Culture Media Flashcards

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1
Q

Origin of Agar

A

Seaweeds (red algae of galidium and gracilaria)

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2
Q

Composition of agar

A

Polysaccharide - Agarose and Agaropectin

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3
Q

Nutritional value of Agar

A

None

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4
Q

Melting and Solidifying temperature of Agar

A

Melts >98°C
Solidify <42°C

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5
Q

Concentration of Solid, semisolid and Firm agar

A

Solid - 2% agar
Semisoild - 0 5% agar (Motility testing)
Firm - 5-6% agar (inhibit swarming motility - Proteus)

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6
Q

Simple media/ Basal medium / Basic medium

A

Only Non fastidious organisms will grow
Peptone water

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7
Q

Composition of Peptone water

A

Peptone - 1%
Nacl - 0.5%
Water

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8
Q

Nutrient broth Composition

A

Peptone water + 1% meat extract

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9
Q

Nutrient agar composition

A

Nutrient broth + 2% Agar

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10
Q

Enriched medium used to grow

A

Used to grow fastidious organisms
Egg/blood/serum is added to provide extra nutrition

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11
Q

Enriched medium includes

A

Blood agar
Chocolate agar
Loeffler’s serum slope
Lowenstein Jensen medium

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12
Q

Blood agar

A

Autoclaved nutrient agar cooled to 50°C
5-10% sterile sheep RBC
Enriched + differential media

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13
Q

Chocolate agar

A

Autoclaved nutrient agar cooled to 70°C
5-10% sterile sheep RBCs
More nutritious - Release factors V and X

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14
Q

Loeffler’s serum slope used to grow

A

Corynebacterium diphtheria (Klebs Loeffler bacilli)
6-8 hours to grow

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15
Q

Composition of Lowenstein Jensen media

A

Tuberculosis
Coagulated hen’s egg
Mineral salt solution
Asparagine
Malachite green

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16
Q

All culture media are sterilized by

A

Autoclave except Loeffler’s serum slope and Lowenstein Jensen media

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17
Q

Enrichment broth

A

Liquid media that is selective in nature

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18
Q

Examples of Enrichment Broth

A

Alkaline peptone water
Selenite F broth
Tetrathionate broth

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19
Q

Which organism used to grow on Alkaline Peptone water

A

Vibrio

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20
Q

Organisms grown on Selenite F broth and Tetrathionate broth

A

Salmonella and Shigella

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21
Q

Selective media

A

Addition of components to inhibit selected bacteria

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22
Q

Composition of MacConkey agar

A

PLANT
Peptone
Lactose - Differential media
2% Agar
Neutral red - Indicator media
Taurocholate - Selective media

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23
Q

Composition of Mannitol salt agar

A

Selective media - Salt (allows S. Aureus to grow)
Differential media - Mannitol fermenter +/- : Yellow
Indicator media - Phenol red

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24
Q

CLED Composition

A

Cysteine lactose Electrolyte deficient
Differential media - LF +/-
Selective media - Lactose
Indicator - Bromothymol blue

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25
Q

Which one is better CLED or McConkey agar

A

CLED > MacConkey
Because CLED allows both gram+ve and -ve to grow

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26
Q

TCBS Composition

A

Thiosulfate citrate Bile salt sucrose
Selective medium - Bile salt
Differential media - Sucrose fermenter +/-
Indicator - Bromothymol blue

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27
Q

On TCBS , color shown by sucrose fermenters and Non Sucrose fermenters

A

Sucrose fermenter - Yellow color (V. Cholera)
Non Sucrose fermenter - Green color (V. Parahemolyticus)

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28
Q

CVBA used a selective media for which organism

A

S. Pyogenes

29
Q

Modified Thayer Martin is used as selective media for which organism

A

N. Meningitidis
N. Gonorrhea

30
Q

Cetrimide agar is used as selective media for which organism

A

Pseudomonas

31
Q

DCA And XLD used as selective media for which organism

A

Deoxycholate citrate agar
Xylose lysine deoxycholate
Used for Salmonella and Shigella

