ANTIBIOTIC SENSITIVITY TESTING

Question 1

What are Antibiotics

Answer 1

they are chemical agents that are produced by organisms

Question 2

What is the zone of inhibition?

Answer 2

It is the effectiveness of a particular antibiotic measured by its presence

Question 3

What are the factors of disc-plate technique?

Answer 3

• the rate of diffusion of the drug through the agar
• size of inoculum
• rate of growth
• susceptibilit of the microorganism to the antibiotic

Question 4

What are the 4 antibiotic discs used for the antibiotic sensitivity testing?

Answer 4

• Tetracycline
• Polymyxin B
• Penicillin G
• Erythromycin

Question 5

What is the mode of a action for Tetracycline?

Answer 5

Prevents binding of tRNA to 70S ribosomes

Question 6

What is the purpose of Penicillin?

Answer 6

Inhibits synthesis of peptidoglycan

Question 7

What is the Erythromycin action?

Answer 7

Inhibits protein synthesis

Question 8

What is the mode of action for Polymyxin B

Answer 8

Alters membrane permeability; binds to phospholipids

Question 9

What is the Streptomycin for?

Answer 9

It affects translation by attaching onto bacterial ribosomes

Question 10

Differentiate between:
a.) antibiotics and antimicrobial drugs
b.) broad and narrow spectrum antibiotics

Answer 10

a.) targets bacteria and used for treating bacterial infections, acts on microbes
b.) targets many, targets few

Question 11

What factors influence the size of the zones of inhibition for an antibiotic?

Answer 11

the size of the filter paper and incubation temp