ANTIBIOTIC SENSITIVITY TESTING Flashcards
What are Antibiotics
they are chemical agents that are produced by organisms
What is the zone of inhibition?
It is the effectiveness of a particular antibiotic measured by its presence
What are the factors of disc-plate technique?
- the rate of diffusion of the drug through the agar
- size of inoculum
- rate of growth
- susceptibilit of the microorganism to the antibiotic
What are the 4 antibiotic discs used for the antibiotic sensitivity testing?
- Tetracycline
- Polymyxin B
- Penicillin G
- Erythromycin
What is the mode of a action for Tetracycline?
Prevents binding of tRNA to 70S ribosomes
What is the purpose of Penicillin?
Inhibits synthesis of peptidoglycan
What is the Erythromycin action?
Inhibits protein synthesis
What is the mode of action for Polymyxin B
Alters membrane permeability; binds to phospholipids
What is the Streptomycin for?
It affects translation by attaching onto bacterial ribosomes
Differentiate between:
a.) antibiotics and antimicrobial drugs
b.) broad and narrow spectrum antibiotics
a.) targets bacteria and used for treating bacterial infections, acts on microbes
b.) targets many, targets few
What factors influence the size of the zones of inhibition for an antibiotic?
the size of the filter paper and incubation temp
