FINALS: L1 - Antimicrobial Sensitivity Testing

Question 1

Procedure used to produce antimicrobial susceptibility profiles and detect resistance to agents that maybe used therapeutically.

Answer 1

Antimicrobial susceptibility testing methods

Question 2

T OR F
Increased concentration of calcium & magnesium ions
leads to increased activity of aminoglycosides against Pseudomonas aeruginosa and decreased activity of the tetracyclines against all bacteria

Answer 2

False

• decreased activity

Question 3

T OR F
Increased levels of thymidine or thymine leads to decreased activity of the sulfonamides, trimethoprim and trimethoprim sulfamethoxazole

Answer 3

True

Question 4

T OR F

Increased pH levels leads to FALSE RESISTANT

Answer 4

False

Question 5

T OR F

Plates poured thicker than 4mm leads to FALSE RESISTANT

Answer 5

True

Question 6

T OR F

The most important variable in controlling reproducibility of the test is the density of the inoculum

Answer 6

True

Question 7

T OR F
Only pure cultures can be tested and it is essential that the inoculum is adjusted to the concentration of a 0.5 McFarland Standard (which is equal to 1:10 dilution)

Answer 7

False

0.5 McFarland Standard which is equal to a 1:100 dilution

Question 8

T OR F
The most commonly used is the McFarland 0.5 standard which contains 99.5 mL of 1% sulfuric acid and 0.5 mL of 1.175% barium chloride.

Answer 8

True

Question 9

How are you going to measure two antibiotic disks’ inhibitions which are overlapping each other

Answer 9

Measure the radius and Multiply by 2

Question 10

T OR F
Increased moisture can cause too much growth which can cause false resistant results and decrease moisture can cause small growth which results into a poor susceptible result.

Answer 10

True