arrow next to) L-pyroglutamyl aminopeptidase
(below that) Free beta-naphthylamine
- N,N dimethylaminocinnamaldehyde add to detect beta-naphthylamine

RESULTING APPEARANCE

  • Positive
    • Red
  • Negative
    • No color change

SELECTED ORGANISM RESULTS

  • Positive
    • GAS
    • Enterococcus
    • Other gram-positive bacteria may be (+)
  • Negative
    • Other strep
33
Q

ALA Porphyrin Test

A

Porphyrin
(Test)

PRINCIPLE OR PROCEDURE
- Determines if a Haemophilus isolate requires X factor
- Aminolevulinic Acid (ALA)
(down arrow)
Porphobilinogen
(down arrow)
Porphyrins
(down arrow)
Hemin
- Porphobilinogen detected by Kovac’s reagent (rho-dimethylaminobenzaldehyde)
- Porphyrins detected by Wood’s lamp (ultraviolet light)

RESULTING APPEARANCE

  • Positive
    • Kovac’s:
      • Red color indicates organism does not need X factor
      • No color change indicates organism requires X factor
    • Wood’s light:
      • Fluorescence indicates organism does not need X factor
      • No fluorescence indicates organism needs X factor
  • Negative
    • None listed

SELECTED ORGANISM RESULTS

  • X factor required: H. influenzae, H. haemolyticus, H. ducreyi and H. aphrophilus (required for primary isolation)
  • X factor not required: H. parainfluenzae and H. parahaemolyticus
34
Q

6.5% NaCl Broth

A 
Salt Tolerance (6.5%)
(Test)

PRINCIPLE OR PROCEDURE

  • 6.5% salt inhibits many organisms
  • Inoculate broth with organism

RESULTING APPEARANCE

  • Positive
    • Turbidity or acid pH
  • Negative
    • No turbidity or pH change

SELECTED ORGANISM RESULTS

  • Positive
    • Enterococci
  • Negative
    • GDS not enterococci
    • Other strep
35
Q

Satellite Test

A

Satellite
(Test)

PRINCIPLE OR PROCEDURE

  • Satelliting organism uses excess nutrients produced by S. aureus
  • Organism inoculated onto BAP
  • S. aureus then streaked through inoculated area

RESULTING APPEARANCE

  • Positive
    • Tiny colonies growing near staph streak
  • Negative
    • No tiny colonies growing near staph streak

SELECTED ORGANISM RESULTS

  • Positive
    • Satelliting strep (A. defectivus and A. adiacens)
    • Haemophilus
  • Negative
    • None listed
36
Q

Spore Stain

A 
Spore Test (Ethenol Method)
(Test)

PRINCIPLE OR PROCEDURE
- Ethanol + (down arrow next to) Vegetative bacteria
> Death
- Ethanol + Spores
> Spores
- Treat broth culture with ethanol
- Subculture untreated and ethanol-treated broths onto anaerobe blood agar (anaBAP)

RESULTING APPEARANCE

  • Positive
    • Spore formes: Growth on both anaBAPs
    • Non-spore formers: Growth on ana BAP inoculated with untreated broth; no growth on anaBAP inoculated with treated broth
  • Negative
    • Some clostridia rarely form spores and may not survive the spore test

SELECTED ORGANISM RESULTS

  • Positive
    • Most clostridia
  • Negative
    • Non-spore formers
37
Q

TSI Slants

A

Triple Sugar Iron (TSI) Agar
(Test)

PRINCIPLE OR PROCEDURE

  • TSI has essentially the same purpose as Kligler iron agar (KIA)
  • TSI and KIA inoculated and read in same manner
  • TSI detects glucose, lactose and sucrose
  • See “Kliger iron agar” for more info

RESULTING APPEARANCE
- None listed

SELECTED ORGANISM RESULTS

  • TSI and KIA reactions are the same for most organisms; reactions are different for lactose (O) and sucrose (+) organisms
  • S. marcescens and Y. enterocolitica: KIA = K/A; TSI = A/A
  • P. vulgaris: KIA = K/A, H2S; TSI = A/A, H2S
38
Q

VP Broth

A

Voges-Proskauer (VP)
(Test)

PRINCIPLE OR PROCEDURE
- Glucose
     (down arrow)
     Pyruvate
     (down arrow)
     Acetoin (acetyl-methyl carbinol)
- Acetoin + alpha-Naphthol + 40% KOH > Red

RESULTING APPEARANCE

  • Positive
    • Red
  • Negative
    • No color change

SELECTED ORGANISM RESULTS

  • Positive
    • K. pneumoniae
    • Enterobacter
    • S. macescens
    • Some P. mirabilis
  • Negative
    • Several (p. 477)
39
Q

X and V Growth Factor

A

X, V and XV Factor Disks
(Test)

PRINCIPLE OR PROCEDURE

  • Test organism inoculated onto trypticase soy agar and Mueller-Hinton agar, which lack X factor (hemin) and V factor (NAD)
  • Paper disk with X, V or XV placed onto inoculated area

RESULTING APPEARANCE

  • Positive
    • Growth around disk
  • Negative
    • No growth

SELECTED ORGANISM RESULTS

  • X factor only required: H. ducreyi and some H. aphrophilus
  • V factor only required: H. parainfluenzae and H parahaemolyticus
  • X and V factor required: H. influenzae and H. haemolyticus
40
Q

MSA Plate

A

Inhibitor: 7.5 salt
pH indicator: phenol red
Mannitol

Selective and differential for isolation of S. Aureus
Positive fermentation turns media yellow.

Diagnostic Bacteriology (1 decks)

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