[2S] Exp 8 & 9 AT & Test for AR Flashcards

1
Q

AST : KIRBY-BAUER DISK DIFFUSION

T/F: Once agent has been identified & deemed as clinically significant = proper selection of antimicrobial agents is performed

A

T

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1
Q

Provide MIC (minimum inhibitory concentration) values or zones of inhibition established using cut-off
points/break off

A

Kirby-Bauer Disk Method

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2
Q

AST : KIRBY-BAUER DISK DIFFUSION

Spreading of bacteria on an agar plate and placing paper discs impregnated with antibiotics on the plate

A

Disk Diffusion

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3
Q

AST : KIRBY-BAUER DISK DIFFUSION

Area around antibiotic disk where no bacterial growth can be seen

A

Zone of Inhibition

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4
Q

AST : KIRBY-BAUER DISK DIFFUSION

Zone indicates?

A

antibiotic is successful in stopping bacterial growth or killing bacteria

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5
Q

AST : KIRBY-BAUER DISK DIFFUSION

Diameter is measured to?

A

compare efficacy of antibiotics and monitor antimicrobial resistance

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6
Q

AST : KIRBY-BAUER DISK DIFFUSION

Specimen used

A

< 24 hour-old test culture on BAP, TSA or NAP

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7
Q

AST : KIRBY-BAUER DISK DIFFUSION

Turbidity of suspension is visually compared to

A

0.5 McFarland standard

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8
Q

AST : KIRBY-BAUER DISK DIFFUSION

Turbidity of inoculum is adjusted by

A

Adding sufficient sterile saline or adding more colonies

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9
Q

AST : KIRBY-BAUER DISK DIFFUSION

Desired turbidity of the inoculum

A

same turbidity with McFarland Standard

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10
Q

AST : KIRBY-BAUER DISK DIFFUSION - INOCULATION OF MHA PLATE

Material used to dip in standardized inoculum suspension

A

Sterile cotton swab

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11
Q

AST : KIRBY-BAUER DISK DIFFUSION - INOCULATION OF MHA PLATE

Excess fluid in cotton swab

A

Pressed and rotated multiple times against wall of test tube

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12
Q

AST : KIRBY-BAUER DISK DIFFUSION - INOCULATION OF MHA PLATE

Manner of streaking (surface medium)

A

Inoculated by overlap method of streaking

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13
Q

AST : KIRBY-BAUER DISK DIFFUSION - INOCULATION OF MHA PLATE

Rotate plate ___ each time for even distribution

A

60°

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14
Q

AST : KIRBY-BAUER DISK DIFFUSION - INOCULATION OF MHA PLATE

T/F: After streaking, rim-edge the medium

A

T

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15
Q

AST : KIRBY-BAUER DISK DIFFUSION - INOCULATION OF MHA PLATE

Number of times plate is rotated

A

3-4x to ensure that it’s confluent

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16
Q

AST : KIRBY-BAUER DISK DIFFUSION - INOCULATION OF MHA PLATE

Inoculation is done [time] from time of standard inoculum was prepared

A

<15 minutes

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17
Q

AST : KIRBY-BAUER DISK DIFFUSION - INOCULATION OF MHA PLATE

Place ___ then apply antibiotic disks

A

3-5 minutes

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18
Q

AST : KIRBY-BAUER DISK DIFFUSION - APPLICATION OF ANTIBIOTIC DISKS

Place disks evenly distributed
o At least ____ from each other
o At least ____ from edge of the plate

A

24mm
10mm

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19
Q

AST : KIRBY-BAUER DISK DIFFUSION - APPLICATION OF ANTIBIOTIC DISKS

Plates are inverted and placed in incubator set at ____ for _____

A

35-37C; 16-18 hours

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20
Q

Uses standardized amount of test inoculum present in Mueller Hinton Broth (MHB) and a selected antimicrobial agent

A

Broth Dilution

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21
Q

AST : BROTH MACRODILUTION OR
MACROBTROTH DILUTION

Medium used

A

Mueller Hinton Broth (MHB)

