Lec 5

Question 1

Primary goal of antimicrobial susceptibility testing

Answer 1

Determine whether the bacterial isolate is capable of expressing resistance of the therapeutic antimicrobial agents

Question 2

Universally susceptible to penicillin

Answer 2

Group A b-hemolytic Streptococcus

Question 3

The drug of choice in treating infections caused by this bacterium

Answer 3

Penicillin

Question 4

Grown directly from agar plates to match the turbidity of the 0.5 McFarland Standard

Answer 4

Pure culture

Question 5

Newly inoculated bacterial suspension and McFarland standard are compared against?

Answer 5

Dark background

Question 6

The turbidity of the bacterial suspension should be the same as that of the McFarland standard (true or false)

Answer 6

True

Question 7

Occur if too few bacteria are tested

Answer 7

False-susceptible results

Question 8

Outcome of testing too many bacteria

Answer 8

False-resistant results

Question 9

Most widely used method of inoculum standardization

Answer 9

McFarland turbidity standard

Question 10

Most commonly used McFarland turbidity standard

Answer 10

McFarland 0.5 standard which contains 99.5 mL of 1% sulfuric acid and 0.5 mL of 1.175% barium chloride

Question 11

Convenient and more precise alternative to visual adjustment to match the McFarland standard

Answer 11

Nephelometric or spectrophotometric

Question 12

Antimicrobial agents chosen for testing against a particular bacteria isolate

Answer 12

Antimicrobial battery or panel

Question 13

Publishes up-to-date tables listing potential antimicrobial agents

Answer 13

Clinical and Laboratory Standards Institute

Question 14

Uses a liquid medium

Answer 14

Broth dilution

Question 15

Total broth volume of macrodilution

Answer 15

1mL or greater

Question 16

Need multiple large test tubes, thus the test is rarely used because it is cumbersome and labor intensive

Answer 16

Macrodilution

Question 17

Total broth of microdilution

Answer 17

0.05 to 0.1 mL

Question 18

Accomplished in a single microtiter tray

Answer 18

Microdilution

Question 19

More commonly used broth dilution

Answer 19

Microdilution

Question 20

No antimicrobial agent is added

Answer 20

Growth control

Question 21

Not inoculated in bacterial suspension

Answer 21

Sterility control

Question 22

In the broth dilution, trays are incubated at?

Answer 22

35degree C for 16 to 20 hours

Question 23

Antimicrobial agent in question may be an appropriate choice for treating the infection caused by the organism

Answer 23

Susceptible

Question 24

Not inhibited with serum-achievable levels of the drug

Answer 24

Resistant

Question 25

Tube color that signify growth

Answer 25

Green

Question 26

Tube color that signify no growth

Answer 26

Pink

Question 27

Uses agar-based medium

Answer 27

Agar dilution method

Question 28

Allows examination of one or more

Answer 28

Agar dilution method

Question 29

Disadvantage of agar dilution method

Answer 29

Labor insensitive, not commonly used

Question 30

Referred as the Kirby Bauer method

Answer 30

Disk diffusion method