32
Q

Potassium tellurite agar is used as selective media for which organism

A

Corynebacterium diphtheria - Black color

33
Q

PLET is used as Selective media for which organism

A

Polymxin lysozyme EDTA thallous acetate
Used for B. Anthracis

34
Q

MYPA and PEMBA used as Selective media for which organism

A

Bacillus cereus

35
Q

Differential media used for lactose fermenters

A

MacConkey
CLED

36
Q

Differential media used to differentiate Alpha, beta and gamma Hemolysis

A

Blood agar

37
Q

Differential media used to differentiate Sucrose fermenter

A

TCBS (Thiosulfate citrate bile salt sucrose)

38
Q

Differential media used to differentiate Mannitol fermenters

A

Mannitol Salt agar (MSA)

39
Q

Transport media are used to maintain

A

Vitality of bacteria

40
Q

Amies And Stuart media used as Transport media for which organism

A

Neisseria

41
Q

Pike’s Media used as Transport media for which organism

A

S pyogenes

42
Q

Carry Blair medium is used as Transport media for which organism

A

Vibrio cholera

43
Q

SBGS used as Transport media for which organism

A

Sachs buffered Glycerol saline
For Salmonella and Shigella

44
Q

Media to grow Anaerobic bacteria

A

Robertson Cooked meat broth

45
Q

In case of Proteolytic reaction on RCMB, meat color turns into

A

Black - C tetani

46
Q

In case of Saccharolytic reaction on RMSB, meat color turns into

A

Pink - C. Perfringes

47
Q

Where to keep slide to maintain Anaerobiasis

A

Keep slide in Mc Intosh and Fildes anaerobic jar

48
Q

Method of choice for Anaerobiasis

A

GASPAK

49
Q

Culture Techniques

A

Streak culture
Stroke culture
Lawn culture
Gelatin stab culture

50
Q

Culture Technique to obtain pure colonies

A

Streak culture

51
Q

Uses of Stroke culture

A

Provide a pure growth for bacteria of slide agglutination and other Diagnostic methods

52
Q

Lawn culture is also known as and its uses

A

AKA - Carpet culture
Used for - Antibiotic sensitivity testing, Preparation of Bacterial antigens and vaccines
Bacteriophage typing

53
Q

Gelatin stab culture Examples

A

Inverted fir tree appearance - B. Anthracis
Fir tree appearance - C. Tetani
Napiform/turnip appearance - V. Cholera

54
Q

Difference between Pour plate and spread plate method

A

Pour plate - Add bacteria then add agar on top of it
Bacterial growth going to be noted under the surface also
Spread culture - First agar then add bacteria

55
Q

Minimal inhibitory concentration definition

A

Lowest concentration of bacteria that inhibits the growth of pathogen in medium

56
Q

Minimal bactericidal concentration (MBC) Definition

A

Minimum concentration of antibiotics that kills the bacteria in a medium

57
Q

At what MIC, Bacterial growth is inhibited

A

4microgm/ml

58
Q

Methods of antibiotics sensitivity testing

A

Dilution method
Disc Diffusion method
Stokes disc Diffusion method
Epsilometer test
Automated methods

59
Q

Dilution method procedure

A

Inoculum prepared - add E coli to sterile peptone water and incubate - After growth measure the turbidity using Sphectrophotometer/McFarland’s standard media

60
Q

0.5 MacFarlands is equal to

A

1.5 x 10^8 CFU/ml

61
Q

Types of Dilution broth

A

Mircobroth - 96 wells plate, Saves medium and time used
Macrobroth - Done in test tubes, requires time

62
Q

Disc Diffusion method is also known as

A

Kirby Bauer Disc Diffusion method

63
Q

Agar used for disc Diffusion method/Kirby Bauer Disc Diffusion method

A

CAMHA (Cation adjusted mueller Hinton agar)

64
Q

Disc Diffusion method procedure

A

Lawn culture - Incubate overnight - Disperse Antibiotic disc (25mm distance) - overnight incubate at 37°C

65
Q

Interpretation of Disc Diffusion method and Disadvantage

A

Observe zone of inhibition around each disc
If zone of inhibition present - Sensitivity +ve
If absent - Resistant
Measure diameter of Zone inhibition
Disadvantage - No quantification (MIC)

66
Q

Strokes disc Diffusion method

A

All others same as Disc Diffusion method
Added control Strain and comparison provided

67
Q

Epsilometer test

A

Provides MIC
Strip is used to differentiate concentration of antibiotics

68
Q

Example of Automated method

A

VITEK