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22
Q

AST : BROTH MACRODILUTION OR
MACROBTROTH DILUTION

Antimicrobial agent is diluted ___-fold

A

two

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23
Q

AST : BROTH MACRODILUTION OR
MACROBTROTH DILUTION

Lowest concentration of antimicrobial agent that
completely inhibits visible growth

A

MIC

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24
Q

AST : BROTH MACRODILUTION OR
MACROBTROTH DILUTION

Interpretative categories

A

o Susceptible (S)
o Intermediate (I)
o Resistant (R)

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25
Q

AST : BROTH MACRODILUTION OR
MACROBTROTH DILUTION

2 categories

A

Broth microdilution & Broth macrodilution

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26
Q

AST : BROTH MACRODILUTION OR
MACROBTROTH DILUTION

Main difference of the 2 categories

A

volume of the MHB used

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27
Q

AST : BROTH MACRODILUTION OR
MACROBTROTH DILUTION

Specimen used

A

Culture on BAP

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27
Q

AST : BROTH MACRODILUTION

Final Bacterial Concentration

A

5x10^5 CFU/mL

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28
Q

AST : BROTH MACRODILUTION

Adjusted inoculum is diluted _____ by adding 0.1mL of standardized inoculum in 19.9 mL MHB

A

1:200

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29
Q

AST : BROTH MACRODILUTION

Test tube 1-10 is for

A

actual test

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29
Q

AST : BROTH MACRODILUTION

How many test tubes are needed?

A

13 sterile test tubes

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30
Q

AST : BROTH MACRODILUTION

Test tube 12 is for

A

Broth Control (BC)

30
Q

AST : BROTH MACRODILUTION

Test tube 11 is for

A

Inoculum Control (IC)

31
Q

AST : BROTH MACRODILUTION

Test tube 13 is for

A

Antibiotic Control (AC)

32
Q

AST : BROTH MACRODILUTION

Incubate ____ ambient air for ____

A

35-37°C; 18-24 hrs

33
Q

AST : BROTH MACRODILUTION

Growth on control tube 11

A

Visible growth

34
Q

AST : BROTH MACRODILUTION

Growth on control tube 12 & 13

A

No visible growth

35
Q

AST : BROTH MACRODILUTION

determine tube with lowest antibiotic concentration with no visible growth

A

MIC

36
Q

DETERMINATION OF MBC

T/F: Pipette 1 mL from each tube showing no visible growth and subculture to agar plates

A

F; 0.01 mL

37
Q

DETERMINATION OF MBC

T/F: After pipetting 0.01 mL from each tube showing no visible growth to agar plates, incubate 18-24 hrs at 35-37°C ambient air

A

T

38
Q

AST : BROTH MACRODILUTION

lowest antibiotic concentration that results in 99% killing

A

MBC

39
Q

AST : BROTH MACRODILUTION

Determined by identifying the plate with lowest
antibiotic concentration showing no visible growth

A

MBC

40
Q

Due to different external and internal factors that prevent the action of antimicrobials

A

Antibiotic Resistance

41
Q

TEST FOR ANTIMICROBIAL RESISTANCE

Cleaves beta lactam ring of
penicillin and cephalosporins

A

Beta lactamase enzyme

42
Q

TEST FOR ANTIMICROBIAL RESISTANCE

Detected in Gr (+) & Gr (-) Bacterias

A

Beta Lactamase

43
Q

TEST FOR ANTIMICROBIAL RESISTANCE

A
44
Q

TEST FOR BETA LACTAMASE

Bacterias detected

A

o Staphylococcus
o H. Influenzae
o N. gonorrhoeae

45
Q

TEST FOR BETA LACTAMASE

3 Methods used

A

Iodometric
Acidimetric
Chromogenic

45
Q

TEST FOR BETA LACTAMASE

A
46
Q

TEST FOR BETA LACTAMASE

Most sensitive method

A

Chromogenic

47
Q

TEST FOR BETA LACTAMASE

Positive result

A

Color change from yellow to red

48
Q

TEST FOR BETA LACTAMASE

Bacteria that take up to 1 hr to develop a color change

A

Staphylococcus

49
Q

TEST FOR BETA LACTAMASE

Specimen

A

Culture of Staphylococcus growing in BAP or TSA

50
Q

TEST FOR ANTIMICROBIAL RESISTANCE

For determining MRSA

A

Cefoxitin Screen Test

51
Q

CEFOXITIN SCREEN TEST PROCEDURE

Streak standardized inoculum using _________

A

Disk Diffusion Method

51
Q

TEST FOR ANTIMICROBIAL RESISTANCE

Excellent induced or mecA gene

A

Cefoxitin

52
Q

TEST FOR ANTIMICROBIAL RESISTANCE

Code for PBP2a responsible for methicillin and oxacillin resistance

A

mecA gene

53
Q

CEFOXITIN SCREEN TEST

Specimen

A

Culture of Staphylococcus aureus in BAP or TSA

54
Q

CEFOXITIN SCREEN TEST PROCEDURE

Place a __ ug cefoxitin disk at the center

A

30

55
Q

CEFOXITIN SCREEN TEST PROCEDURE

Measure zone inhibition of S. aureus ≥ 22 mm

A

Susceptible

55
Q

CEFOXITIN SCREEN TEST PROCEDURE

Incubate plate at ___. Do not incubate above __

A

30-35°C

56
Q

CEFOXITIN SCREEN TEST PROCEDURE

Measure zone inhibition of S. aureus ≤ 21 mm

A

Resistant

57
Q

AST

uses plastic strip

A

E-test

58
Q

AST

uses paper strip

A

Liofilchem

59
Q

AST

Quantitative assay for determining MIC

A

E-test

60
Q

AST

E-test test strip is applied onto?

A

an inoculated agar surface

60
Q

AST : GRADIENT DIFFUSION – E-TEST

T/F: After 18 hours incubation or longer, a symmetrical inhibition ellipse centered along the strip is formed

A

T

61
Q

AST

Preformed exponential gradient of antimicrobial
agent is transferred into the agar matrix

A

Test Strip

62
Q

AST : GRADIENT DIFFUSION – E-TEST

E-test specimen

A

Culture on BAP

63
Q

AST : GRADIENT DIFFUSION – E-TEST

Medium used

A

Mueller-Hinton Broth

64
Q

AST : GRADIENT DIFFUSION – E-TEST

Streak the standardized inoculum using the [technique]?

A

Overlapping Streaking Technique

65
Q

AST : GRADIENT DIFFUSION – E-TEST

Apply the strip to the agar surface with the scale facing
_______ and code of the strip to the outside of the plate

A

upwards

66
Q

AST : GRADIENT DIFFUSION – E-TEST

Set up time

A

<5 minutes

67
Q

AST : GRADIENT DIFFUSION – E-TEST

T/F: The antibiotic gradient should be in complete contact with the agar surface

A

T

68
Q

AST : GRADIENT DIFFUSION – E-TEST

Time to Result

A

16-20 hrs

68
Q

AST : GRADIENT DIFFUSION – E-TEST

T/F: Strip can be repositioned within 5 minutes from its application

A

F; 3 mins

69
Q

AST : GRADIENT DIFFUSION – E-TEST

Consult the?

A

MIC Test Strip Photographic Guide

69
Q

AST : GRADIENT DIFFUSION – E-TEST

Indicates that the value is greater than or equal to
(≥) the highest value on the scale

A

Growth along the entire gradient i.e. no inhibition ellipse

70
Q

AST : GRADIENT DIFFUSION – E-TEST

An inhibition ellipse that intersects below the lower end of the scale is read as _______ the lowest value

A

less than (<)

71
Q

AST : GRADIENT DIFFUSION – E-TEST

T/F: Observe where the relevant inhibition ellipse intersects the strip and read the MIC at complete inhibition

A

T